| Obesity is a prevalent metabolic disorder that is induced by inflammatory responses that lead to the increased levels of pro-inflammatory mediators, including interleukin-6 (IL-6) and leptin. Pithecellobium jiringa or jengkol, is a functional tropical plant in Southeast Asia regions including Indonesia that has been for culinary and traditional medicines. This research was aimed to identify chemical constituents of protein fractions from P. jiringa peel and seed by using pyrolysis gas chromatography mass spectrometry (py-GC/MS), and their inhibitory effects at various concentrations (5-100 µg/ml) on IL-6 and leptin expression in mouse 3T3-L1 preadipocytes by conducting the enzyme-linked immunosorbent assay (ELISA). Both protein fractions from P. jiringa peel and seed consisted of amino acid derivatives, including alanine ethyl ester (peel part), dimehylamine, piperidine, aziridine, and phenyl acetyl glutamine (seed part). Protein fractions from P. jiringa peel at 25 µg/ml decreased >50% leptin expression in 3T3-L1 preadipocytes compared to that of seed protein fractions. Meanwhile, seed protein fraction dose-dependently inhibited IL-6 expression. At 10 µg/ml, seed protein fraction reduced up to 50% IL-6 production, respectively. Our results suggest that protein fractions from both P. jiringa peel and seed may have potential anti-obesity effects on 3T3-L1 preadipocytes via attenuating IL-6 and leptin expression. P. jiringa protein fractions can be used as alternative food supplements for reducing the risk of obesity. |