Identification and Antiproliferative Activity Evaluation of a Series of Triterpenoids Isolated from Flueggea virosa (Roxb. ex Willd.)

Abstract

Problem statement: Medicinal plants derived anticancer were now being subjects of many research groups especially, the secondary metabolite triterpenoids trees which had enormous potential to inspire and influence modern antiproliferative research. The study aimed to investigate the chemical constitution and their potential use as antiproliferative activity of purified compounds derived from F. virosa. Approach: The F. virosa was selected and percolated with hexane, ethyl acetate, acetone and methanol. The extracts were purified and elucidated chemical structures. Furthermore, the isolated compounds were tested for biological activity. The bioassays were performed on two cancer cell lines, adriamycin-sensitive erythroleukemia cells (K562) and adriamycin-resistant erythroleukemia cells (K562/Adr) which overexpressed P-glycoprotein (MDR1/ABCB1). Results: Friedelin (1), epifriedelanol (3), stigmasterol (4) and betulinic acid (5) were isolated from the leaves and twigs of F. virosa. The molecular structures of these compounds were determined using several spectroscopic methods. The compounds i.e., 1, a chemically modified compound 1 heptanolide (2), 3 and 4 showed a limited cytotoxic activity towards human cancer cell lines mainly due to a low aqueous solubility which prevented their use in cell viability assays. Interestingly, compound 5 exhibited a high cytotoxicity characterized by an effective concentration value (IC₅₀) equal to 9.7±2.1 µg.mL^-1 (21.2±4.6 µM) and 7.1±0.7 µg.mL^-1 (15.5±1.5 µM) for K562 and K562/Adr, respectively. Moreover, the antiproliferative activity of compound 5 was independent of the multidrug resistance phenotype exhibited by the K562/Adr cell line suggesting that compound 5 was not the effluxes out of the K562/Adr cells by MDR1 (ABCB1). Conclusion: The results clearly showed that the betulinic acid of the four isolated compounds from F. virosa could be considered as high potential source of cytotoxic activity.