hopeaphenol and epsilon-viniferin

Grapevine co-products, as canes, represent a source of compounds of interest to control vineyard diseases with a sustainable approach. We chose to study an extract that we produced from grapevine trunk and roots. This extract, enriched in complex stilbenes, strongly reduced mycelial growth and spore germination of

Topics: Antifungal Agents; Plant Extracts; Resveratrol; Stilbenes; Vitis

Grapevine canes are rich in resveratrol and its complex derivatives. These compounds have many biological activities and are needed mainly for health purposes. Canes, which are often wasted, can be used to produce these high-value compounds at low cost. We studied sixteen Vitis vinifera L. cultivars among the most widely cultivated ones worldwide. Polyphenols were extracted from their canes and identified by liquid chromatography-nuclear magnetic resonance spectroscopy. We accurately determined the content of E-ε-viniferin, E-resveratrol, E-piceatannol, and vitisin B and, for the first time, that of hopeaphenol and miyabenol C. The canes did not contain these major stilbene compounds in similar proportions, and their abundance and order of abundance varied according to the cultivar. For instance, Pinot noir has very high levels of E-resveratrol and E-ε-viniferin; Gewurztraminer has very high levels of vitisin B, and Carignan and Riesling have very high levels of hopeaphenol. These findings suggest that the right cultivar should be used to obtain the highest yield of a polyphenol of interest.

Topics: Benzofurans; Chromatography, Liquid; Phenols; Plant Stems; Polyphenols; Resveratrol; Species Specificity; Stilbenes; Vitis

Resveratrol, piceatannol, ε-viniferin, r-viniferin, r2-viniferin, and hopeaphenol are naturally occurring polyphenols, associated with potentially beneficial health effects. We developed a rapid liquid chromatography-ultraviolet detection (LC-UV) method, allowing for the simultaneous determination of these six compounds in biological samples in less than 2.5 min with standard LC equipment. Using this method for the assessment of the stability of the six analytes, we demonstrated that all stilbene polyphenols disappear rapidly in Dulbecco's modified Eagle's medium (e.g., half-life of resveratrol of 1 h). In contrast, the tetramer hopeaphenol was stable over the maximum incubation time of 72 h. In incubations with liver microsomes, ε-viniferin was rapidly glucuronidated, although to a lower extent than resveratrol. Hopeaphenol was not glucuronidated at all. Given that glucuronidation is the major metabolic pathway for polyphenols, hopeaphenol might exhibit significantly different pharmacokinetic properties than other polyphenols. When chemical and metabolic stability as well as biological activity of hopeaphenol are taken together, these findings warrant further investigation of this polyphenol.

Topics: Benzofurans; Chromatography, Liquid; Drug Stability; Glucuronides; Humans; Microsomes, Liver; Molecular Structure; Phenols; Polyphenols; Resveratrol; Stilbenes

An activity-guided isolation of bioactive stilbenes has been carried out with the grapevine-shoot extract Vineatrol 30. After hexane precipitation of the polymeric constituents, the stilbene mixture was separated on a preparative scale using low-speed rotary countercurrent chromatography (LSRCCC). The antiproliferative activity of the separated LSRCCC fractions was then screened in the human cancer cell line A-431, and trans-resveratrol, trans-ε-viniferin, r-2-viniferin, hopeaphenol, and miyabenol C were identified as active principles. In addition, a new class of stilbene derivatives, which exhibit a γ-lactam ring structure and exert a weak growth-inhibiting activity in A-431 cells, has been identified.

Topics: Antineoplastic Agents, Phytogenic; Benzofurans; Cell Line, Tumor; Chemical Fractionation; Countercurrent Distribution; Drug Screening Assays, Antitumor; Humans; Molecular Structure; Phenols; Plant Shoots; Resveratrol; Stilbenes; Vitis