4 结果
In a continuation of our search for potential tumor inhibitors from plants, we found that a crude extract from Ocotea leucoxylon showed selective activity typical of inhibitors of the enzyme topoisomerase I in a yeast assay for DNA-damaging agents. Using a bioassay-directed fractionation approach,
Bioassay-guided fractionation of the cytotoxic ethyl acetate fraction of the sequential methanol extract from the leaves and twigs of Dasymaschalon sootepense led to the isolation of a new 7-hydroxy aporphine alkaloid, 6a,7-dehydrodasymachaline (1) along with the five known compounds
Phytochemical investigation of the ethanol extract from the roots of Toddalia asiatica resulted in the isolation of eight new alkaloids, 8-methoxynorchelerythrine (1), 11-demethylrhoifoline B (2), 8-methoxynitidine (3), 8-acetylnorchelerythrine (4), 8,9,10,12-tetramethoxynorchelerythrine (5),
Bioassay-guided fractionation of the cytotoxic ethyl acetate extract from the stems of Dasymaschalon blumei (Annonaceae) led to the isolation of four aristololactam alkaloids, including the hitherto unknown 3,5-dihydroxy-2,4-dimethoxyaristolactam (1), as well as the three known compounds,