Phytochemical analysis of Pithecellobium dulce (Roxb.) Benth. unripe aril via LC- MS/MS and evaluation of its antiproliferative activity against human colon carcinoma cells

The present study aimed to identify the bioactive compounds from the Pithecellobium dulce (Roxb.) Benth. unripe aril via LC-MS/MS (liquid chromatography-tandem mass spectrometry) and evaluate its antiproliferative activity against human colon carcinoma cells. Unripe aril powder was extracted with methanol and water (70:30). The LC-MS/MS chromatogram showed the presence of 20 different phytochemical compounds such as justicidin B, 2-hydroxyquinoline, hyoscyamine, kaempferol, cyanidin, hypoxanthine, chicoric acid, roemerine, amentoflavone, and cinnamic acid, etc. An extensive literature survey revealed the reported anticancer properties of these compounds. PD fruit and bark extracts have already reported cinnamic acid, kaempferol, morin, and catechin B. The extract demonstrated dose -dependent antiproliferative effects against HT-29 and HCT-15 cells with IC50 values of 62.5 mu g/ml by MTT assay. Moreover, the extract enhanced the reactive oxygen species level, altered cellular morphology, and induced apoptosis as analyzed by fluorescence microscopy. Our current findings suggest PDU produces significant levels of reactive oxygen species (2.5 fold), which may cause apoptosis by disrupting the balance between the oxidant and antioxidant enzyme systems to alter the redox balance in the cell. Interstingly, PDU at the highest concentration (125 mu g/ml) tested significantly enhances the release of lactate dehydrogenase (LDH, 4-fold) in HT-29 and HCT-15 cells. This result suggests the involvement of necrosis in the cytotoxic effect of PDU. In conclusion, our results suggest that P. dulce unripe aril contains potent anticancer agents that demonstrate significant antiproliferative and apoptotic activity against human colon carcinoma cells. Therefore, the consumption of unripe fruits of P. dulce has important gut and digestive health benefits.