Exploration of Pharmacophore in Chrysosplenol C as Activator in Ventricular Myocyte Contraction

摘要

Chrysosplenol C (4',5,6-trihydroxy-3,3',7-tri-methoxyflavone) isolated from Miliusa balansae has unique structural features as a reversible inotropic agent independent of beta-adrenergic signaling and with selective activation of cardiac myosin ATPase. Hence, a series of chrysosplenol analogues were synthesized and explored for identification of pharmacophore that is essential for the increasing contractility in rat ventricular myocytes. Analogue 7-chloro-2-(3-hydroxypheny1)-3-methoxy-4H-chromen-4-one showed highly potent contractility (54.8% at 10 mu M) through activating cardiac myosin ATPase (38.7% at 10 mu M). Our systematic structure activity relationship study revealed that flavonoid nucleus of chrososplenol C appears to be an essential basic skeleton and hydrophobic substituent at position 7 of chromenone such as methoxy or chloro enhances the activity. Additionally, our ATPase study suggested that these chrysosplenol analogues have selectivity toward cardiac myosin activation. Thus, the novel flavonone with 3-/7-hydrophobic substituent and 3'-hydrogen bonding donor function is a novel scaffold for discovery of a new positive inotropic agent.