Chemical sunscreens are widely used in topical formulations designed to protect the skin from damage caused by the sun, but their biological effects on the cellular membranes are not yet well known. In the present paper we study the in vivo effect on adenylate cyclase activity of benzophenonic and cinnamic derivatives containing quaternary ammonium group and possessing good characteristic of sunscreens. The enzymatic activity was evaluated in membranes of L929 cells previously treated with the surnamed compounds. The activity was assayed in basal conditions or in presence of stimulators (forskolin, NaF, AlCl3 and GTP). All the sunscreens inhibit the adenylate cyclase activity; these results suggest that these compounds modulate the enzymatic activity
