In vitro cytotoxic activity of indole alkaloids from Croton echioides
The genus Croton (Euphorbiaceae) is a rich source of secondary metabolites such as alkaloids, flavonoids, and terpenoids, which have prominent pharmacological properties [1,2]. Croton echioides, a Brazilian medicinal plant, is used in folk medicine because of its aphrodisiac reputation and tonic property. In this study, size exclusion chromatography and preparative MPLC were used to isolate four indole alkaloids from the ethanol stem-bark extract. Their structures were characterized as: N-trans-coumaroyl-tryptamine (1), N-trans-coumaroyl-5-hydroxytryptamine (2), N-trans-4-methoxycinnamoyl-5-hydroxytryptamine (3), and N-trans-feruloyl-5-hydroxytryptamine (4) by 1D and 2D NMR analysis, EI-MS, and chemical evidence. Each compound was evaluated against HCT-116 colon carcinoma cells , and their CC50 (µg/mL) were 47.5 (1), 72.7 (2), 29.4 (3), and 53.3 (4). These results indicate that the substitution of the hydroxyl group at R3 by a methoxyl group in 3 increased the cytotoxic activity. The substitution of the group at R1 had no effect.
Acknowledgements: CAPES, CNPq, INCT_if.
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2. Payo, H. et al. (2001) Rev. Cubana Farm. 35: 203–206.
3. Skehan, P et al. (1990)J. Natl. Cancer Inst. 82: 1107–1112.