Radical scavenging activity of black currant (Ribes nigrum L.) extract and its inhibitory effect on gastric cancer cell proliferation via induction of apoptosis

A black currant extract (BCE) was prepared and its antiproliferative activity against gastric cancer SGC-7901 cells was investigated. Strong 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS) radical scavenging activities and a high reducing power were confirmed with BCE. BCE inhibited the proliferation of SGC-7901 cells in a dose- and time-dependent manner, and the IC ₅₀ were 12.7, 10.2 and 9.0mg/mL for 12, 24 and 48h, respectively. Morphologic observations with inverted and fluorescence microscopes yielded vivid evidence of cell shrinkage, formation of cytoplasmic filaments, condensation of nuclear chromatin, and cell apoptosis in the presence of BCE. Flow cytometric analysis also showed that BCE treatment at concentrations of 10-20mg/mL resulted in marked reductions of viable cells. The high concentration of phenolic compounds present in the BCE (12.2mg/mL), including six prominent anthocyanins identified by HPLC-ESI-MS ², appeared to be responsible for BCE's antiradical activity and anticancer effects. These findings of inhibition of SGC-7901 cells and induction of apoptosis suggest that black currant may contribute to the reduction in gastric cancer risk.