Two 1,3-diarylpropanes, 1-(4'-hydroxy-2'-methoxyphenyl)-3-(3"-methoxy-4" -hydroxyphenyl)-propane and 1-(2'-hydroxy-4',6'-dimethoxyphenyl)-3-(3"-methoxy-4" -hydroxyphenyl)-propane, seven flavanones, naringenin, naringenin-4',7-dimethyl-ether, sakuranetin, isosakuranetin, liquiritigenin-4',7-dimethyl-ether, liquiritigenin-7-methyl-ether and liquiritigenin-4'-methyl-ether, two chalcones, isoliquiritigenin-4-methyl-ether and isoliquiritigenin-4'-methyl-ether, one flavan, 7,4'-dihydroxy-3'-methoxyflavan, nine triterpenes, arjunic acid, arjunetin, arjungenin, arjunglucoside I, arjunolic acid, arjunglucoside II, 23-galloylarjunglucoside II (isolated as its mono-, di- and tri-O-methyl derivatives after methylation with diazomethane), betulinic acid and ursolic acid acetate, along with gallic acid and sitosterol were isolated from the heartwood and trunk bark of of Terminalia fagifolia. The flavanones and chalcones obtained in the present work are new in the Combretaceae and this is the first report of the occurrence of 1,3-diarylpropanes in this family. The isolated compounds were evaluated for their in vitro cytotoxic activity against two human cancer cell lines (Hep2 larynx carcinoma and H292 lung mucoepidermoid carcinoma) and antioxidant properties. Isoliquiritigenin-4-methyl-ether, isoliquiritigenin-4'-methyl-ether, 1-(2'-hydroxy-4',6'-dimethoxyphenyl)-3-(3"-methoxy -4"-hydroxyphenyl)-propane and the di- and tri-O-methyl derivatives of 23-galloylarjunglucoside II were the most active in the cytotoxic assay.
Terminalia fagifolia; Combretaceae; diarylpropanes; cytotoxic activity; antioxidant activity
