Resveratrol is a phytoalexin produced naturally by several plants when under attack by pathogens such as bacteria or fungi. Resveratrol has also been produced by chemical synthesis and is sold as a nutritional supplement derived primarily from Japanese knotweed.

Anti-cancer, anti-inflammatory, blood-sugar-lowering and other beneficial cardiovascular effects of resveratrol have been reported. Resveratrol was originally isolated by Takaoka from the roots of white hellebore in 1940.

In grapes, resveratrol is found primarily in the skin,and ” in muscadine grapes ” also in the seeds. The amount found in grape skins also varies with the grape cultivar, its geographic origin, and exposure to fungal infection. The amount of fermentation time a wine spends in contact with grape skins is an important determinant of its resveratrol content.

Resveratrol (3,5,4′-trihydroxystilbene) is a polyphenolic phytoalexin. It is a stilbenoid, a derivate of stilbene, and is produced in plants with the help of the enzyme stilbene synthase.

The mechanisms of resveratrol’s apparent effects on life extension are not fully understood, but they appear to mimic several of the biochemical effects of calorie restriction. The trans-resveratrol concentration in forty Tuscan wines ranged from 0.3 to 2.1 mg/L in the 32 red wines tested and had a maximum of 0.1 mg/L in the 8 white wines in the test.

Both the cis- and trans-isomers of resveratrol were detected in all tested samples. cis-Resveratrol levels were comparable to those of the trans-isomer. They ranged from 0.5 mg/L to 1.9 mg/L in red wines and had a maximum of 0.2 mg/L in white wines. A new report indicates that resveratrol activates Sirtuin 1 (SIRT1) and PGC-1 and improves functioning of the mitochondria. Another research calls into question the theory connecting resveratrol, SIRT1, and calorie restriction.