A Comparative Study of the Anti-Platelet Effects of cis- and trans-Resveratrol

the stimulation of nitric oxide generation (Gresele et al., 2008), and the modulation of signaling molecules such as protein kinase C (Yang et al., 2008b), phospholipase C (Yang et al., 2008a), p38 MAPK (Shen et al., 2007). Resveratrol exists as either the trans-isomer [(E)-resveratrol, 5-{(E)-2-(4-hydroxyphenyl)ethenyl}benzene-1,3-diol; CAS Number 501-36-0] or cis-isomer [(Z)-resveratrol, 5-{(Z)-2-(4-hydroxyphenyl)ethenyl}benzene-1,3-diol; CAS Number 61434-67-1] (Orallo, 2006) (Fig. 1). The term resveratrol has, however, generally referred to only the trans-isomer and little attention has been paid to cis-resveratrol. As a necessary consequence, most studies were done with trans-resveratrol or with an undefi ned mixture of both isomers, and little is known regarding the biological activities of cis-resveratrol (Orallo, 2006). This has been the case with studies described above reporting the anti-platelet effects of resveratrol. This may have been due to the absence, until recently, of commercially available cisresverarol (Leiro et al., 2004; Orallo, 2006). Now, however, a few chemical companies have started to produce cis-isomer. There are only a limited number of reports that have examined the biological effects of cisversus trans-resveratrol. For instance, cis-resveratrol exhibited slightly weaker effects in Original Article Biomol Ther 19(2), 201-205 (2011)