Anti-inflammatory activity of organic acids from the seeds of Phaseolus lunatus L.

A new sesquiterpene acid, named dihydrophaseic acid A (1), along with four known organic acids, p-hydroxybenzoic acid (2), vanillic acid (3), dihydrophaseic acid (4), and 4-methylpyrazole-3-carboxylic acid (5), were obtained by isolation and purification from the ethyl acetate extract of the seeds of Phaseolus lunatus L. (Fabaceae). The structural elucidation of the new sesquiterpene acid was performed using a variety of spectroscopic methods (HRESIMS, UV, IR, 1D and 2D NMR) and ECD calculations. All compounds were evaluated for in vitro anti-inflammatory activity using mouse mononuclear macrophages cells (RAW264.7). The anti-inflammatory evaluation demonstrated that the new compound exhibited moderate NO inhibitory effect on lipopolysaccharide (LPS)-stimulated RAW264.7 cells with IC₅₀ value of 28.30 ± 0.76 µM, compound 5 displayed the most active inhibitory activity with an IC₅₀ value of 5.55 ± 0.79 µM.