Antimutagenic activity of a secoisopimarane diterpenoid from Salvia cinnabarina M. Martens et Galeotti in the bacterial reverse mutation assay

The effects of 3,4-secoisopimar-4(18),7,15-trien-3-oic acid, a diterpenoid isolated from Salvia cinnabarina, were evaluated in the Ames test on Salmonella typhimurium TA98 and TA100 and on Escherichia coli WP2uvrA, in presence and in absence of the metabolic activation system.The secoisopimarane diterpenoid not only showed to be devoid of mutagenic activity, but significantly inhibited the effect of some known mutagens, in all strains tested. The reduction of the number of chemically-induced revertant colonies reached the value of 92.2% against 2-aminoanthracene, 59.6% against 2-nitrofluorene, 50.9% against sodium azide and 39.9% against methyl methane sulfonate.It is hypothesized that the secoisopimarane diterpenoid acts by aspecific mechanisms, by alterating the cell permeability thus blocking the mutagen adsorption across the bacterial membrane, or by chemical or enzymatic inhibition of the mutagens.