We describe a reversed-phase HPLC method that uses gradient elution and diode array detection to quantitate eight biologically active phenolic constitutions of wine: the cis and trans isomers of resveratrol and their glucosides, catechin, epicatechin, quercetin, and rutin. ODS Hypersil served as the stationary phase; the gradient was formed by acetic acid, methanol and water. Each analysis required an equilibration period of ten minutes and a run time of fourty minutes for completion. Satisfactory peak resolution was achieved following direct injection of a 20-muL sample, and validation was accomplished by on-line spectral comparisons with known standards. Excellent linearity was obtained for all constituents, and the detection limits ranged from 30 mug/L (trans-resveratrol) to 1.5 mg/L (catechin). Recoveries approximated 100% range (95.2-105.5%), and the method provided good precision, with coefficients of variation between 1.17 and 3.38%. All of the phenolics measured were reasonably stable in opened wines protected against sunlight for up to 1 week at room temperature or 4 degrees C, but most showed losses of 10-40% when stored for 6 weeks at either temperature.

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We have developed a novel method to measure the concentration of the trihydroxystilbene trans-resveratrol suitable for the analysis of wine and other biological materials. Solid-phase extraction is carried out on a reversed-phase disposable C-18 cartridge with elution of tirans-resveratrol by ethyl acetate. From the first 1 mL of the eluate collected, 1 #iL is injected directly into a gas chromatograph/mass spectrometer coupled through a DB-5 column. The molecular ion at a mass of 228 was quantitated by selective ion monitoring using as standard frans-resveratrol synthesized by a Wittig reaction. The method was linear up to 10 mg/L with a detection limit of 0.05 mg/L, which can be increased 10-fold if required. Recovery of added synthetic trans-resveratrol in wine ranged from 83 to 111% with a mean of 100%. Within-run precision was 5-7%. The method is faster and simpler than those previously published, which use organic-phase extraction, and yields higher values in wine presumably as a consequence of minimal loss during the solid-phase extraction. The trans-resveratrol concentration of wine is stable when protected from light for at least 6 weeks at 4 °C and for at least 1 week at room temperature.Zra«i-Resveratrol (3,5,4'-trihydroxystilbene) has been identified as a constituent of many plant species, including vitis vinifera.M It has potent antifungal properties and appears to be synthesized by vines in response to fungal infection.* 12345 678™9 Biological interest in Zranr-resveratrol was stimulated by reports of its presence in Japanese herbal medications used for the treatment of fungal, inflammatory, and lipid disorders.10 Subsequent experiments with purified Zrons-resveratrol demonstrated many biologically useful functions including modu-