Resveratrol (trans-3,5,4'-trihydroxystilbene) is a phytoalexin produced by grapevines in response to fungal infection, particularly to Botrytis cinerea. It has been shown that it possess various biological effects such as prevention of cardiovascular diseases and anti-inflammatory and anticancerogenic properties. Red wines are a primary source of resveratrol. Although a number of investigations have focused on the determination of resveratrol in wines of different countries, there is no similar study about the wines produced in Serbia. As authors are aware, the only study concerning resveratrol content in wine in the Balkan region was conducted in Greece. In this study, the trans- and cis-resveratrol content in samples obtained from 18 commercial Serbian wines (10 red, 7 white, and 1 rose) were analyzed. Analyses were performed after solid-phase extraction by high-performance liquid chromatography with a diode array detection system using an RP-C(18) column with gradient elution [solvent A: acetonitrile-acetic acid-water (20:2:78 v/v), solvent B: acetonitrile-acetic acid-water (90:2:8 v/v)]. Detection of trans- and cis-resveratrol was performed on 306 and 286 nm, respectively. It was clearly established that there was a presence of trans-resveratrol isomers in all analyzed wines (0.11-1.69 mg/L) except in one white wine. Cis-resveratrol was present in 12 from 18 samples in different amounts (0.12-1.49 mg/L).

Resveratrol, which occurs in two isomeric forms, trans and cis, is a phytoalexin with numerous pharmacological activities, such as anti-cancer, antiviral, neuroprotective and anti-aging. Red wine is the main source of the compound and an easy way of including resveratrol in the human diet. In this study, the most popular commercial Serbian wines (red, white and rosé-type) were analyzed for their content of trans-and cis-resveratrol. The analysis was performed by HPLC with a UV detector. Prior to the injection, phenolic compounds were extracted onto a LiChrolut RP18 bonded silica cartridge. The concentration of trans-resveratrol ranged from 0.11 to 1.69 mg L -1 and cis-resveratrol from 0.12 to 1.49 mg L -1 .