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

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 µM. The antioxidant property of the compound was compared with α-tocopherole and vitamin C having IC₅₀ values 96 ± 0.46 and 90 ± 0.56 µM, respectively. In case of antiglycation assay, the compound exhibited moderate activity (IC₅₀ = 355 ± 7.56 µM) similar to standard compound, rutin (IC₅₀ = 294 ± 0.56 µM). 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. [ABSTRACT FROM AUTHOR]