Isolation of a new bioactive cinnamic acid derivative from the whole plant of Viola betonicifolia

摘要

A new cinnamic acid derivative was isolated from the whole plant of Viola betonicifolia as off white needle. On the basis of various modern spectroscopic techniques including HREI-MS and 1D and 2D NMR, its structure was elucidated as 2,4-dihydroxy, 5-methoxy-cinnamic acid. It showed marked inhibition against DPPH (diphenyl-2-picryl hydrazyl) free radicals with IC50 = 124(+-)5.76 uM. The antioxidant property of the compound was compared with a-tocopherole and vitamin C having IC50 values 96(+-)0.46 and 90(+-)0.56 uM, respectively. In case of antiglycation assay, the compound exhibited moderate activity (IC50 = 355 (+-)7.56 uM) similar to standard compound, rutin (IC50 = 294(+-)0.56 uM). However, it was non-toxic to PC-3 cell line. It is concluded that 2,4-dihydroxy, 5-methoxy-cinnamic acid has antiglycation potential which was further augmented by its antioxidant activity and thus offered an ideal natural therapeutic option for the effective management of diabetes.