Alkaline phosphatase activity-guided isolation of active compounds and new dammarane-typetriterpenes from Cissus quadrangularis hexane extract

Abstract

Ethnopharmacological relevance: The stem of Cissus quadrangularis L. (CQ)is used in traditional medicine to treat bone fractures and swelling. Anti-osteoporotic activity of CQ hexane extract as been reported, but the active compounds in this extract remain unknown. Thus,we aimed to identify the active compounds in CQ hexane extract using bioassay-guided isolation. Materials and methods: The CQ hexane extract was fractionated sequentially with benzene,dichlor-omethane, ethyl acetate,and methanol. The examination of CQ extract and its fractions was guided by bioassays for alkaline phosphatase(ALP)activity during the differentiation of MC3T3-E1osteoblastic cells. The cells were treated with or without the CQ extract and its fractions for a period of time,and then the stimulatory effect of the alkaline phosphatase enzyme,a bone differentiation marker, was investigated. The compounds obtained were structurally elucidated using spectroscopic techniques and reevaluated for activity during bone differentiation. Results: A total of 29 compounds were isolated, viz., triterpenes, fatty acid methylesters, glycerolipids, steroids, phytols, and cerebrosides. Four new dammarane-typetriterpenes were isolated for the first time from nature, and this report is the first to identify this group of compounds from the Vitaceae family. Seven compounds, viz., glycerolipids and squalene, stimulated ALP activity at a dose of 10 μg/mL. Moreover,the synergistic effect of these compounds on bone formation was demonstrated. Conclusion: This report describes, for the first time,the isolation of active compounds from CQ hexane extract; these active compounds will be useful for the quality control of extracts from this plant used to treat osteoporosis.