- 1. Small strain deformation measurements of konjac glucomannan solutions and the influence of borate cross-linking.
The dynamic rheology of aqueous solutions of konjac glucomannan has been evaluated over a range of concentrations up to 2.35%, and the effect of borate cross-linking of such solutions evaluated in the range 0.02-40mM borate. In preliminary work, conventional parallel plate geometries were employed and in situ cross-linking was investigated. For borate cross-linked samples a superior method, however, was found to be measurement of pre-formed cores of cross-linked polymer into which a four-bladed vane geometry was introduced. In order to compare with other associating polymer systems, rheological data were analysed by defining plateau moduli, corresponding relaxation times and zero shear viscosities and the scaling behaviour of these parameters with polymer and cross-linker concentrations was established. Maxwell fits and time-concentration superposition procedures were investigated. The rheological properties of the cross-linked polymer were shown to be the result of both increased network connectivity and retarded network dynamics.
Copyright © 2013 Elsevier Ltd. All rights reserved....(more)
Ratcliffe I, et al. Carbohydr Polym 2013 Jun 5;95(1):272-81.
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- 2. Sulfation and biological activities of konjac glucomannan.
The sulfation of konjac glucomannan and its anti-HIV and blood anticoagulant activities were investigated. Konjac glucomannan is a polysaccharide occurring naturally in konjac plant tubers and has high molecular weights. Solubility in water is very low, and the aqueous solutions at low concentrations have high viscosity. Before sulfation, hydrolysis by diluted sulfuric acid was carried out to decrease the molecular weights of M¯n=19.2×10(4)-0.2×10(4). Sulfation with piperidine-N-sulfonic acid or SO3-pyridine complex gave sulfated konjac glucomannans with molecular weights of M¯n=1.0×10(4)-0.4×10(4) and degrees of sulfation (DS) of 1.3-1.4. It was found that the sulfated konjac glucomannans had potent anti-HIV activity at a 50% effective concentration, (EC50) of 1.2-1.3μg/ml, which was almost as high as that of an AIDS drug, ddC, whose EC50=3.2μg/ml, and moderate blood anticoagulant activity, AA=0.8-22.7units/mg, compared to those of standard sulfated polysaccharides, curdlan (10units/mg) and dextran (22.7units/mg) sulfates. Structural analysis of sulfated konjac glucomannans with negatively charged sulfated groups was performed by high resolution NMR, and the interaction between poly-l-lysine with positively charged amino groups as a model compound of proteins and peptides was measured by surface plasmon resonance measurement, suggesting that the sulfated konjac glucomannans had a high binding stability on immobilized poly-l-lysine. The binding of sulfated konjac glucomannan was concentration-dependent, and the biological activity of the sulfated konjac glucomannans may be due to electrostatic interaction between the sulfate and amino groups.
Copyright © 2013. Published by Elsevier Ltd....(more)
Bo S, et al. Carbohydr Polym 2013 May 15;94(2):899-903.
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- 3. Hydrolysis of konjac glucomannan by Trichoderma reesei mannanase and endoglucanases Cel7B and Cel5A for the production of glucomannooligosaccharides.
In this paper we describe the enzymatic hydrolysis of konjac glucomannan for the production of glucomannooligosaccharides using purified Trichoderma reesei mannanase, endoglucanases EGI (Tr Cel7b) and EGII (Tr Cel5a). Hydrolysis with each of the three enzymes produced a different pattern of oligosaccharides. Mannanase was the most selective of the three enzymes in the hydrolysis of konjac mannan and over 99% of the formed oligosaccharides had mannose as their reducing end pyranosyl unit. Tr Cel5A hydrolysate shared similarities with mannanase and Tr Cel7B hydrolysates and the enzyme had the lowest substrate specificity of the studied enzymes. The hydrolysate of Tr Cel7B contained a series of oligosaccharides with non-reducing end mannose (M) and reducing end glucose (G) (MG, MMG, MMMG, and MMMMG). These oligosaccharides were isolated from the hydrolysate by size exclusion chromatography in relatively high purity (86-95%) and total yield (23% of substrate). The isolated oligosaccharides were characterized using acid hydrolysis and HPAEC-PAD (carbohydrate composition), HPLC-RI and HPAEC-MS (to determine the DP of purified oligosaccharides), enzymatic hydrolysis (determination of non-reducing end carbohydrate) and NMR (both 1D and 2D, to verify structure and purity of purified compounds). Hydrolysis of konjac mannan with a specific enzyme, such as T. reesei Cel7B or mannanase, followed by fractionation with SEC offers the possibility to produce glucomannooligosaccharides with defined structure. The isolated oligosaccharides can be utilised as analytical standards, for determination of bioactivity of oligosaccharides with defined structure or as substrates for defining substrate specificity of novel carbohydrate hydrolyzing enzymes.
Copyright © 2013 Elsevier Ltd. All rights reserved....(more)
Mikkelson A, et al. Carbohydr Res 2013 May 3;372:60-8.
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- 4. Synergetic degradation of konjac glucomannan by γ-ray irradiation and hydrogen peroxide.
Konjac glucomannan (KGM) samples were irradiated with (60)Co γ-rays with a radiation dose of 50kGy in the presence and absence of hydrogen peroxide. The average molecular weight (Mw) and polydispersity index (PDI) of untreated and degraded samples were measured by gel permeation chromatography (GPC), revealing that γ-rays and hydrogen peroxide had a synergetic effect on degradation. Structures of untreated and degraded products were characterized with ultraviolet-visible (UV) and Fourier-transform infrared (FT-IR) spectroscopies, and X-ray diffraction (XRD). Results showed that there was no significant change in the main chain of KGM following degradation, although the crystallinity of KGM decreased. A synergetic effect of γ-rays and hydrogen peroxide was also found in the structural characterization of KGM. The physical properties of KGM changed markedly following degradation, which may increase its application potential. The mechanism of degradation of KGM in the presence and absence of hydrogen peroxide was also investigated.
Copyright © 2012 Elsevier Ltd. All rights reserved....(more)
Pan T, et al. Carbohydr Polym 2013 Apr 2;93(2):761-7.
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- 5. Optimization of hydrolysis conditions for the production of glucomanno-oligosaccharides from konjac using β-mannanase by response surface methodology.
Glucomanno-oligosaccharides (GMO), usually produced from hydrolysis of konjac tubers with a high content of glucomannan, have a positive effect on Bifidobacterium as well as a variety of other physiological activities. Response surface methodology (RSM) was employed to optimize the hydrolysis time, hydrolysis temperature, pH and enzyme to substrate ratio (E/S) to obtain a high GMO yield from konjac tubers. From the signal-factor experiments, it was concluded that the change in the direct reducing sugar (DRS) is consistent with total reducing sugar (TRS) but contrary to the degree of polymerization (DP). DRS was used as an indicator of the content of GMO in the RSM study. The optimum RSM operating conditions were: reaction time of 3.4 h, reaction temperature of 41.0°C, pH of 7.1 and E/S of 0.49. The results suggested that the enzymatic hydrolysis was enhanced by temperature, pH and incubation time. Model validation showed good agreement between experimental results and the predicted responses.
Copyright © 2012 Elsevier Ltd. All rights reserved....(more)
Chen J, et al. Carbohydr Polym 2013 Mar 1;93(1):81-8.
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- 6. An β-1,4-xylanase with exo-enzyme activity produced by Paenibacillus xylanilyticus KJ-03 and its cloning and characterization.
Paenibacillus xylanilyticus KJ-03 was isolated from soil samples obtained from a field with Amorphophallus konjac plants. A gene encoding xylanase was isolated from KJ-03 and cloned using a fosmid library. The xynA gene encodes xylanase; it consists of 1,035 bp and encodes 345 amino acids. The amino acid sequence deduced from the P. xylanilyticus KJ-03 xylanase showed 81% and 69% identities with those deduced from the P. polymyxa E681 and Paenibacillus sp. HPL-001 xylanases, respectively. The xynA gene comprises a single domain, consisting of a catalytic domain of the glycosyl hydrolase (GH) 10 family. The xynA gene was expressed in Escherichia coli BL21 (trxB), and the recombinant xylanase was purified by Niaffinity chromatography. The purified xylanase showed optimum activity with birchwood xylan as a substrate at 40°C and pH 7.4. Treatment with Mg(2+) and Li(+) showed a slight decrease in XynA activity; however, treatment with 5 mM Cu(2+) completely inhibited its activity. The results of the thin layer chromatography analysis indicated that the major hydrolysis product was xylobiose and small amounts of xylose and xylotriose. XynA showed increased activity with oat spelt xylan and birchwood xylan, but showed only slight activity with locust bean gum....(more)
Park DJ, et al. J Microbiol Biotechnol 2013 Mar;23(3):397-404.
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- 7. Syntheses and characterization of konjac glucomannan acetate and their thermal and mechanical properties.
Fully substituted glucomannan triacetate (GMTAc) (degree of substitution (DS)=3.0) was prepared from konjac glucomannan (KGM) treated with acetic acid and trifluoroacetic anhydride (TFAA). The peaks in the (1)H- and (13)C NMR spectra of GMTAc were assigned in detail based on two-dimensional (DQF-COSY, HSQC and HMBC) NMR analysis. Glucomannan acetate samples (GMAc) with different degrees of substitution (DS=1.3, 1.7, 2.0 and 2.8) were prepared by partial deprotection of GMTAc. Thermal properties of GMAcs including GMTAc were analyzed by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Their decomposition temperatures were higher than that of KGM, and increased with increase in DS. DSC measurements revealed that GMAc had a high glass transition temperature in the range of 178-219 °C, which decreased with increase in DS. The samples did not exhibit melting peaks, indicating that the GMAcs were amorphous. All GMAcs formed transparent films upon solvent casting, and tensile tests revealed that GMAc had a higher tensile strength and elongation to break at lower DS (1.3 and 1.7) compared to higher DS (2.0, 2.8 and 3.0). This means that the mechanical properties of GMAc could be controlled by DS.
Copyright © 2012 Elsevier Ltd. All rights reserved....(more)
Enomoto-Rogers Y, et al. Carbohydr Polym 2013 Feb 15;92(2):1827-34.
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- 8. Antibacterial activity of konjac glucomannan/chitosan blend films and their irradiation-modified counterparts.
Antibacterial activity of glucomannan/chitosan (KGM/CHI) blend films and their irradiation-modified counterparts were tested. The KGM/CHI blend films after irradiation showed good antibacterial effects against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. Antibacterial activity of the blend films increased with the increase of the content of chitosan. After different dose irradiation, there was no obvious change in the antibacterial effects against St. aureus of the blend films, but the antibacterial effects against E. coli and P. aeruginosa increased significantly.
Copyright © 2012 Elsevier Ltd. All rights reserved....(more)
Du X, et al. Carbohydr Polym 2013 Feb 15;92(2):1302-7.
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- 9. Study on preparation and separation of Konjac oligosaccharides.
To study the preparation and separation of Konjac oligosaccharides, Konjac Glucomannan was degraded by the combination of γ-irradiation and β-mannanase, and then the degradation product was separated by ultrafiltration. To our interest, for most of Konjac oligosaccharides obtained by this method, the molecular mass was lower than 2200 Da. In addition, the 1000 Da molecular weight cut off membrane could effectively separate the Konjac oligosaccharides. In conclusion, the combination of γ-irradiation and β-mannanase was an efficient method to obtain Konjac oligosaccharides, and the oligosaccharides of molecular mass lower than 1000 Da could be effectively separated by ultrafiltration.
Copyright © 2012 Elsevier Ltd. All rights reserved....(more)
Jian W, et al. Carbohydr Polym 2013 Feb 15;92(2):1218-24.
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- 10. The Chinese Pueraria root extract (Pueraria lobata) ameliorates impaired glucose and lipid metabolism in obese mice.
The incidence of type 2 diabetes and metabolic disease is rapidly increasing, but effective therapies for their prevention and treatment have been poorly tolerated or minimally effective. In this study, chronic administration of kudzu root extract (8 months, 0.2%, w/w, in diet) decreased baseline fasting plasma glucose (183±14 vs. 148±11 mg/dl) and improved glucose and insulin tolerance in C57BL/6J ob/ob mice (1.67±0.17 ng/ml [kudzu treated] vs. 2.35±0.63 ng/ml [control]), but such treatment did not alter these parameters in lean control mice. Among the mice on the kudzu supplementation, plasma levels of isoflavone metabolites were significantly higher in ob/ob versus lean control mice, and unmetabolized puerarin (11.50±5.63 ng/g) was found in adipose tissue only in the treated mice. Together, these data demonstrate that a puerarin containing kudzu diet improves glucose and insulin responsiveness in ob/ob mice, suggesting that puerarin may be a beneficial adjuvant for treating metabolic disease....(more)
Prasain JK, et al. Phytomedicine 2012 Dec 15;20(1):17-23.
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- 11. Kudzu root extract does not perturb the sleep/wake cycle of moderate drinkers.
OBJECTIVES:
According to ancient Chinese medicine, kudzu root has been used as an ingredient to treat alcohol intoxication for centuries. Kudzu root extract is effective at reducing alcohol intake in animals and in humans, both in a natural-settings laboratory environment and on an outpatient basis. In dependent populations, withdrawal from alcohol is associated with disturbed sleep. These disturbances to the quantity and quality of sleep likely impact relapse to drinking. Many medications used to treat alcohol dependence also affect sleep. Therefore, as a possible treatment for alcohol dependence, the impact of kudzu root extract on the sleep/wake cycle is an important aspect of its effectiveness.
DESIGN:
This double-blind, placebo-controlled, crossover trial tested the effects of kudzu root extract on the sleep/wake cycles of moderate drinkers.
RESULTS:
Kudzu extract had no effect on any of the sleep parameters measured, including sleep efficiency, sleep latency, total time asleep per night, number of waking episodes, time awake per episode, number of moving minutes, number of sleep episodes, time asleep per episode, and number of immobile minutes.
CONCLUSIONS:
These data suggest that the administration of kudzu root extract does not disturb sleep/wake cycles of moderate drinkers, and as such its utility as an adjunct treatment for alcohol dependence remains free of any potential side-effects on sleep....(more)
Bracken BK, et al. J Altern Complement Med 2011 Oct;17(10):961-6.
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- 12. Identification of a naturally-occurring 8-[alpha-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl]daidzein from cultivated kudzu root.
INTRODUCTION:
Kudzu root (Radix puerariae) is a rich source of isoflavones that are effective in preventing osteoporosis, heart disease and symptoms associated with menopause. The major isoflavonoids in kudzu root extracts were reported as puerarin, daidzin and daidzein. Recently, an unknown isoflavonoid (compound 1) was detected from one-year-old kudzu root cultivated in Vietnam.
OBJECTIVE:
To identify a novel compound 1 in kudzu root extract and determine the structure of the compound by ESI(+) TOF MS-MS, (1)H-, (13)C-NMR and enzymatic hydrolysis.
METHODOLOGY:
Samples were prepared by extraction of one-year-old kudzu root with 50% ethanol and the isoflavonoids were purified using recycling preparative HPLC. Unknown compound 1 was detected using UV-light at 254 nm in TLC and HPLC analyses. The molecular weight of 1 was determined using a TOF mass spectrometer equipped with an electrospray ion source. The structure of 1 was determined from the (13)C and (1)H NMR spectra recorded at 100.40 and 400.0 MHz, respectively.
RESULTS:
ESI(+) TOF MS-MS analysis shows that 1 is a puerarin diglycoside. The interglycosidic linkage of diglycoside determined by (1)H-, (13)C-NMR, and enzymatic hydrolysis suggests that 1 has a glucosyl residue linked to puerarin by an alpha-1,6-glycosidic bond. This compound is the first naturally-occurring 8-[alpha-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl]daidzein in kudzu root. The concentration of glucosyl-alpha-1,6-puerarin in kudzu root was 2.3 mg/g as determined by HPLC.
CONCLUSION:
The results indicate that puerarin diglycoside is one of the major isoflavonoids in kudzu root and has a significant impact on the preparation of highly water-soluble glycosylated puerarin....(more)
Nguyen VD, et al. Phytochem Anal 2009 Nov-Dec;20(6):450-5.
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- 13. Chronic dietary kudzu isoflavones improve components of metabolic syndrome in stroke-prone spontaneously hypertensive rats.
The present study tested the long-term effects of dietary kudzu root extract supplementation on the regulation of arterial pressure, plasma glucose, and circulating cholesterol in stroke-prone spontaneously hypertensive rats (SP-SHR). Female SP-SHR were maintained for 2 months on a polyphenol-free diet, with or without the addition of 0.2% kudzu root extract. Half of the rats in each diet group were ovariectomized, whereas the other half remained intact. Following 2 months on the diets, the 0.2% kudzu root extract supplementation (compared to control diet) significantly lowered arterial pressure (11-15 mmHg), plasma cholesterol, fasting blood glucose (20-30%), and fasting plasma insulin in both the ovariectomized and intact SP-SHR. These results indicate that long-term dietary kudzu root extract supplementation can improve glucose, lipid, and blood pressure control in intact and ovariectomized SP-SHR....(more)
Peng N, et al. J Agric Food Chem 2009 Aug 26;57(16):7268-73.
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- 14. The effect of supplementation of clove and agrimony or clove and lemon balm on growth performance, antioxidant status and selected indices of lipid profile of broiler chickens.
The study investigated the effects of diet supplementation with 1% clove flower buds powder combined with either 0.2% lemon balm extract or 0.2% agrimony extract (each of the two pulverized extracts supplied through drinking water) on body weight of broilers, total feed intake, feed conversion ratio and the carcass yield, activity of superoxide dismutase (SOD, EC 1.15.1.1) and glutathione peroxidase (GSH-Px, EC 1.11.1.9) in blood, concentration of sulfhydryl (-SH) groups, malondialdehyde (MDA), vitamin A and E, low-density lipoproteins in the blood plasma, serum cholesterol, total lipids, triglycerides and high-density lipoproteins in broiler chickens at 42 days of age. On the day of hatching, 120 male and female broilers of Cobb 500 were randomly divided into three groups. The control group (1st group) of broilers received a basal diet (BD) without any feed and water additive. Both experimental groups of chicks were fed BD enriched with clove (Syzygium aromaticum L.) powder at a dose of 10 g/kg DM for 42 days. Moreover, either lemon balm (Mellisa officinalis L.) extract or agrimony (Agrimonia eupatoria L.) extract diluted with drinking water (2:1000) was given to broilers in the 2nd and 3rd group respectively. The results indicated that feeding the diets enriched with selected herbal supplements failed to affect the growth performance of broiler chickens at 42 days of age. In addition, this supplementation had no influence on the activities of SOD and GSH-Px, concentration of vitamin A and selected lipid metabolism indices. On the other hand, we observed beneficial effects on some indices of the antioxidant status (increased concentration of -SH groups and vitamin E, decreased concentration of MDA) in the blood of broilers in both experimental groups in comparison with the control group of chickens (p < 0.05). Furthermore, a slightly better antioxidant capacity was found in the blood of broilers supplied the combination of clove and lemon balm compared to clove and agrimony (vitamin E, 11.26 ± 0.73 vs. 9.73 ± 0.64 μmol/L, p < 0.05 respectively). It could be concluded that supplementation of the diet with clove flower buds powder combined with lemon balm extract or agrimony extract dissolved in drinking water has a potential to increase the antioxidant status but fails to influence either the growth performance or the selected lipid metabolism indices of broilers at the age of 42 days....(more)
Petrovic V, et al. J Anim Physiol Anim Nutr (Berl) 2012 Dec;96(6):970-7.
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- 15. Anxiolytic and antidepressant-like effects of Melissa officinalis (lemon balm) extract in rats: Influence of administration and gender.
OBJECTIVE:
To analyse the behavioral effects of Melissa officinalis extract in rats following acute or subacute treatment.
MATERIALS AND METHODS:
The behavioral effects of an acute or subacute (10-day course) orally administered M. officinalis (MO; 0, 30, 100 or 300 mg/kg) ethanol extract were evaluated in male and female Wistar rats in elevated plus-maze (EPM), forced swimming (FS) and open field (OF) tests. The effects of diazepam (DZP; 1 mg/kg) and fluoxetine (FXT; 10 mg/kg) were also assessed.
RESULTS:
In the EPM test, the percentage of open arm entries and open arm times of both males and females given the subacute M. officinalis ethanol extract were significantly higher than those of the vehicle-treated animals but were at levels similar to those observed in the DZP group, regardless of the treatment length. In the FS test, immobility duration was significantly lower in both males and females treated with the plant extract when compared to vehicle-treated counterparts. A 10-day treatment with FXT induced the same antidepressant response, regardless of gender, and was more effective than the M. officinalis extract. Male and female rats demonstrated distinct gender profiles, and treatment × gender interactions were observed. Locomotion in the EPM and OF tests was not significantly altered by treatments.
CONCLUSION:
The potential psychoactive properties of M. officinalis may provide a unique pharmacological alternative for certain psychiatric disorders; however, the efficacy appears to be dependent on both gender and administration length....(more)
Taiwo AE, et al. Indian J Pharmacol 2012 Mar;44(2):189-92.
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- 16. Effects of Melissa officinalis L. (lemon balm) extract on neurogenesis associated with serum corticosterone and GABA in the mouse dentate gyrus.
Lemon balm, leaves of Melissa officinalis L., has been used for anti-anxiety and spasmolytics. We observed the extract of Melissa officinalis L. (MOE) on cell proliferation and neuroblast differentiation in the hippocampal dentate gyrus (DG) of middle-aged mice (12 months of age) using Ki67 and doublecortin (DCX), respectively. We also observed changes in corticosterone, GAD67 and GABA-transaminase (GABA-T) to check their possible mechanisms related to neurogenesis. We administered 50 or 200 mg/kg MOE to the animals once a day for 3 weeks. For labeling of newly generated cells, we also administered 5-bromodeoxyuridine (BrdU) twice a day for 3 days from the day of the first MOE treatment. Administration of 50 or 200 mg/kg MOE dose-dependently increased Ki67 positive nuclei to 244.1 and 763.9% of the vehicle-treated group, respectively. In addition, 50 or 200 mg/kg MOE significantly increased DCX positive neuroblasts with well-developed (tertiary) dendrites. Furthermore, MOE administration significantly increased BrdU/calbindin D-28 k double labeled cells (integrated neurons into granule cells in the DG) to 245.2% of the vehicle-treated group. On the other hand, administration of MOE reduced corticosterone levels in serum and decreased GABA-T levels in the DG homogenates. These results suggest that MOE increases cell proliferation, neuroblast differentiation and integration into granule cells by decreasing serum corticosterone levels as well as by increasing GABA levels in the mouse DG....(more)
Yoo DY, et al. Neurochem Res 2011 Feb;36(2):250-7.
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- 17. [Advances on the effects of the compounds of a phytotherapic agent (COLIMIL) on upper gastrointestinal transit in mice].
AIM:
Phytotherapic agents, such as herbal formulations containing Matricariae recutita flowers (chamomile) extract, Foeniculum vulgare fruit (fennel) extract and Melissa officinalis aerial parts (lemon balm) extract have beneficial effects on gastrointestinal tract in colicky infants. However, the mechanism is largely unexplored and, particularly, it is not clear if it affects intestinal motility. The aim of this experimental study was to evaluate the effect of different herbal formulations containing Matricariae recutita extract, Foeniculum vulgare extract and Melissa officinalis extract on upper gastrointestinal transit in mice in vivo.
METHODS:
Gastrointestinal transit was measured in male ICR mice and in croton oil-treated mice after the oral administration of herbal formulations containing chamomile, fennel and lemon balm (ColiMil) and chamomile and lemon balm (ColiMil experimental).
RESULTS:
The herbal formulations tested (0.4-0.8 mL/mouse) dose-dependently and significantly inhibited gastrointestinal transit both in control and in croton oil-treated mice. Chamomile extract and lemon balm extract reduced significantly intestinal motility, but not fennel. At similar concentration ColiMil evoked a more consistent response than ColiMil experimental.
CONCLUSION:
Our findings directly demonstrate in vivo the effect of a combination of herbal formulations on intestinal motility. The observed inhibitory effect might be studied with clinical studies to test the efficacy of these compounds in the treatment of colicky infants....(more)
Savino F, et al. Minerva Pediatr 2008 Jun;60(3):285-90. Italian.
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- 18. Testing the use of ITS rDNA and protein-coding genes in the generic and species delimitation of the lichen genus Usnea (Parmeliaceae, Ascomycota).
In lichen-forming fungi, traditional taxonomical concepts are frequently in conflict with molecular data, and identifying appropriate taxonomic characters to describe phylogenetic clades remains challenging in many groups. The selection of suitable markers for the reconstruction of solid phylogenetic hypotheses is therefore fundamental. The lichen genus Usnea is highly diverse, with more than 350 estimated species, distributed in polar, temperate and tropical regions. The phylogeny and classification of Usnea have been a matter of debate, given the lack of phenotypic characters to describe phylogenetic clades and the low degree of resolution of phylogenetic trees. In this study, we investigated the phylogenetic relationships of 52 Usnea species from across the genus, based on ITS rDNA, nuLSU, and two protein-coding genes RPB1 and MCM7. ITS comprised several highly variable regions, containing substantial genetic signal, but also susceptible to causing bias in the generation of the alignment. We compared several methods of alignment of ITS and found that a simultaneous optimization of alignment and phylogeny (using BAli-phy) improved significantly both the topology and the resolution of the phylogenetic tree. However the resolution was even better when using protein-coding genes, especially RPB1 although it is less variable. The phylogeny based on the concatenated dataset revealed that the genus Usnea is subdivided into four highly-supported clades, corresponding to the traditionally circumscribed subgenera Eumitria, Dolichousnea, Neuropogon and Usnea. However, characters that have been used to describe these clades are often homoplasious within the phylogeny and their parallel evolution is suggested. On the other hand, most of the species were reconstructed as monophyletic, indicating that combinations of phenotypic characters are suitable discriminators for delimitating species, but are inadequate to describe generic subdivisions.
Copyright © 2013 Elsevier Inc. All rights reserved....(more)
Truong C, et al. Mol Phylogenet Evol 2013 Apr 16.
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- 19. Genotoxic and antigenotoxic potentials of two Usnea species.
For ages, lichens have long been investigated popularly for biological roles, mainly antitumor, antimicrobial and antioxidant activities. Many positive results were obtained in these previous research. Thus, in this study, we aimed to determine whether extracts of Usnea articulata (UAE) and Usnea filipendula (UFE) possessing a protection against aflatoxin B1 (AFB1)-induced genotoxic and oxidative damage. The results of our studies showed that 5 μM concentrations of AFB1 increased the frequencies of sister chromatid exchange (SCE) and the level of malondialdehyde (MDA) and decreased the activities of superoxide dismutase (SOD), glutathione (GSH) and glutathione peroxidase (GPx). However, when 5, 10 and 20 µg/mL concentrations of UAE and UFE was added to AFB1, the frequencies of SCE and MDA level were decreased and SOD, GSH and GPx level were increased. The Ames (Salmonella typhimurium TA1535, TA1537) and WP2 (Escherichia coli) test systems carried out evinced that UAE and UFE possess any mutagenicity, but have antimutagenic effects. Consequently, the results of this experiment have clearly shown that UAE and UFE have strong antioxidative and antigenotoxic effects that are associated with its antioxidant nature. A detailed study can be performed to determine the antioxidant properties of each compound that will extend the use of lichen extracts in food and pharmacy industries....(more)
Ceker S, et al. Toxicol Ind Health 2013 Apr 15.
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- 20. Cytotoxic evaluation of phenolic compounds from lichens against melanoma cells.
Atranorin, lichexanthone, and the (+)-usnic, diffractaic, divaricatic, perlatolic, psoromic, protocetraric, and norstictic acids isolated from the lichens Parmotrema dilatatum (VAIN.) HALE, Usnea subcavata MOTYKA, Usnea sp., Ramalina sp., Cladina confusa (SANT.) FOLMM. & AHTI, Dirinaria aspera HÄSÄNEN, and Parmotrema lichexanthonicum ELIASARO & ADLER were evaluated against UACC-62 and B16-F10 melanoma cells and 3T3 normal cells. Sulforhodamine B assay revealed significant cytotoxic activity in protocetraric, divaricatic, and perlatolic acids on UACC-62 cells (50% growth inhibitory concentration (GI(50)) 0.52, 2.7, and 3.3 µg/mL, respectively). Divaricatic and perlatolic acids proved the most active on B16-F10 cells (GI(50) 4.4, 18.0 µg/mL, respectively) and the most cytotoxic to 3T3 normal cells. Diffractaic, usnic, norstictic, and psoromic acids were cytotoxic to UACC-62 cells in the 24.7 to 36.6 µg/mL range, as were protocetraric and diffractaic acids to B16-F10 cells (GI(50) 24.0, 25.4 µg/mL, respectively). Protocetraric acid was highly selective (selectivity index (SI*) 93.3) against UACC-62 cells, followed by norstictic, perlatolic, psoromic, and divaricatic acids, while norstictic and divaricatic acids were more selective against B16-F10 cells. The high SI* value obtained for protocetraric acid on UACC-62 cells makes it a potential candidate for the study of melanomas in experimental models. Chemometric analysis was performed to evaluate the general behavior of the compounds against the cell lines tested....(more)
Brandão LF, et al. Chem Pharm Bull (Tokyo) 2013;61(2):176-83.
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- 21. Biological Activities of Toninia candida and Usnea barbata Together with Their Norstictic Acid and Usnic Acid Constituents.
The aim of this study was to investigate the chemical composition of acetone extracts of the lichens Toninia candida and Usnea barbata and in vitro antioxidant, antimicrobial, and anticancer activities of these extracts together with some of their major metabolites. The chemical composition of T. candida and U. barbata extracts was determined using HPLC-UV analysis. The major phenolic compounds in these extracts were norstictic acid (T. candida) and usnic acid (U. barbata). Antioxidant activity was evaluated by free radical scavenging, superoxide anion radical scavenging, reducing power and determination of total phenolic compounds. Results of the study proved that norstictic acid had the largest antioxidant activity. The total content of phenols in the extracts was determined as the pyrocatechol equivalent. The antimicrobial activity was estimated by determination of the minimal inhibitory concentration using the broth microdilution method. The most active was usnic acid with minimum inhibitory concentration values ranging from 0.0008 to 0.5 mg/mL. Anticancer activity was tested against FemX (human melanoma) and LS174 (human colon carcinoma) cell lines using the microculture tetrazolium test. Usnic acid was found to have the strongest anticancer activity towards both cell lines with IC(50) values of 12.72 and 15.66 μg/mL....(more)
Rankovi? B, et al. Int J Mol Sci 2012 Nov 12;13(11):14707-22.
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- 22. Membrane-damaging potential of natural L-(-)-usnic acid in Staphylococcus aureus.
The purpose of this investigation was to try to understand the antibacterial mechanism of L-(-)-usnic acid isolated for the first time from fruticose lichen Usnea subfloridana using clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA). The minimum inhibitory concentration (MIC) of L-(-)-usnic acid against the clinical isolates of MRSA and reference strain S. aureus MTCC-96 (SA-96) was in the range 25-50 μg/ml. Treatment of both reference and clinical strains (MRSA-ST 2071) with four-fold MIC concentrations (100-200 μg/ml) of L-(-)-usnic acid reduced the viability of cells without damaging the cell wall. However, the loss of 260 nm absorbing material and increase in propidium iodide uptake was observed in both of the strains. Similarly, a combined effect of L-(-)-usnic acid (25-50 μg/ml) and 7.5 % NaCl resulted in a reduced number of viable cells within 24 h in comparison to the control. These observations clearly indicate that L-(-)-usnic acid exerts its action by disruption of the bacterial membrane. Further, in vivo efficacy showed that L-(-)-usnic acid significantly (p < 0.001) lowered the microbial load of spleen at doses ranging from 1 to 5 mg/kg. Further, toxicity studies in infected mice at doses 20 times higher than the efficacious dose indicated L-(-)usnic acid to be safe. Paradoxically, L-(-)usnic acid exhibited changes in serum triglycerides, alkaline phosphatase (ALKP) and liver organ weight in the healthy mice administered with only 25 mg/kg body weight. The results obtained in this study showed that natural L-(-)-usnic acid exerts its antibacterial activity against MRSA by disruption of the cell membrane. Further, the natural L-(-)-usnic acid was found to be safe up to 100 mg/kg body weight, thereby, making it a probable candidate for treating S. aureus infections....(more)
Gupta VK, et al. Eur J Clin Microbiol Infect Dis 2012 Dec;31(12):3375-83.
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- 23. Baseline element composition of foliose and fruticose lichens along the steep climatic gradient of SW Patagonia (Aisén Region, Chile).
Samples of foliose (Nephroma antarcticum) and fruticose (Usnea sp.) lichens were collected across a steep climatic and vegetation gradient in a remote, almost pristine region of SW Chilean Patagonia. Concentrations of major and trace elements in lichens from the rainforest were among the lowest ever reported worldwide for foliose and fruticose lichens and can be considered background levels for the region. The two lichen growth forms showed different elemental compositions mainly due to the greater capacity of foliose thalli to intercept elements from windborne and canopy-leached particles. The patterns of spatial variation in the chemical composition of lichens were effectively explained by statistical methods and reflected the different availability of wet and dry deposition along the steep climatic gradient. Baseline values established for N. antarcticum samples growing in temperate Nothofagus forests were therefore distinct from those of samples growing in more open, drier habitats. The fruticose Usnea sp. showed a higher affinity for atmophile Hg, low concentrations of lithophilic elements, and the same baseline composition whether from temperate forests or from dry, barren environments. The provided background and baseline values against which variations can be measured will be useful in the early detection of local or regional climatic and environmental change, especially in view of the planned construction of hydropower dams under the recently approved HidroAysén Project....(more)
Monaci F, et al. J Environ Monit 2012 Sep;14(9):2309-16.
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- 24. Antioxidative and cardiovascular-protective activities of metabolite usnic acid and psoromic acid produced by lichen species Usnea complanata under submerged fermentation.
CONTEXT:
Lichens have been used for various purposes such as dyes, perfumes and remedies in folk medicine indicating the pharmaceutical potential of lichens.
OBJECTIVE: r/>Lichen growth in nature is very slow. To overcome this major drawback, we standardized the culture media to culture the lichen Usnea complanata (Müll.Arg.) Motyka (Parmeliaceae) for (1) in vitro synthesis of natural lichen substances, and (2) determination of antioxidative and cardiovascular-protective activity of usnic acid and psoromic acid.
MATERIALS AND METHODS:
Lichen U. complanata has been cultured in fermentor under submerged condition. Antioxidative and cardiovascular-protective activity of the extract and the purified lichen substances usnic and psoromic acid have been determined.
RESULTS:
Except methanol, all other extracts exhibited antioxidative action in terms of free radical scavenging activity (FRSA) with a half-inhibiting concentration (IC) value of 22.86 to 25.0 µg/mL, nitric oxide radical scavenging activity (NORSA) 141.3 to 149.1 µg/mL and for lipid peroxidation inhibition (LPI) 125 to 157.9 µg/mL. Usnic acid or psoromic acid showed antioxidative action with IC values ranging from 0.174 to 0.271 mg/mL. Methanol and ethyl acetate extract showed hydroxy-3-methyl-glutaryl-CoA reductase (HMGR) inhibition of 65.18 to 74.81%. Only 43.47% inhibition of angiotensin converting enzyme (ACE) was shown by methanol extract. Usnic acid showed noncompetitive type of HMGR inhibition and uncompetitive type of ACE inhibition. Psoromic acid exhibited competitive type of HMGR inhibition and mixed type of ACE inhibition.
DISCUSSION:
U. complanata showed both cardiovascular-protective and antioxidant properties. The lichen species U. complanata may be a natural bioresource for possible pharmaceutical applications....(more)
Behera BC, et al. Pharm Biol 2012 Aug;50(8):968-79.
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- 25. Development of thallus axes in Usnea longissima (Parmeliaceae, Ascomycota), a fruticose lichen showing diffuse growth.
PREMISE OF THE STUDY:
While cell wall thickening in plants is generally associated with tissue maturation, fungal tissues in at least two lichens continue to grow extensively while accumulating massively thickened cell walls. We examined Usnea longissima to determine how diffuse growth shapes morphological and anatomical development of thallus axes and how the highly thickened cell walls of the central cord behave in diffuse growth.
METHODS:
Fresh material was examined with light and epifluorescence microscopy and conventional and low-temperature SEM. Fixed material was embedded in Spurr's resin, microtome-sectioned, and examined with TEM and light microscopy.
KEY RESULTS:
Main axes consisted essentially of bare medullary cord tissue; their characteristic morphology developed by destruction of the overlying cortex and consequent stimulation of lateral branch formation. Fungal cells of the cord tissue continually deposited wall layers of electron-transparent substances and layered, electron-dense materials that include UV-epifluorescent components. Discontinuities were evident in the outermost layers; new branch cells grew through wall materials accumulated by older neighboring cells.
CONCLUSIONS:
Sustained diffuse growth of cord tissue in U. longissima underlies the structural transformation of a corticated thallus branch into a long axis. In the cord tissue, diffuse growth may be responsible for the increasingly disrupted appearance of the older, electron-dense cell wall layers, while new wall materials are laid down adjacent to the protoplast. Cell and tissue development appeared comparable to that observed previously in Ramalina menziesii, although accumulation of wall material was somewhat less extensive and with a greater proportion of electron-dense/UV-epifluorescent components....(more)
Sanders WB, et al. Am J Bot 2012 Jun;99(6):998-1009.
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- 26. Bioindication of volatile elements emission by the Puyehue-Cordón Caulle (North Patagonia) volcanic event in 2011.
The emission of volatile pollutants from the volcanic eruption of the Puyehue-Cordón Caulle complex (North Patagonia Andean Range) that started in June 4th, 2011, was investigated by bioindication means with the epyphytic fruticose lichen Usnea sp. The elemental composition of pooled samples made up with 10 lichen thalli were analysed by Instrumental Neutron Activation Analysis. Eleven sampling sites were selected within the impacted region at different distance from the volcanic source. Five sites were selected as they were already sampled in a previous study prior to the eruption. Two other new sampling sites were selected from outside the impacted zone to provide non-impacted baseline sites. The elements associated with the lichen incorporation of particulate matter (PM) of geological origin were identified by linear correlation with a geochemical tracer (Sm concentrations). The elements associated with PM uptake were Ce, Eu, Fe, Hf, La, Lu, Na, Nd, Sb, Sc, Se, Ta, Tb, Th, U, and Yb. Arsenic and Cs concentrations showed contributions exceeding the PM fraction in sites near the volcanic centre, also higher than the baseline concentrations, which could be associated with permanent emissions from the geothermal system of the Puyehue-Cordón Caulle complex. The lichen concentrations of Ba, Ca, Co, Hg, K, Rb, Sr, and Zn were not associated with the PM, not showing higher concentrations in the sites nearby the volcanic source or respect to the baseline values either. Therefore, there is no indication of the emission of volatile forms of these elements in the lichen records. The lichen records only identified Br volatile emissions associated with the Puyehue-Cordón Caulle complex eruption in 2011.
Copyright © 2012 Elsevier Ltd. All rights reserved....(more)
Bubach D, et al. Chemosphere 2012 Jul;88(5):584-90.
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- 27. Diffractaic acid, a novel proapoptotic agent, induces with olive oil both apoptosis and antioxidative systems in Ti-implanted rabbits.
Usnea longissima Ach., a lichen species, is a traditional herbal medicine with anti-detrimental effects. We evaluated the in vivo effects of a major constituent of U. longissima, diffractaic acid, and the main fatty component of the Mediterranean diet, olive oil, against apoptosis, including various caspase activations and oxidative injury in surrounding tissues after titanium implantation in rabbit femurs. Furthermore, we evaluated the underlying molecular mechanisms. In this study, this lichen metabolite and olive oil activated caspase-dependent cell death with apoptotic morphology, which is distinctly different from necrosis. Both orally and locally administered olive oil and diffractaic acid exerted pro-apoptotic induction in tissues surrounding the implants in titanium-implanted rabbits through the activation of initiator caspases (Cas-2, -8 and -9) and executioner caspase (Cas-3). In addition, they displayed strong myeloperoxidase and inducible nitric oxide synthase activities, providing an alleviating effect. Furthermore, administrations of diffractaic acid and olive oil attenuated the Ti-alloy implantation, and decreased superoxide dismutase activity and total glutathione level in peri-implant tissues. These results demonstrate that diffractaic acid and olive oil are involved in the induction of apoptotic cell death both through caspase-dependent cell death and as an antioxidant. Thus, the data suggest that both diffractaic acid and olive oil could be developed as effective proapoptotic agents in various disorders treatments.
Copyright © 2011 Elsevier B.V. All rights reserved....(more)
Odabasoglu F, et al. Eur J Pharmacol 2012 Jan 15;674(2-3):171-8.
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- 28. Glycyrrhetinic acid inhibits Porphyromonas gingivalis lipopolysaccharide-induced vascular permeability via the suppression of interleukin-8.
OBJECTIVE:
Porphyromonas gingivalis is a major periodontopathogen that plays a role in the pathogenesis of periodontal disease. In this study, we investigated the effect of 18alpha-glycyrrhetinic acid (18α-GA), a natural triterpenoid compound derived from licorice root extract, on P. gingivalis lipopolysaccharide (LPS)-induced vascular permeability, which is a hallmark of inflammatory diseases such as periodontitis.
METHODS:
The inhibitory effects of 18α-GA on endothelial permeability were determined by measuring in vivo and in vitro endothelial permeability. Endothelial cells were pretreated with 18α-GA before exposure to P. gingivalis LPS, and total RNA or proteins were extracted and analyzed by reverse transcription polymerase chain reaction or western blotting.
RESULTS:
Porphyromonas gingivalis LPS-induced endothelial permeability was significantly inhibited by 18α-GA both in vivo and in vitro. 18α-GA reduces P. gingivalis LPS-induced gap formation of endothelial cells. Importantly, 18α-GA modulated the expression and secretion of interleukin-8 (IL-8), a key inducer of vascular permeability, by downregulating nuclear factor-κB (NF-κB). 18α-GA suppressed P. gingivalis LPS-stimulated inhibitor of kappa B (IκB) kinase activation, IκBα phosphorylation, and nuclear translocation of NF-κB.
CONCLUSIONS:
Overall, these findings suggest that 18α-GA significantly reduces P. gingivalis LPS-induced vascular permeability by repressing NF-κB-dependent endothelial IL-8 production, suggesting its therapeutic potential in P. gingivalis-related vascular diseases....(more)
Kim SR, et al. Inflamm Res 2013 Feb;62(2):145-54.
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- 29. The efficacy of licorice root extract in decreasing transaminase activities in non-alcoholic fatty liver disease: a randomized controlled clinical trial.
This study was performed to investigate the effects of licorice on non-alcoholic fatty liver disease (NAFLD). In this double blind randomized clinical trial, 66 patients were divided into case and control groups. All patients had elevated liver enzymes and had increased liver echogenicity (lipid accumulation) on sonography. The case group was treated with one capsule containing 2 g aqueous licorice root extract per day for 2 months while the control group was treated in the same manner with a placebo. Weight, body mass index (BMI) and liver transaminase levels were measured for each patient before and after the study. In the case group, the mean alanine aminotransferase (ALT) level decreased from 64.09 to 51.27 IU/mL and the aspartate aminotransferase (AST) level decreased from 58.18 to 49.45 IU/mL, which were statistically significant (p < 0.001 and p < 0.001). But in the control group, a drop in the ALT and AST levels was not statistically significant. The BMI difference before and after the study was not statistically significant in both groups. Despite the significant drop in liver enzymes following administration of licorice root extract, it is recommended that further studies that include histological examination are necessary....(more)
Hajiaghamohammadi AA, et al. Phytother Res 2012 Sep;26(9):1381-4.
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- 30. The antimicrobial effects of deglycyrrhizinated licorice root extract on Streptococcus mutans UA159 in both planktonic and biofilm cultures.
The objective of the study was to investigate the antimicrobial effects of deglycyrrhizinated licorice root extracts (DG-LRE) against Streptococcus mutans UA159 in both the planktonic and biofilm phases by determining the minimum inhibitory concentration and minimum bactericidal concentration, and by performing time-kill kinetic, growth, adhesion, and biofilm assays. The cell toxicity of DG-LRE on normal human gingival fibroblast (NHGF) cells was tested using a methyl thiazolyl tetrazolium assay. This study showed that DG-LRE had strong antimicrobial activity against S. mutans in the planktonic phase with little cytotoxic effect on NHGF cells. In addition, DG-LRE significantly inhibited biofilm formation by S. mutans UA159 at concentrations over 4 μg/ml for glucose or 16 μg/ml for sucrose, respectively, regardless of the presence of saliva-coating. To the best of our knowledge, this is the first report to provide evidence that DG-LRE demonstrates antimicrobial activity against S. mutans. These results suggest that DG-LRE can be used in developing oral hygiene products, such as gargling solution and dentifrice to prevent human dental caries....(more)
Ahn SJ, et al. Anaerobe 2012 Dec;18(6):590-6.
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- 31. Protective effects of glycyrrhizin against β?-adrenergic receptor agonist-induced receptor internalization and cell apoptosis.
It has been reported that treatment with β adrenergic receptor (βAR) agonist bronchodilators may result in airway βARs internalization and cardiac muscle cells apoptosis. This could lead to the loss of pharmacological effect of βAR agonists and increase adverse cardiovascular events in asthma patients receiving βAR agonist therapy. Glycyrrhizin, the major bioactive component of licorice root extract, has been reported to exhibit protective effect on respiratory system. Here, we investigate the effects of glycyrrhizin against βAR agonist salbutamol-induced receptor internalization and cell apoptosis. In our study, the live cell confocal imaging and fixed-cell enzyme-linked immunosorbent assay (ELISA) assay revealed that glycyrrhizin significantly inhibited salbutamol-induced surface βAR internalization. The underlying mechanisms were then identified to be that glycyrrhizin could reduce the association of βARs with β-arrestins and clathrin heavy chain as well as the level of G protein-coupled receptor kinase (GRK) mediated phosphorylation of βARs. The inhibition of receptor internalization by glycyrrhizin further lead to stabilization of the βAR mRNA and protein expression, thus amplified the transmembrane signaling via the βARs. We also proved that glycyrrhizin could profoundly attenuate salbutamol-induced early cellular apoptosis by regulating the expressions of B-cell lymphoma 2 (Bcl-2) family genes. Taken together, our results suggest that glycyrrhizin exhibits protective effects against βAR agonist-induced receptor internalization and cell apoptosis. These findings might have practical implications for future strategies of combined application of glycyrrhizin with βAR receptor agonists to improve the efficacy of bronchodilators in patients with asthma and chronic obstructive pulmonary disease (COPD)....(more)
Shi Q, et al. Biol Pharm Bull 2011;34(5):609-17.
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- 32. Antiviral effect of diammonium glycyrrhizinate and lithium chloride on cell infection by pseudorabies herpesvirus.
Diammonium glycyrrhizin (DG), a salt from glycyrrhizinate (GL) that is a major active component of licorice root extract with various pharmacological activities was investigated for its inhibitory effect on pseudorabies virus (PrV) infection. In parallel, lithium chloride (LiCl), a chemical reagent with potential antiviral activity was compared with DG for their inhibitory ability against PrV infection in vitro. Virus plaque-reduction assays, PCR and RT-PCR analysis indicated that both drugs inhibited cell infection by PrV. Moreover, addition of the drugs resulted in fewer apoptotic cells during PrV infection....(more)
Sui X, et al. Antiviral Res 2010 Feb;85(2):346-53.
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- 33. 18Beta-glycyrrhetinic acid ameliorates acute Propionibacterium acnes-induced liver injury through inhibition of macrophage inflammatory protein-1alpha.
18Beta-glycyrrhetinic acid (GA), the major bioactive component of licorice root extract, has a protective effect on hepatic injury and exhibits antiinflammatory activity. Here, we investigate the effect of GA in Propionibacterium acnes-induced acute inflammatory liver injury. C57BL/6 mice were primed with P. acnes followed by lipopolysaccharide challenge to induce fulminant hepatitis. GA (75 mg/kg) or vehicle control was administered intraperitoneally daily 1 day after P. acnes priming, and GA significantly improved mouse mortality. Then, to investigate the underlying mechanisms of GA in this acute inflammatory liver injury model, we primed C57BL/6 mice with P. acnes only. We propose that GA ameliorates acute P. acnes-induced liver injury through reduced macrophage inflammatory protein (MIP)-1alpha expression in Kupffer cells by down-regulating MyD88 expression and inhibiting NF-kappaB activation. Reduced MIP-1alpha expression lowered the recruitment of CD11c(+)B220(-) dendritic cell precursors into the liver. Consequently, GA treatment inhibits the activation and proliferation of liver-infiltrating CD4(+) T cells and reduces the production of serum alanine aminotransferase and proinflammatory cytokines such as interferon-gamma and tumor necrosis factor-alpha. Moreover, anti-MIP-1alpha treatment in P. acnes-primed mice inhibits the recruitment of dendritic cell precursors into the liver and suppresses mouse mortality as GA does. Taken together, our results suggest that GA exhibits antiinflammatory effects through inhibition of MIP-1alpha in a mouse model of acute P. acnes-induced inflammatory liver injury....(more)
Xiao Y, et al. J Biol Chem 2010 Jan 8;285(2):1128-37.
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- 34. 18β-glycyrrhetinic acid inhibits periodontitis via glucocorticoid-independent nuclear factor-κB inactivation in interleukin-10-deficient mice.
BACKGROUND AND OBJECTIVE:
18β-Glycyrrhetinic acid (GA) is a natural anti-inflammatory compound derived from licorice root extract (Glycyrrhiza glabra). The effect of GA on experimental periodontitis and its mechanism of action were determined in the present study.
MATERIAL AND METHODS:
Periodontitis was induced by oral infection with Porphyromonas gingivalis W83 in interleukin-10-deficient mice. The effect of GA, which was delivered by subcutaneous injections in either prophylactic or therapeutic regimens, on alveolar bone loss and gingival gene expressions was determined on day 42 after initial infection. The effect of GA on lipopolysaccharide (LPS)-stimulated macrophages, T cell proliferation and osteoclastogenesis was also examined in vitro.
RESULTS:
18β-Glycyrrhetinic acid administered either prophylactically or therapeutically resulted in a dramatic reduction of infection-induced bone loss in interleukin-10-deficient mice, which are highly disease susceptible. Although GA has been reported to exert its anti-inflammatory activity via downregulation of 11β-hydroxysteroid dehydrogenase-2 (HSD2), which converts active glucocorticoids to their inactive forms, GA did not reduce HSD2 gene expression in gingival tissue. Rather, in glucocorticoid-free conditions, GA potently inhibited LPS-stimulated proinflammatory cytokine production and RANKL-stimulated osteoclastogenesis, both of which are dependent on nuclear factor-κB. Furthermore, GA suppressed LPS- and RANKL-stimulated phosphorylation of nuclear factor-κB p105 in vitro.
CONCLUSION:
These findings indicate that GA inhibits periodontitis by inactivation of nuclear factor-κB in an interleukin-10- and glucocorticoid-independent fashion.
© 2010 John Wiley & Sons A/S....(more)
Sasaki H, et al. J Periodontal Res 2010 Dec;45(6):757-63.
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- 35. Prevention of free fatty acid-induced hepatic lipotoxicity by 18beta-glycyrrhetinic acid through lysosomal and mitochondrial pathways.
Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease and affects millions of people worldwide. Despite the increasing prevalence of NAFLD, the exact molecular/cellular mechanisms remain obscure and effective therapeutic strategies are still limited. It is well-accepted that free fatty acid (FFA)-induced lipotoxicity plays a pivotal role in the pathogenesis of NAFLD. Inhibition of FFA-associated hepatic toxicity represents a potential therapeutic strategy. Glycyrrhizin (GL), the major bioactive component of licorice root extract, has a variety of pharmacological properties including anti-inflammatory, antioxidant, and immune-modulating activities. GL has been used to treat hepatitis to reduce liver inflammation and hepatic injury; however, the mechanism underlying the antihepatic injury property of GL is still poorly understood. In this report, we provide evidence that 18 beta-glycyrrhetinic acid (GA), the biologically active metabolite of GL, prevented FFA-induced lipid accumulation and cell apoptosis in in vitro HepG2 (human liver cell line) NAFLD models. GA also prevented high fat diet (HFD)-induced hepatic lipotoxicity and liver injury in in vivo rat NAFLD models. GA was found to stabilize lysosomal membranes, inhibit cathepsin B expression and enzyme activity, inhibit mitochondrial cytochrome c release, and reduce FFA-induced oxidative stress. These characteristics may represent major cellular mechanisms, which account for its protective effects on FFA/HFD-induced hepatic lipotoxicity. CONCLUSION: GA significantly reduced FFA/HFD-induced hepatic lipotoxicity by stabilizing the integrity of lysosomes and mitochondria and inhibiting cathepsin B expression and enzyme activity....(more)
Wu X, et al. Hepatology 2008 Jun;47(6):1905-15.
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