Inhibitory Effect of Abietic Acid against (Na+ + K+)- and (H + K)-ATPases

Abietic acid, a tricyclic diterpenoidal resin acid, inhibited both (Na+ + K+)- and (H+ + K+)-ATPases, typical membrane-bound enzymes, at a concentration as low as 25 μg/ml. Abietic acid also inhibited gastric acid secretion caused by (H+ + K+)-ATPase. Non-specific inhibition by abietic acid against ATPases suggests that the acid, as well as other biologically active terpenoids, would primarily induce disorganization of the cell membrane constitution.