Marginolides A-B, polyether macrolide analogues from veined octopus Amphioctopus marginatus: anti-hypertensive leads attenuate angiotensin-converting enzyme.

Angiotensin-I-converting enzyme (ACE) is considered as a major drug target for the treatment of hypertension as it catalyses the production of vasoconstrictor angiotensin II from angiotensin I. ACE inhibitor agents are an effective therapeutic strategy to control high blood pressure. Unprecedented polyether macrolides, marginolide A and B were isolated from the crude extract of marine octopus, Amphioctopus marginatus via bioassay-directed sequential chromatographic fractionation. Marginolide A displayed considerably greater ACE attenuation potential (IC50 0.58 mM) than that exhibited by marginolide B (IC50 0.72 mM). Higher antioxidant properties of marginolide A against the oxidant species (IC50 ∼ 1 mM) also supported its potential ACE inhibitory activity. Higher polar characteristics along with acceptable hydrophobic-hydrophilic equilibrium (partition coefficient of octanol-water, log Pow 2-4) revealed the potential anti-hypertensive activities of marginolides. This study recognized the anti-hypertensive properties of marginolides as promising pharmaceutical leads.