Effects of aqueous extracts of six marine microalgae on smooth muscle contraction in rat duodenum and vas deferens.

We report the effects of aqueous extracts of six marine microalgae on responses to various contractile agents in isolated rat duodenum (acetylcholine, calcium chloride, barium chloride) and vas deferens (noradrenaline). Our results suggest that only extracts of Phaeodactylum tricornutum, Skeletonema costatum, and Chlorella stigmatophora may have pharmacological potential. Extracts of these three species had spasmolytic effects on responses to the three contractile agents in duodenum. In vas deferens, P. tricornutum and C. stigmatophora inhibited the contractions induced by noradrenaline, whilst S. costatum showed a non-dose-dependent potentiation. With the aim of elucidating their mechanisms of action, we are attempting to isolate the active principles present in these extracts.