Abstract
Background:
The anticancer effects of Phyllanthus amarus extract on various cancer cells
have been investigated, however, the effects of its major constituents on HCT116 human colorectal
cancer cells have not been reported.
Objective:
In the present study, we investigated the cytotoxic effect of 80% ethanol extract of P. amarus
and its marker constituents (phyllanthin, hypophyllanthin, gallic acid, niranthin, greraniin, phyltetralin,
isolintetralin, corilagin and ellagic acid) on HCT116 and their underlying mechanisms of action.
Methods:
Their antiproliferative and apoptotic effects on HCT 116 were performed using MTT assay
and flow cytometric analysis, respectively, while caspases 3/7, 8 and 9 activities were examined using
the colorimetric method. The expression of cleaved poly ADP ribose polymerase enzyme (PARP) and
cytochrome c proteins was investigated by the immune-blot technique.
Results and Discussion:
HPLC and LC-MS/MS analyses demonstrated that the extract contained
mainly lignans and polyphenols. The plant samples markedly suppressed the growth and expansion of
HCT116 cells in a concentration- and time-dependent manner with no toxicity against normal human
fibroblast CCD18 Co. P. amarus extract, phyllanthin and gallic acid induced mode of cell death primarily
through apoptosis as confirmed by the exteriorization of phosphatidylserine. Caspases 3/7, 8,
and 9 activities increased in a concentration-dependent manner following 24h treatment. The expressions
of cleaved PARP (Asp 214) and cytochrome c were markedly upregulated.
Conclusion:
P. amarus extract, phyllanthin and gallic acid exhibited an apoptotic effect on HCT116
cells through the caspases-dependent pathway.