Antibacterial activity and phytochemical analysis of Kembang semangkok (Scaphium macropodum) stem bark

Scaphium macropodum (S. macropodum) belongs to the Sterculiaceae family. Different parts of this plant are used traditionally to treat several diseases such as cancer, asthma, cough, dysentery, gastroenteritis, diarrhoea, fever, inflammation, and sore throat. This study was conducted to determine the antibacterial activity, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and identify the chemical constituents of methanol extract of S. macropodum. The inhibitory activity of the extract was tested against Bacillus subtilis (B. subtilis), Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), Salmonella typhimurium (S. typhimurium) and Mycobacterium smegmatis (M. smegmatis) by disc diffusion assay. Broth microdilution assay was used to determine the MIC and MBC, and the extract was subjected to the gas chromatography-mass spectroscopy (GC-MS) to identify the chemical constituents. The results showed that S. aureus displayed the largest zone of inhibition (10.67 ± 0.58 mm), and negative zone of inhibition was observed with E. coli and S. typhimurium in agar disk diffusion assay. S. aureus showed the lowest MIC (0.78 mg/mL) and MBC (3.13 mg/mL). The GC-MS analysis of S. macropodum methanol extract showed the presence of at least four bioactive compounds i.e. 1-methyl-trans-decahydroquinol-5(equat)-ol, hexadecanoate methyl, hexadecanoic acid , and phthalic acid, di(2,4,4-trimethylpentyl) ester. The findings from this study suggested that S. macropodum could be a promising candidate for antibacterial agent due to its bactericidal property and can be further investigated.