Isolation and identification of antioxidant constituents from the flowers of Salvia miltiorrhiza .

A new salvianolic acid derivative, (7' E )-(7 S , 8 S )-salvianolic acid V ( 1 ), together with four previously described compounds ( 2 - 5 ) were obtained from the n -butanol fraction of Salvia miltiorrhiza flowers. Their structures were established by a series of spectroscopic methods, and the absolute configuration of 1 was determined by electronic circular dichroism (ECD) calculation. Salvianolic acids ( 1 ) and phenolic acids ( 2 - 4 ) showed stronger DPPH free radical scavenging abilities and certain protective effects against H 2 O 2 -induced human skin fibroblast (HSF) cells oxidative damage, in which compound 1 (IC 50 7.12  μ M) possessed more noticeable free radical scavenging activity than the positive control vitamin C (IC 50 14.98  μ M).