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PubMed2003

Taxonomic significance of flavonoid variation in temperate species of Nothofagus.

Forty-two flavonoids and a stilbene (pinosylvin) were identified in the leaf exudates of 11 temperate species of Nothofagus from South America, Australia and New Zealand. The flavonoid profiles demonstrate significant taxonomic value at the subgeneric level. Most species of subgenus Fuscospora are characterized by the presence of pinosylvin, galangin and galangin methyl ethers. Kaempferol-type flavonols are abundant in subgenus Lophozonia while these flavonols are largely absent from species of subgenus Fuscospora. The flavonoid patterns are largely in agreement with a recent subgeneric classification of Nothofagus.

Cluster Analysis↗
PubMed2002

Carbon-14 biolabelling of wine polyphenols in Vitis vinifera cell suspension cultures.

14C-L-phenylalanine is incorporated into a range of polyphenolic compounds when fed to grape cell cultures. Optimisation of several parameters such as the quantity of precursor applied and the duration of metabolism led to incorporation yields of 15% and to specific activities of 875 mu Ci g(-1) in stilbenes. Purification of the products by several chromatographic steps is reported. Both trans- and cis-resveratrols were easily obtained by enzymatic hydrolysis of their corresponding glucosides, with specific activity of 1200-1400 mu Ci g(-1). The specific radioactivity obtained for all the compounds is suitable for in vivo feeding trials to trace their metabolic fate when consumed by animals and for in vitro activity mechanism studies. Indeed, these polyphenols seem to be implicated in the health benefits associated with regular and moderate wine consumption but little is known about their pharmacokinetics and cellular uptake.

Anthocyanins↗
PubMed2000

DNA breakage by resveratrol and Cu(II): reaction mechanism and bacteriophage inactivation.

Resveratrol (3,4',5-trihydroxy stilbene) is a phytoalexin and a polyphenolic compound present in human dietary material such as peanuts, mulberries, grapes and red wine. It is widely considered to possess cardiovascular protective properties and has also been shown to be chemopreventive against various stages of chemically induced carcinogenesis. It has recently been shown that resveratrol induces strand breakage in DNA in the presence of copper ions. In this paper, we have shown that resveratrol catalyzes the reduction of Cu(II) to Cu(I), which is accompanied by the formation of 'oxidized product(s)' of resveratrol, which in turn also appear to catalyze the reduction of Cu(II). Strand scission by the resveratrol-Cu(II) system was found to be biologically active as assayed by bacteriophage inactivation. The results are discussed in relation to the putative chemopreventive mechanism of resveratrol.

Animals↗
PubMed1998

Effects of resveratrol on 12-O-tetradecanoylphorbol-13-acetate-induced oxidative events and gene expression in mouse skin.

Resveratrol (3,5,4'-trihydroxy-trans-stilbene) is a natural product shown to inhibit carcinogen-induced pre-neoplastic lesions in mouse mammary organ culture and 12-O-tetradecanoylphorbol-13-acetate (TPA)-promoted mouse skin tumors. Application of TPA to mouse skin induces oxidative stress, as evidenced by numerous biochemical responses, including significant generation of H2O2 and enhanced levels of myeloperoxidase and oxidized glutathione reductase activities and decreases in glutathione levels and superoxide dismutase activity. TPA treatment also elevates the expression of cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), c-myc, c-fos, c-jun, transforming growth factor-beta1 (TGF-beta1) and tumor necrosis factor-alpha (TNF-alpha). As currently reported, pre-treatment of mouse skin with resveratrol negated several of these TPA-induced effects in a dose-dependent manner. H2O2 and glutathione levels were restored to control levels, as were myeloperoxidase, oxidized glutathione reductase and superoxide dismutase activities. As judged by reverse transcriptase-polymerase chain reaction (RT-PCR), TPA-induced increases in the expression of c-fos and TGF-beta1 were selectively inhibited. These data suggest that resveratrol inhibits tumorigenesis in mouse skin through interference with pathways of reactive oxidants and possibly by modulating the expression of c-fos and TGF-beta1.

Animals↗
PubMed1999

Resveratrol, an antioxidant present in red wine, induces apoptosis in human promyelocytic leukemia (HL-60) cells.

Resveratrol, a triphenolic stilbene present in grapes and other plants, has striking antioxidant and anti-inflammatory activities which have been considered to be responsible for the beneficial effects of red wine consumption on coronary heart disease. Recent studies reveal that resveratrol can inhibit each step of multistage carcinogenesis. However, the molecular mechanisms underlying anti-tumorigenic or chemopreventive activities of this phytochemical remain largely unknown. In the present work, we have found that resveratrol reduces viability and DNA synthesis capability of cultured human promyelocytic leukemia (HL-60) cells. The growth inhibitory and antiproliferative properties of resveratrol appear to be attributable to its induction of apoptotic cell death as determined by morphological and ultrastructural changes, internucleosomal DNA fragmentation, and increased proportion of the subdiploid cell population. Resveratrol treatment resulted in a gradual decrease in the expression of anti-apoptotic Bcl-2. These results, together with previous findings, suggest the cancer therapeutic as well as chemopreventive potential of resveratrol.

Anticarcinogenic Agents↗
PubMed2002

Constituents of Gnetum montanum.

A new stilbene, gnetifolin M (1), was isolated from the lianas of Gnetum montanum, together with seven known compounds, resveratrol (2), gnetol (3), 4', 5,7-trihydroxy-3'-methoxyflavone, beta-sitosterol, daucosterol, ursolic acid, and tetracosanoic acid. The structure of 1 was determined to be 2-(5'-methoxy-3'-hydroxyphenyl)-4-hydroxybenzofuran on the basis of spectroscopic evidence.

Benzofurans↗
PubMed2002

Resveratrol and cancer: a review.

The various properties of the stilbene phytoalexin Resveratrol provide interesting new avenues of research in the field of chemoprevention and chemotherapy. A particular emphasis is given on xenobiotic-related carcinogenesis.

Antineoplastic Agents, Phytogenic↗
PubMed2003

Protective effect of resveratrol on beta-amyloid-induced oxidative PC12 cell death.

Beta-amyloid peptide is considered to be responsible for the formation of senile plaques that accumulate in the brains of patients with Alzheimer's disease. There has been compelling evidence supporting the idea that beta-amyloid-induced cytotoxicity is mediated through the generation of reactive oxygen intermediates (ROIs). Considerable attention has been focused on identifying phytochemicals that are able to scavenge excess ROIs, thereby protecting against oxidative stress and cell death. Resveratrol (3,5,4'-trihydroxy-trans-stilbene), a phytoalexin found in the skin of grapes, has strong antioxidative properties that have been associated with the protective effects of red wine consumption against coronary heart disease ("the French paradox"). In this study, we have investigated the effects of resveratrol on beta-amyloid-induced oxidative cell death in cultured rat pheochromocytoma (PC12) cells. PC12 cells treated with beta-amyloid exhibited increased accumulation of intracellular ROI and underwent apoptotic death as determined by characteristic morphological alterations and positive in situ terminal end-labeling (TUNEL staining). Beta-amyloid treatment also led to the decreased mitochondrial membrane potential, the cleavage of poly(ADP-ribose)polymerase, an increase in the Bax/Bcl-X(L) ratio, and activation of c-Jun N-terminal kinase. Resveratrol attenuated beta-amyloid-induced cytotoxicity, apoptotic features, and intracellular ROI accumulation. Beta-amyloid transiently induced activation of NF-kappaB in PC12 cells, which was suppressed by resveratrol pretreatment.

Amyloid beta-Peptides↗
PubMed1998

Resveratrol as a new type of DNA-cleaving agent.

The first demonstration of DNA cleavage by resveratrol '3,5,4'-trihydroxy-trans-stilbene' is presented. Resveratrol mediated relaxation of pBR322 at micromolar concentrations in the presence of Cu2+. Evidence is provided that resveratrol is capable of binding to DNA, and that the Cu(2+)-dependent DNA damage is more likely caused by a copper-peroxide complex rather than by a freely diffusible oxygen species.

Antineoplastic Agents, Phytogenic↗
PubMed2001

Protective effects of resveratrol on hydrogen peroxide-induced apoptosis in rat pheochromocytoma (PC12) cells.

Oxidative stress has been considered as a major cause of cellular injuries in a variety of clinical abnormalities. One of the plausible ways to prevent the reactive oxygen species (ROS)-mediated cellular injury is dietary or pharmaceutical augmentation of endogenous antioxidant defense capacity. Resveratrol (3,5,4'-trihydroxy-trans-stilbene), one of the major antioxidative constituents found in the skin of grapes, has been considered to be responsible in part for the protective effects of red wine consumption against coronary heart disease ('French Pardox'). In this study, we have investigated the effects of resveratrol on hydrogen peroxide-induced oxidative stress and apoptotic death in cultured rat pheochromocytoma (PC12) cells. PC12 cells treated with hydrogen peroxide underwent apoptotic death as determined by characteristic morphological features, internucleosomal DNA fragmentation and positive in situ end-labeling by terminal transferase (TUNEL staining). Resveratrol pretreatment attenuated hydrogen peroxide-induced cytotoxicity, DNA fragmentation, and intracellular accumulation of ROS. Hydrogen peroxide transiently induced activation of NF-kappaB in PC12 cells, which was mitigated by resveratrol pretreatment. These results suggest that resveratrol has the potential to prevent oxidative stress-induced cell death.

Animals↗
PubMed1999

Molecular mechanisms of chemopreventive effects of selected dietary and medicinal phenolic substances.

Recently, considerable attention has been focused on identifying naturally occurring chemopreventive substances capable of inhibiting, retarding, or reversing the multi-stage carcinogenesis. A wide array of phenolic substances, particularly those present in dietary and medicinal plants, have been reported to possess substantial anticarcinogenic and antimutagenic activities. The majority of these naturally occurring phenolics retain antioxidative and anti-inflammatory properties which appear to contribute to their chemopreventive or chemoprotective activity. Capsaicin (trans-8-methyl-N-vanillyl-6-nonenamide), a pungent ingredient of hot chili pepper, protects against experimentally-induced mutagenesis and tumorigenesis. It also induces apoptosis in various immortalized or malignant cell lines. Plants of ginger family (Zingiberaceae) have been frequently and widely used as spices and also, in traditional oriental medicine. Curcumin, a yellow ingredient from turmeric (Curcuma longa L., Zingiberaceae), has been extensively investigated for its cancer chemopreventive potential. Yakuchinone A [1-(4'-hydroxy-3'-methoxyphenyl)-7-phenyl-3-heptanone] and yakuchinone B [1-(4'-hydroxy-3'-methoxyphenyl)-7-phenylhept-1-en-3-one] present in Alpinia oxyphylla Miquel (Zingiberaceae) have inhibitory effects on phorbol ester-induced inflammation and skin carcinogenesis in mice, and oxidative stress in vitro. These diarylheptanoids suppress phorbol ester-induced activation of ornithine decarboxylase and production of tumor necrosis factor-alpha or interleukin-1alpha and their mRNA expression. They also nullified the phorbol ester-stimulated induction of activator protein 1 (AP-1) in cultured human promyelocytic leukemia (HL-60) cells. In addition, both yakuchinone A and B induced apoptotic death in HL-60 cells. Ginger (Zingiber officinale Roscoe, Zingiberaceae) contains such pungent ingredients as [6]-gingerol and [6]-paradol, which also have anti-tumor promotional and antiproliferative effects. Resveratrol (3, 5,4'-trihydroxy-trans-stilbene), a phytoalexin found in grapes and other dietary and medicinal plants, and (-)-epigallocatechin gallate, a major antioxidative green tea polyphenol, exert striking inhibitory effects on diverse cellular events associated with multi-stage carcinogenesis. In addition, these compounds have ability to suppress proliferation of human cancer cells via induction of apoptosis.

Animals↗
PubMed2003

Metabolic engineering of Saccharomyces cerevisiae for the synthesis of the wine-related antioxidant resveratrol.

The stilbene resveratrol is a stress metabolite produced by Vitis vinifera grapevines during fungal infection, wounding or UV radiation. Resveratrol is synthesised particularly in the skins of grape berries and only trace amounts are present in the fruit flesh. Red wine contains a much higher resveratrol concentration than white wine, due to skin contact during fermentation. Apart from its antifungal characteristics, resveratrol has also been shown to have cancer chemopreventive activity and to reduce the risk of coronary heart disease. It acts as an antioxidant and anti-mutagen and has the ability to induce specific enzymes that metabolise carcinogenic substances. The objective of this pilot study was to investigate the feasibility of developing wine yeasts with the ability to produce resveratrol during fermentation in both red and white wines, thereby increasing the wholesomeness of the product. To achieve this goal, the phenylpropanoid pathway in Saccharomyces cerevisiae would have to be introduced to produce p-coumaroyl-CoA, one of the substrates required for resveratrol synthesis. The other substrate for resveratrol synthase, malonyl-CoA, is already found in yeast and is involved in de novo fatty-acid biosynthesis. We hypothesised that production of p-coumaroyl-CoA and resveratrol can be achieved by co-expressing the coenzyme-A ligase-encoding gene (4CL216) from a hybrid poplar and the grapevine resveratrol synthase gene (vst1) in laboratory strains of S. cerevisiae. This yeast has the ability to metabolise p-coumaric acid, a substance already present in grape must. This compound was therefore added to the synthetic media used for the growth of laboratory cultures. Transformants expressing both the 4CL216 and vst1 genes were obtained and tested for production of resveratrol. Following beta-glucosidase treatment of organic extracts for removal of glucose moieties that are typically bound to resveratrol, the results showed that the yeast transformants had produced the resveratrol beta-glucoside, piceid. This is the first report of the reconstruction of a biochemical pathway in a heterologous host to produce resveratrol.

Acyltransferases↗
PubMed1999

Determination of trans-resveratrol in plasma by HPLC.

trans-Resveratrol (trans-3,5,4'-trihydroxystilbene), a phenolic compound present in grapes, wines, and peanuts, has been reported to have health benefits including anticarcinogenic effects and protection against cardiovascular diseases. Despite its importance, little is known about its bioavailability in both humans and animals. A fundamental step for this evaluation consisted in measuring this stilbene in blood. In the present work, a simple and rapid HPLC method with diode array-UV detection has been developed. Resveratrol contained in plasma was purified by solid-phase extraction using a C18 cartridge. The sample was rinsed with water and methanol-water (25:75 v/v), and trans-resveratrol was finally eluted with methanol. The collected fraction was evaporated under nitrogen and analyzed by HPLC. The method was validated by obtaining a linear correlation, a detection limit of 20 micrograms/L, and a good precision with a coefficient of variation of 2.85%. trans-Resveratrol administered orally to rats was detected in plasma. With this procedure, excellent separation of trans-resveratrol is achieved, thus allowing a rapid analysis of the sample for absorption, distribution, and metabolism studies.

Animals↗
PubMedDate not supplied

A concise synthesis of the 3-O-beta-D- and 4'-O-beta-D-glucuronide conjugates of trans-resveratrol.

trans-Resveratrol ((E)-3,4',5-trihydroxystilbene, 1) is a phytoalexin produced naturally in plants and grape skins as a stress metabolite protecting against fungal attack. Widespread interest in this apparently structurally simple molecule and synthetic stilbene analogues has arisen in recent years due to the discovery of its antioxidant, antiinflammatory, and anti-carcinogenic activities, among others. Although O-conjugation with glucuronic acid in vivo is known to represent a significant metabolic pathway for polyphenolic compounds in general and 1 in particular, preclinical studies have been hampered by the lack of chemically pure, completely characterized reference standards of both regioisomeric 3-O-beta-d- and 4'-O-beta-d-glucuronide conjugates of 1 for adequate identification and quantification of these significant metabolites. The present work describes a concise, convergent synthesis of both 3-O-beta-d- and 4'-O-beta-d-glucuronide conjugates of 1 using a strategy based on a novel Heck coupling of iodoaryl-O-beta-d-glucuronate esters with appropriately substituted styrenes, such that highly pure multimilligram to gram quantities of both the 3-O-beta-d- and 4'-O-beta-d-glucuronide conjugates of 1 can now be conveniently synthesized.

Glucuronides↗
PubMed1992

Protein kinase A dependent membrane protein phosphorylation and chloride conductance in endosomal vesicles from kidney cortex.

Regulation of Cl conductance by protein kinase A may play a role in control of endosomal acidification [Bae, H.-R., & Verkman, A. S. (1990) Nature, 348, 637-639]. To investigate the mechanism of kinase A action, cell-free measurements of Cl transport and membrane protein phosphorylation were carried out in apical endocytic vesicles from rabbit kidney proximal tubule. Cl transport was measured by a stopped-flow quenching assay in endosomes labeled in vivo with the fluorescent Cl indicator 6-methoxy-N-(3-sulfopropyl)quinolinium. Phosphorylation was studied in a purified endosomal preparation by SDS-PAGE and autoradiography of membrane proteins labeled by [gamma-32P]ATP. Endosomes had a permeability (PCl) for conductive Cl transport of 3.1 x 10(-8) cm/s at 23 degrees C which was stilbene inhibitable. PCl was increased by 90 +/- 20% by a 10-min preincubation with the catalytic subunit of kinase A (PKA, 10 units/mL) and MgATP (0.5 mM) with anion selectivity Cl greater than I greater than Br. The increase in PCl was blocked by 100 microM N-[2-(methylamino)ethyl]-5-isoquinolinesulfonamide (H-8) and was reversed by addition of alkaline phosphatase (AP, 40 units/mL) after incubation with PKA and MgATP; the increase in PCl was not blocked by pretreatment with AP.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Species differences in cytochromes P-450 and epoxide hydrolase: comparisons of xenobiotic-induced hepatic microsomal polypeptides in hamsters and rats.

Cytochromes P-450 and epoxide hydrolase in hamsters were studied by using two-dimensional gel electrophoresis of hepatic microsomes from untreated animals and those treated with phenobarbital, 3-methylcholanthrene, beta-naphthoflavone, trans-stilbene oxide, and pregnenolone-16 alpha-carbonitrile. Coelectrophoresis with corresponding microsomes from rats and in situ peptide mapping were used to identify resolved microsomal polypeptides as cytochromes P-450 or epoxide hydrolase. Two forms of hepatic microsomal epoxide hydrolase were shown to exist in hamsters; these evidenced extensive structural homology with the corresponding enzyme in rats and were induced by the same xenobiotics. At least eight inducible polypeptides in microsomes from hamsters were tentatively identified as cytochromes P-450. Two of these were electrophoretically identical and structurally related with previously characterized forms of the enzyme in rats. Homologues of several major cytochromes P-450 induced by pregnenolone-16 alpha-carbonitrile and/or phenobarbital in the rat were apparently not present in the hamster. In most cases, putative forms of inducible cytochrome P-450 in the hamster existed at significant levels in microsomes from untreated animals whereas in rats the levels of most inducible forms of the enzyme were low in control microsomes, being more strictly dependent on xenobiotic pretreatment. In contrast with epoxide hydrolase, the molecular complexity of hepatic cytochrome P-450 seems to be comparable for rats and hamsters, but the structure and control of these hemoproteins appear to have markedly diverged.

Animals↗