ABSTRACT
Stilbenes have been found in a number of plant families (Ingham, 1976, 1982; Ingham and Harborne, 1976). Their antifungal nature has been implicated in preventing wood decay (Hart and Shrimpton, 1979; Hart, 1981) and in disease resistance of plants against different pathogens (Ward et al., 1975; Ingham, 1976; Hart, 1981; Aguamah et al., 1981). Biosynthetically, stilbenes are derived from the shikimic-polymalonic acid pathway. Stilbene synthase, which is the key enzyme in the biosynthesis of stilbenes in groundnuts (Arachis hypogaea) and also in Vitis spp. (Fritzemeier and Kindl, 1981; Melchior and Kindl, 1991), converts one molecule of p-coumaroyl-CoA and three molecules of malonyl-CoA into 4,3’,5’-trihydroxystilbene, commonly known as trans-resveratrol (Ingham, 1976; Rupprich and Kindl, 1978). In UV-irradiated grapevine leaves, phenylalanine was a good but tyrosine a poor precursor (Langcake and Pryce, 1977b), indicating that the 4’-hydroxyl is probably introduced at the cinnamic acid stage. trans-Resveratrol (hereafter resveratrol) appears to be the most widely distributed stilbene in several plant families.
