DOI: https://doi.org/10.55373/mjchem.v25i4.155

Keywords: Antibacterial activity; chalcone; flavanone; flavone; Muntingia calabura

Abstract

Muntingia calabura (Eleocarpaceae) is a medicinal plant that has gained interest due to its various pharmacological activities. The aim of this work was to isolate chemical constituents from the leaves of M. calabura and evaluate their antibacterial activity. Initially, the dried leaves were extracted with 95% ethanol, followed by water/ethyl acetate (EA) partitioning. The EA crude extract was then subjected to continuous column chromatography over silica gel. Anti-bacterial activity was determined by micro broth dilution. Ten known flavonoids comprising three flavanones {(2S,3S) 3,5-dihydroxy-7-methoxyflavanone (FA1), (2R,3R) 3,5,7-trihydroxy-flavanone (FA2), (2S) 7,8-dihydroxyflavanone (FA3)}, three chalcones {2’,4’-dihydroxy-3’-methoxychalcone (C1), 2’,4’-dihydroxychalcone (C2), 2’,3’,4’-trihydroxychalcone (C3)} and four flavones {3,5-dihydroxy-7,8-dimethoxyflavone (F1), 3,5,7-trihydroxy-8-methoxyflavone (F2), 5-hydroxy-3,7-dimethoxyflavone (F3), 5,7-dihydroxyflavone (F4)} were obtained from this work. The structures were identified using spectroscopic methods and compared with literature data. Among the isolates, compounds FA1, FA3, and C3 were isolated for the first time from M. calabura. Antibacterial activity showed that compounds C1 and C2 exhibited moderate activity with a MIC value of 32.5 µg/ml against Bacillus cereus. This study can serve as reference guide for drug development and highlights the potential of M. calabura leaves as an antibacterial agent.