Antihyperlipidemic Constituents of Indonesian Medicinal Plant, <i>Pterospermum javanicum</i> Jungh.

Background: Indonesia, an archipelagic nation, is home to the second-highest biodiversity in the world, which includes Bajur (Pterospermum javanicum Jungh.) leaves, which has been used to treat lipid metabolic disorders. To the best of our knowledge, there is no report on P. javanicum Jungh regarding its antihyperlipidemic potency and its chemical constituents. This study aims to evaluate the antihyperlipidemic activity of the P. javanicum methanolic leaves extract, its fractions and its constituents. Methods: The P. javanicum leaves extraction was performed using maceration and liquid-liquid extraction method. The major constituent of the ethyl acetate fraction was isolated using column chromatography and further purification using high performance liquid chromatography (HPLC) and its structure was elucidated through nuclear magnetic resonance (NMR). The antihyperlipidemic activities of isolated compounds were evaluated using computational studies by mean binding affinity with lipase (1LPB) enzymes, in which their potency was compared against the standard drugs, orlistat. Antihyperlipidemic activity of P. javanicum extracts were screened using lipase enzyme inhibition assay. The antioxidant activity was evaluated using 2,2-Diphenyl-1-picrylhydrazyl (DPPH) scavenging reaction. Results: The in vitro study showed the ethyl acetate fraction significantly inhibited the lipase enzyme and free radicals with an IC50 value of 1.84±0.09 µg/mL and 76.67±1.37 µg/mL, respectively. Two flavonoids, kaempferol-3-O-rhamnoside 1 and quercetin-3-O-rhamnoside 2 were successfully isolated and elucidated with stronger binding affinity with 1LPB enzymes than orlistat. Conclusion: The study confirmed P. javanicum leaves potency as source for antihyperlipidemic and antioxidant agents.