Castavinol C3 is a castavinol, a natural phenolic compound found in red wines.
See also phenolic compounds found in wine
References
External links 1996 : Les molécules des futurs millésimes Bordelais ? C. Castagnino, C. Chèze and J. Vercauteren, Bull. Soc. Pharm. Bordeaux, 1997, 136, pp. 19-36 (French)