Purification and antioxidant capacity analysis of anthocyanin glucoside cinnamic ester isomers from Solanum nigrum fruits.

In a recent study, anthocyanins, which have a strong free radical-scavenging activity, were examined for their potential to effectively prevent cancer. However, clinical trials are limited by the purity of the anthocyanin. Multiple methods are used to extract and purify anthocyanins. Based on previous work on Solanum nigrum, which is a widely distributed plant, in this study, DM130 macroporous resin, Sephadex LH20, and a C18 column were used to separate cis-trans anthocyanin isomers. These anthocyanins constitute the majority of total S. nigrum anthocyanins. The results showed that this "DM130-LH20-C18 system" can be used to obtain a cinnamic acid-derived cis-trans anthocyanin, petunidin-3-(p-coumaroyl)-rutinoside-5-glucoside, with a purity of 98.5%, for effective quantitation. In order to determine the antioxidant ability of the petunidin-3-(p-coumaroyl)-rutinoside-5-glucoside cis-trans isomers, three ordinary methods were adopted. The maximum antioxidant ability of the cis-trans anthocyanin was dozens of times higher than that of vitamin C.