Inconclusive. I assume you mean "resveratrol" which is an anti-oxidant component of the skin of red grapes. It has been thought to have anti-cancer, anti-inflammatory, "anti-aging, " and blood sugar lowering properties. It seems that most studies are in their infancy and most have used animal models. As far as i know, there is not enough evidence or information to recommend any sort of supplementation with it.
If you believe... Resvinatrol is a combination of resveratrol(the compound that is found to be in wine/grapes; which has been reported to be a panacea for just about everything) and other "antioxidants". Although i might believe there is some merit to the resveratrol; further studies need to be done by the powers that be to determine if that is indeed the case. I would say this..."let the buyer beware".