Isolation, Quantitative Phytochemical Profiling, and NMR Spectroscopic Characterization of Lupeol Acetate from the Stem Bark of Cissus populnea

Medicinal plants are one of the major plant sources for bioactive compounds which has a great therapeutic value. Cissus populnea is a medicinal plant, traditionally used in West Africa, but there is little information on phytochemicals and structural characterization of its bioactive metabolites. The aim of this study was to evaluate the quantitative phytochemical composition of stem bark of Cissus populnea in different solvents and isolate and characterize lupeol acetate by Nuclear Magnetic Resonance (NMR) spectroscopy. The powdered stem bark was sequentially extracted using hexane, ethyl acetate and methanol. The quantitative phytochemical analysis for phenolics, tannins, flavonoids, steroids, glycosides and terpenoids were performed using the standard spectrophotometric method. The bioactive compound was isolated by silica gel column chromatography and structural elucidation was accomplished by ¹H NMR, ¹³C NMR, HSQC and HMBC spectroscopic methods. The results of the experiments were presented as mean ± standard deviation of three times determination and analyzed by one-way ANOVA at P<0.05. The methanol extract contained the highest amount of phenolics (0.513 ± 0.003), tannins (0.664 ± 0.003), flavonoids (0.822 ± 0.002) and terpenoids (0.165 ± 0.002); glycosides and steroids were the highest in the hexane and ethyl acetate extracts, respectively. The isolated compound was identified as lupeol acetate based on its diagnostic signals, which showed the presence of a lupane-type pentacyclic triterpenoid skeleton with an acetyl group.