Ethnopharmacological relevance: Ficus hispida L.f. (Moraceae) has been used as alternative for traditional medicine in the treatment of various ailments including cancer-cure. The aim of this study was to evaluate the cancer chemopreventive and anticancer activities of crude extracts of F. hispida, with the objective to screen the inhibition of Epstein-Barr virus early antigen, and cytotoxic active components, and provide foundation for potential applications of this promising medical plant.
Materials and methods: Compounds were isolated from the MeOH extract of F. hispida fruits, and their structure elucidation was performed on the basis of extensive spectroscopic analysis. The isolated compounds were evaluated for their inhibitory activities against the Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol 13-acetate (TPA) in Raji cells, and cytotoxic activities against human cancer cell lines (HL60, A549, SKBR3, KB, Hela, HT29, and HepG2) and a normal cell (LO2) using MTT method. For the compound with potent cytotoxic activity, its apoptosis inducing activity was evaluated by the observation of ROS generation level expression, and membrane phospholipid exposure and DNA fragmentation in flow cytometry. The mechanisms of the apoptosis induction were analyzed by Western blotting.
Results: Nineteen compounds, 1-19, including two new isoflavones, 3'-formyl-5,7-dihydroxy-4'-methoxyisoflavone (2) and 5,7-dihydroxy-4'-methoxy-3'- (3-methyl-2-hydroxybuten-3-yl)isoflavone (3), were isolated from the MeOH extract of F. hispida fruits. Five compounds, isowigtheone hydrate (1), 2, 3, 9, and 19, showed potent inhibitory effects on EBV-EA induction with IC50 values in the range of 271-340 molar ratio 32 pmol-1 TPA. In addition, five phenolic compounds, 1-3, 10, and 13, exhibited cytotoxic activity against two or more cell lines (IC50 2.5-95.8μM), as well as compounds 1 and 3 were also displayed high selectivity for LO2/HepG2 (SI 23.5 and 11.8, respectively), while the compound 1-induced ROS generation leads to activated caspases-3, -8, and -9 apoptotic process in HL60 cells.
Conclusion: This study has established that the MeOH extract of F. hispida fruits contains isoflavones, coumarins, caffeoylquinic acids, along with other compounds including phenolics and steroid glucoside as active principles, and has demonstrated that the chemical constituents of F. hispida may be valuable as potential chemopreventive and anticancer agents.
Keywords: Anticancer activity; Cancer chemopreventive activity; Epstein–Barr virus early antigen; Ficus hispida L.f.; Phenolic compounds.
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