In vivo inhibitory effects of arjunolic acid derivatives on two‐stage carcinogenesis in mouse skin

Abstract

AbstractIn a previous study, arjunolic acid (1) isolated from Cochlospermum tinctorium and its hemisynthetic derivatives 2, 3 and 4 were shown to exhibit in vitro inhibitory effects on Epstein—Barr virus (EBV) activation. Compounds 3 and 4, which showed the strongest inhibitory activities, were further prepared from arjunolic acid isolated from Mitragyna ciliata; they were tested in vivo on a two‐stage carcinogenesis assay in mouse skin, using dimethyl‐benz[a]anthracene (DMBA) as initiator and 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA) as promoter. The activities were evaluated by both rate (%) of papilloma‐bearing mice and average number of papillomas per mouse and compared with the control. In the group of mice treated with 3 and 4, the occurrence of papillomas was delayed, compared with the results of the control; with derivative 4, papillomas occurred in 100% animals only at week 15. These results suggest that arjunolic acid derivatives could be valuable compounds as antitumour‐promoters.