Chemical Constituents of the Heartwoods of Mansonia gagei and their Biological Activity

Abstract

The dried and ground heartwoods of Mansonia gagei Drumm were successively extracted with hexane, dichloromethane and methanol, respectively. The preliminary bioassay tests indicated that the hexane and dichloromethane crude extracts were biologically active. The separation of both extracts by means of chromatography led to the isolation of ten substances. By means of physical properties, chemical reactions and spectroscopic data, the structures of nine substances were elucidated. They were found to be a mixture of long chain aliphatic ester, 3,8-dimethyl-5-isopropyl-6-methoxy coumarin, 2,3-dihydro-3,6,9-tri-methyl naphtho[1,8-bc]pyran-7-oxa-8-oe, 3,8dimethyl-5-isopropyl-1,2-naphtho-quinone (mansonone C), 3,8-dimethyl-5-isopropyl-6-hydroxy coumarin, a mixture of long chain aliphatic ketones, a mixture of β-sitosterol and stigmasterol, 3,8-dimethyl-5-isopropyl-6-hydroxy-1,2-naphthalenedione (mansonone G), 2,3-dihydro-3,6,9-trimethyl-4-hydroxy-naphtho[1,8-be]pyran-7,8dione (mansonone H.) Except for mansonones C, G and H, the other isolated substances have not been reported to be constituents of plants in Mansonia genus. Moreover, three isolated coumarins were found to be new naturally occurring compounds. Mansonones C and G exhibited cytotoxicity activity against brine shrimp (Artemia salina Linnaeus) with LC50 values of 8.20 and 8.29 at 12 hours, respectively. In addition, 3,8-dimethyl-5-isopropyl-6-methoxy coumarin displayed promising activity as a cytotoxic agent against Hepatocellular carcinoma (Bel-7402) cell line.