Resveratrol extract is a substance also known as phytoalexin, and is similar to an antibiotic. When a plant has been damaged by bacteria or fungi, it produces resveratrol. Resveratrol was found in the white hellebore, a plant member of the lily family. It was also found in the Japanese knotweed. A resveratrol extract is in the skin and seed of grapes, and has been noted as the reason for the benefit of drinking wine for people with heart disease.
Laboratories have been able to duplicate resveratrol extract by synthesizing it chemically. Once the plant has been tested so that it does not contain any contaminates by chemicals or other materials, it is placed within large metal containers called extractors. The resveratrol extract is separated from the fibers of the plant using ethanol or methanol. Then there is further processing by exposing the extract to high pressure. Now the purified extract is vacuum-dried to remove the alcohol.