Antitumor Activity of Liposomal Naphthoquinone Esters Isolated from Thai Medicinal Plant:Rhinacanthus nasutus Kurz

摘要

We previously observed that rhinacanthins-C,-N and -Q,three main naphthoquinone esters isolated from the roots of Thai medicinal plant;Rhinacanthus nasutus Kurz.(Acanthaceae) induced apoptosis of human cervical carcinoma HeLaS3 cells.Since these rhinacanthins showed limited solubility in aqueous medium,we attempted to entrap them into liposomal membrane:Liposomalization enabled injection of the drugs and the drugs were expected to transfer to lipoproteins in the bloodstream.Liposomal formulations of rhinacanthins-C,-N and -Q showed strong antiproliferative activity against HeLaS3 cells with the IC_(50) values of 32,17,70 muM;19,17,52 muM and 2.7,2.0 and 5.0 muM for the exposure time of 24,48,and 72 h,respectively.These liposomes suppressed the tumor growth in Meth-A sarcoma-bearing BALB/c mice at the dose of 5.0 mg/kg/d for 10 d.Among rhinacanthins,liposomal rhinacanthin-N significantly suppressed solid tumor growth.Based on these results,our findings demonstrated that rhinacanthin-N suppressed tumor growth in vivo,and suggested that liposomes are useful for preparing injectable formulation of hydrophobic drugs.