Quantitative analysis of triterpene lupeol and anti-inflammatory potential of the extracts of traditional pain-relieving medicinal plants Derris scandens, Albizia procera, and Diospyros rhodocalyx

have traditionally been used as herbal remedies for pain relief in Thailand. The ethanolic extracts of these plants obtained by Soxhlet extraction were analyzed by the developed high-performance liquid chromatography-diode-array detection method. Lupeol, the anti-inflammatory triterpene, was selected as a chemical marker for this investigation. All extracts together with that compound were further evaluated for their potential on anti-inflammatory activity using 5-lipoxygenase inhibition assay. Lupeol in each extract was quantified and expressed in the range of 21.44 ± 0.89-40.72 ± 0.40 mg per 100 g of crude drug and the enzyme inhibitory activity of all tested extracts presented as half-maximal inhibitory concentration values ranged between 63.71 ± 2.09 and 91.09 ± 1.40 μg/mL. This study shows that the developed analytical method is effective for analyzing triterpene lupeol in these plants and also reveals the relationship between a lupeol content and the anti-inflammatory effect.