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Evaluation of hepatoprotective activity of Ginkgo biloba in rats.

The mechanism of hepatoprotective effects of Ginkgo biloba (GB), an herbal preparation with wide variety of therapeutic application, on paracetamol (Pcml) induced hepatic damage in rats has been investigated. GB treatment restored the marker enzyme levels indicating the in vivo protective effects against Pcml induced liver damage both in preventive and curative aspects. GB also reversed the increased TBARS levels, and elevated the GSH content of the liver. The results obtained from the study indicate hepatoprotective nature of GB, which might be due to its ability to prevent lipid peroxidation and replenishing the gllutathione level. The effects of GB were comparable to that of silymarin.

Animals↗

[Optimization of the solvent system in thin-layer chromatography (TLC)].

Much effort in TLC has been devoted to optimization methods of solvent system in order to get best separation of components. Various optimization methods have been established, but the universality of some methods was poor. They were only applicable to samples of known components. This paper reports a complex method. When the complexity of the solvent system was determined, uniform design was used to arrange experiments, the data obtained from scanning chromatogram were input computer to get regression equation. The precision of the regression equation should be judged at first. If the precision was proper, the regression equation could be input the program of the complex method to obtain the composition of the solvent system. Optimization results were dichloroethane-benzene-methanol (4.81:4.42:0.78) for cortical hormone; toluene-ethanol-dichloroethane-trichloromethane (2.30:1.46:3.32:2.92) for sulfa drugs and trichloromethane-methanol-ethyl acetate (3.30:3.29:3.41) for ginkgo biloba. Then the verification experiment was made. The verifying test showed that the experimental results are identical with the calculated ones.

Chloroform↗

Isolation of RNA of high quality and yield from Ginkgo biloba leaves.

An improved protocol was developed to isolate total RNA in good yield and integrity from Ginkgo biloba leaves containing high levels of flavonoid glycosides, terpene lactones, carbohydrates and polyphenolic secondary metabolites. Polyvinylpolypyrrolidone at 2% and beta-mercaptoethanol at 4% were added to the standard CTAB extraction buffer and, after chloroform and phenol extraction, the pellet obtained by ethanol/acetate precipitation was washed and a second phenol/chloroform extraction was introduced to remove co-precipitated polysaccharides. Both A(260)/A(230) and A(260)/A(280) absorbancy ratios of isolated RNA were around 2 and the yield was about 0.4 mg g(--1) fresh weight. At least seven distinct rRNA bands were detected by denaturing gel electrophoresis. Sharp hybridization signals were obtained from Northern blots with both nuclear and plastid gene probes. Two gene fragments: nuclear-encoded cab and chloroplast encoded rbcL were successfully amplified by RT-PCR, suggesting the integrity of isolated RNA. The total RNA isolated by this protocol is of sufficient quality for subsequent molecular applications.

Acetates↗

Pre-exposure to a novel nutritional mixture containing a series of phytochemicals prevents acetaminophen-induced programmed and unprogrammed cell deaths by enhancing BCL-XL expression and minimizing oxidative stress in the liver.

From a disease-prevention perspective, recent progress in phytochemical and nutraceutical research clearly suggests (benefits outweigh the risk pattern). Although powerful antioxidant properties have been the most acclaimed mechanism of action for these entities, the individual antioxidants studied in clinical trials do not appear to have consistent preventative effects. The actions of the antioxidant nutrients alone do not explain the observed health benefits of diets rich in fruits and vegetables for chronic diseases. Therefore, we proposed that the additive and synergistic effects of phytochemicals in fruits and vegetables are responsible for these potent antioxidant and anticancer activities, and that the benefit of a diet rich in fruits and vegetables is attributed to the complex mixture of phytochemicals present in plants [1]. Surprisingly, however, no studies have attempted to evaluate the combined antitoxic potential of a phytochemical-nutraceutical mixture (PNM) in in vivo models. Therefore, this study, for the first time, was designed to investigate whether pre-exposure to a unique PNM has the ability to impede mechanistic events involved in acetaminophen (APAP)-induced hepatotoxicity. Besides several vitamins and minerals in balanced proportions (approximately US RDA), the PNM used in this investigation contained several well-known phytochemicals such as citrus flavonoids, red wine polyphenols, Garcinia, Gymnema, Ginkgo, Ephedra sinica, Camellia sinensis, Silybum, Guarana, Eluthero, Allium sativum and Ocimum basilicum extracts. To evaluate PNM's antitoxic potential, groups of animals ICR mice, 3 months old) received either a control diet or PNM containing diets (1X and 10X) for 4 weeks. On day-28, animals were divided into two subgroups. Half the animals were administered normal saline and the other half received 400mg/kg ip injections of APAP. All the animals were sacrificed 24h after APAP exposure. Serum and tissue (liver and kidneys) samples were analyzed. APAP alone caused massive liver injury (nearly 495-fold increase in ALT) and oxidative stress (Lipid peroxidation: 268% increase in MDA) coupled with genomic DNA fragmentation (288% increase). Exposure to 1X-PNM for 28 days significantly reduced animal mortality and all the APAP-induced biochemical events (In 1X-PNM + AP: ALT leakage decreased to 54 fold; MDA accumulation decreased to 125%, and DNA fragmentation decreased to 122%), whereas 10X-PNM + APAP slightly escalated both oxidative stress and genomic DNA fragmentation preceding liver injury. Liver homogenates subjected to western blot analysis disclosed the ability of 1X-PNM to counteract APAP-induced decrease in Bcl-xL expression. Histopathological evaluation of stained liver tissue sections indicated anti-apoptogenic and anti-necrogenic reponses coupled with near complete prevention of glycogen depletion by 1X-PNM. Collectively, our investigation suggests that a mixture containing an assortment of phytochemicals/nutraceuticals may serve as a much more powerful blend in preventing drug or chemical-induced organ injuries than a single phytochemical or nutraceutical entity. In addition, ephedra and caffeine containing PNM-exposure in a controlled manner may potentially shield vital target organs from toxicities caused by intentional, unintentional or accidental exposures to structurally and functionally diverse drug and chemical entities.

Acetaminophen↗

Mood-enhancing antidepressant St. John's wort inhibits the activation of human immunodeficiency virus gene expression by ultraviolet light.

Ultraviolet (UV) radiation is a potent activator of the human immunodeficiency virus (HIV) gene expression in a HeLa cell clone with stably integrated copies of the HIVcat reporter construct. Recently, we have shown that activation of p38 MAP kinase and NF-kappaB is necessary but not sufficient for triggering efficient HIV gene expression in response to UV. Here we demonstrate that St. John's wort is a potent inhibitor of the UV-induced activation of HIV gene expression in HeLa cells. Stably transfected HIVcat/HeLa cells were preincubated with different amounts (25-100 microl) of St. John's wort or gingko biloba extracts for 30 min, then irradiated with UV (30 J/m2). In contrast to ginkgo biloba, St. John's wort inhibited the UV-induced HIV gene expression in a dose-dependent manner. Furthermore, preincubation with St. John's wort (10, 20, and 30 microl) for 30 min before UV (30 J/m2) irradiation, PMA- and UV-induced NF-kappaB activation was completely blocked, whereas ginkgo biloba did not affect the PMA- and UV-induced NF-kappaB activation in HeLa cells. UV activation of p38 MAP kinase was not inhibited by St. John's wort or by ginkgo biloba. However, we found that p38 MAP kinase and JNK1 and -2 were activated by St. John's wort, but p44/42 MAP kinase was not activated by St. John's wort in HeLa cells. Hypericin an active ingredient in St. John's wort also inhibited the UV activation of HIV gene expression in HeLa cells. These results firmly confirm that St. John's wort is a potent inhibitor of the UV-induced activation of HIV gene expression in HeLa cells.

Anthracenes↗

Altered oral absorption of alcohol by combined aqueous extracts of four herbal plants in rats.

This study examined the effect of combined aqueous extracts (BHR) of Ginko biloba, Mentha arvensis var. piperascens, Citrus unshiu, and Pueraria lobata var. chinensis on oral absorption of alcohol in rats. The rats were pretreated with BHR, placebo solution identical to BHR without the herbal extract, and isotonic saline. Alcohol was administered orally at 1- and 3-g/kg doses and the absorption profiles were compared. After oral administration of 1-g/kg doses, mean area under the curve (AUC) and C(max) values were significantly reduced in BHR-treated rats (16.1 +/- 10.0 and 0.3 +/- 0.1 mg/ml, respectively) as compared with saline-treated (37.9 +/- 14.4 and 0.7 +/- 0.7 mg/ml, respectively) and placebo solution-treated (63.0 +/- 46.4 and 0.7 +/- 0.4 mg/ml, respectively) rats. Similarly, after administration of 3-g/kg doses, mean AUC and C(max) values in BHR-treated rats (188.1 +/- 119.7 mg(.)min/ml and 1.0 +/- 0.4 mg/ml) were significantly reduced over those in saline-treated rats (571.4 +/- 512.4 mg(.)min/ml and 1.8 +/- 0.9 mg/ml, respectively). The relative oral bioavailability of alcohol calculated as the ratio of AUC(BHR)/AUC(Saline) was 42.5% and 32.9% at 1- and 3-g/kg doses, respectively. The reduced serum alcohol levels as well as the reduced AUC and C(max) after pretreatment with BHR appear to be a result of a reduced systemic absorption not due to an increased metabolic clearance.

Animals↗

Effects of Gingko biloba extract on gap junction changes induced by reperfusion/reoxygenation after ischemia/hypoxia in rat brain.

Gap junction communication between astrocytes plays an important role in the brain. The purpose of this study was to investigate the effects of Gingko biloba extract (GBE) on the changes of connexin 43 (Cx43) mRNA and protein expression levels of rat cortex and hippocampus induced by ischemia-reperfusion and astrocyte gap junction intercellular communication (GJIC) induced by hypoxia-reoxygenation. After 2 hours of middle cerebral artery occlusion (MCAO) followed by 24 hours of reperfusion, there was obvious neurological deficit in rats. Cx43 mRNA and protein expression levels of rat cortex and hippocampus in the ischemia hemisphere were decreased significantly. When GBE at doses of 50 and 100 mg/kg body weight was administrated by p.o. daily for 7 days, the neurological deficit was improved, and lower Cx43 mRNA and protein expression levels induced by ischemia-reperfusion were recovered to normal. The i.p. injection of nimodipine (0.7 mg/kg weight body) also showed improvement on neurological deficit and Cx43 expression levels. Astrocyte GJIC was measured by the fluorescence recovery after photobleaching (FRAP). Hypoxia-reoxygenation induced a significant decrease in GJIC. Pretreatment with GBE (100 mg/l) and nimodipine (1.6 mg/l) significantly prevented the hypoxia-reoxygenation inhibition of GJIC. These results suggest that GBE could exert its neuroprotective effects by improvement of Cx43 expression and GJIC induced by hypoxia/ischemia-reoxygenation/ reperfusion injury.

Animals↗

Cloning and characterization of a flavanone 3-hydroxylase gene from Ginkgo biloba.

Flavanone 3-hydroxylase (F3H) activity is necessary for the biosynthesis of flavonoids, the main ingredients of Gingko biloba extract. The full-length cDNA and genomic DNA sequences of F3H gene were isolated from G. biloba for the first time. The full-length cDNA of G. biloba F3H gene (designated as GbF3H) contained a 1071 bp open reading frame (ORF) encoding a 357-amino-acid protein with a calculated molecular weight of about 40 kDa and isoelectric point (pI) of 5.57. The genomic DNA analysis showed that GbF3H gene had three exons and two introns. The deduced GbF3H protein showed high identities to other plant F3Hs. The conserved amino acids ligating ferrous iron and residues participating in 2-oxoglutarate binding (R-X-S) were found in GbF3H at the similar positions like other F3Hs. Three-dimensional structure modeling showed that GbF3H had a jerry roll in the enzyme core consisted of beta-sheet, a typical structure shared by all 2-oxoglutarate-dependent dioxygenases including F3Hs. Phylogenetic tree analysis revealed that GbF3H shared the same ancestor in evolution with other F3Hs and had a further relationship with other angiosperms species. Southern blot analysis indicated that GbF3H belonged to a multi-gene family. Transcription analysis revealed that GbF3H expressed in stem and leaf with the highest transcription level in leaf. The isolation and characterization of GbF3H gene will be helpful to further study the role of GbF3H gene in the biosynthesis of flavonoids in G. biloba.

Amino Acid Sequence↗

Changes in N-linked oligosaccharides during seed development of Ginkgo biloba.

Structural changes in N-linked oligosaccharides of glycoproteins during seed development of Ginkgo biloba have been explored to discover possible endogenous substrate(s) for the Ginko endo-beta-N-acetylglucosaminidase (endo-GB; Kimura, Y., et al. (1998) Biosci. Biotechnol. Biochem., 62, 253-261), which should be involved in the production of high-mannose type free N-glycans. The structural analysis of the pyridylaminated oligosaccharides with a 2D sugar chain map, by ESI-MS/MS spectroscopy, showed that all N-glycans expressed on glycoproteins through the developmental stage of the Ginkgo seeds have the xylose-containing type (GlcNAc2 approximately 0Man3Xyl1Fuc1 approximately 0GlcNAc2) but no high-mannose type structure. Man3Xyl1Fuc1GlcNAc2, a typical plant complex type structure especially found in vacuolar glycoproteins, was a dominant structure through the seed development, while the amount of expression of GlcNAc2Man3Xyl1Fuc1GlcNAc2 and GlcNAc1Man3Xyl1Fuc1GlcNAc2 decreased as the seeds developed. The dominantly occurrence of xylose-containing type structures and the absence of the high-mannose type structures on Ginkgo glycoproteins were also shown by lectin-blotting and immunoblotting of SDS-soluble glycoproteins extracted from the developing seeds at various developmental stages. Concerning the endogenous substrates for plant endo-beta-N-acetylglucosaminidase, these results suggested that the endogenous substrates might be the dolicol-oligosaccharide intermediates or some glycopeptides with the high-mannose type N-glycan(s) derived from misfolded glycoproteins in the quality control system for newly synthesized glycoproteins.

Carbohydrate Sequence↗

Ginkgo biloba normalises stress-elevated alterations in brain catecholamines, serotonin and plasma corticosterone levels.

Stress and depression and associated mental health problems have increased tremendously in modern times. The search for effective and safe alternatives from natural sources especially plant products should, therefore, continue. Forced immobilization is one of the best explored models of stress in rats and the role of corticosterone, serotonin and catecholamines, i.e. norepinephrine (NE), dopamine (DA) is well documented. Numerous studies have shown that Ginkgo biloba has antioxidant and neuroprotective properties and utility in cerebrovascular insufficiency and impaired cerebral performance. We investigated the effect of G. biloba on whole brain catecholamine, serotonin and plasma corticosterone levels following 1, 2 and 4 h restraint stress using HPLC and also plasma corticosterone using luminescence spectrophotometry. G. biloba extract (14 mg/kg p.o.) restored restraint stress-induced elevation in whole brain levels of catecholamines (NE, DA), 5-HT and plasma corticosterone to near normal levels. Further studies are warranted to explore the clinical potential of this encouraging lead in the management of stress and to elucidate the mechanisms involved.

Animals↗

A review of 12 commonly used medicinal herbs.

A large and increasing number of patients use medicinal herbs or seek the advice of their physician regarding their use. More than one third of Americans use herbs for health purposes, yet patients (and physicians) often lack accurate information about the safety and efficacy of herbal remedies. Burgeoning interest in medicinal herbs has increased scientific scrutiny of their therapeutic potential and safety, thereby providing physicians with data to help patients make wise decisions about their use. This article provides a review of the data on 12 of the most commonly used herbs in the United States. In addition, we provide practical information and guidelines for the judicious use of medicinal herbs.

Chamomile↗

Selective responses of three Ginkgo biloba leaf-derived constituents on human intestinal bacteria.

The selective responses of Ginkgo biloba leaf-derived materials against six intestinal bacteria was examined using an impregnated paper disk method and compared with that of bilobalide, ginkgolides A and B, kaempferol, and quercetin. The components of G. biloba leaves were characterized as kaempferol 3-O-alpha-(6' "-p-coumaroylglucosyl-beta-1,4-rhamnoside), kaempferol 3-O-(2' '-O-beta-D-glucopyranosyl)-alpha-L-rhamnopyranoside, and quercetin 3-O-alpha-(6' "-p-coumaroylglucosyl-beta-1,4-rhamnoside) by spectroscopic analysis. The growth responses varied with each bacterial strain tested. At 2 mg/disk, kaempferol 3-O-alpha-(6' "-p-coumaroylglucosyl-beta-1,4-rhamnoside) and quercetin 3-O-alpha-(6' "-p-coumaroylglucosyl-beta-1,4-rhamnoside) revealed potent inhibition against Clostridium perfringens, and kaempferol 3-O-(2' '-O-beta-D-glucopyranosyl)-alpha-L-rhamnopyranoside showed a clear inhibitory effect on Escherichia coli. At 0.5 mg/disk, quercetin 3-O-alpha-(6' "-p-coumaroylglucosyl-beta-1,4-rhamnoside) showed a strong activity against C. perfringens, but weak activity was exhibited by kaempferol 3-O-alpha-(6' "-p-coumaroylglucosyl-beta-1,4-rhamnoside) against C. perfringens and kaempferol 3-O-(2' '-O-beta-D-glucopyranosyl)-alpha-L-rhamnopyranoside against E. coli. No inhibition was observed from treatments conducted with bilobalide, ginkgolides A and B, kaempferol, or quercetin. Furthermore, these isolated compounds did not inhibit Bifidobacterium bifidum, B. longum, B. adolescentis, or Lactobacillus acidophilus.

Bifidobacterium↗

Apoptosis of hepatoma cells SMMC-7721 induced by Ginkgo biloba seed polysaccharide.

AIM: To study the apoptosis of hepatoma cells SMMC-7721 induced by polysaccharide isolated from Ginkgo biloba seed. METHODS: Ginkgo biloba seed polysaccharide (GBSP) was isolated by ethanol fractionation of Ginkgo biloba seed and purified by Sephadex G-200 chromatography. The purity of GBSP was verified by reaction with iodine-potassium iodide and ninhydrin and confirmed by UV spectrophotometer, cellulose acetate membrane electrophoresis and Sepharose 4B gel filtration chromatography. The Scanning Electron Microscope (SEM) and Flow Cytometry (FCM) were used to examine the SMMC-7721 cells with and without GBSP treatment at 500 mg/ml for 36 h. RESULTS: GBSP product obtained was of high purity with the average molecular weight of 1.86 X 10(5). Quantitative analysis of SMMC-7721 cells in vitro with FCM showed that the percentages of G(2)-M cells without and with GBSP treatment were 17.01+/-1.28 % and 11.77+/-1.50% (P<0.05), the debris ratio of the cells were 0.46+/-0.12 % and 0.06+/-0.06 % (P<0.01), and the apoptosis ratio of cells was 3.84+/-0.55 % and 9.13+/-1.48 % (P<0.01) respectively. Following GBSP treatment, microvilli of SMMC-7721 cells appeared thinner and the number of spherical cells increased markedly. Most significantly, the apoptosis bodies were formed on and around the spherical cells treated with GBSP. CONCLUSION: GBSP could potentially induce the apoptosis of SMMC-7721 cells.

Apoptosis↗

Nutraceuticals: sorting out fact, fiction, and uncertainty.

Scientific evaluation of herbal products has been limited, yet herbal products are the most commonly consumed health care products. Because of known pharmacological effects and potential interactions of many of these compounds with therapeutic drugs, a history of herbal and dietary supplement intake should be considered part of the routine medical history and should be evaluated before any changes in prescription drugs and before medical procedures.

Dietary Supplements↗