ANTIBACTERIAL ACTIVITY AND LC-MS IDENTIFICATION OF QUERCETIN IN THE ETHYL ACETATE FRACTION OF Polygonum barbatum L. LEAVES FROM CENTRAL KALIMANTAN, INDONESIA

Mengkrengan (Polygonum barbatum L.) is a plant that is empirically used by the Dayak tribe in Kapuas Village, Central Kalimantan, Indonesia, for the treatment of typhoid fever. Secondary metabolites found in the leaves of mengkrengan include saponins, terpenoids, flavonoids, tannins, and alkaloids. The objective of this study was to determine the antibacterial activity and identify the metabolite compounds from the ethyl acetate fraction of mengkrengan (Polygonum barbatum L.) leaves originating from Central Kalimantan, Indonesia, using the Liquid Chromatography – Mass Spectrometry (LC-MS) method. The stages of the research began with the preparation of simplicia, the production of the ethyl acetate fraction, antibacterial activity testing at concentrations of 5%, 10%, and 15%, and the identification of metabolite compounds from the ethyl acetate fraction of mengkrengan leaves using LC-MS. The results obtained at concentrations of 5%, 10%, and 15% showed antibacterial activity with inhibition zones of 9 mm (moderate category), 12 mm (strong category), and 17 mm (strong category), respectively. LC-MS identification of compounds revealed a metabolite compound with the molecular formula C15H10O7 (MW 303.0511), which was identified as quercetin. The LC-MS chromatogram also showed the presence of six other unidentified compounds.