Antimycobacterial and antibacterial activities <i>Macaranga gigantea</i> stem methanolic extract and its GC-MS profiling

Abstract

The increase in antibiotics resistance is a serious health issue that escalated the difficulty of bacterial infection control. There is hope for developing alternative medicines for the various bacterial infections treatment using medicinal plants. Macaranga gigantea is a medicinal plant that has been used widely as a folk medicine in the treatment of a cough, fever, stomach aches, and inflammation. The study was aimed to evaluate the antimycobacterial and antibacterial activity followed by phytochemical profiling using Gas chromatography - Mass spectrometry (GS-MS) of M. gigantea stem methanolic extract. The disk diffusion assay was carried out to evaluate the anti-mycobacterial and anti-bacterial activity. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined using tetrazolium microplate assay method. GS-MS profiling was done to identify the chemical constituents in the extract. The finding showed that S. aureus (IZD= 15.00 ± 0.00 mm) was the most sensitive to methanol extract of M. gigantea, followed by M. smegmatis (IZD= 14.67 ± 0.58 mm). The extract exhibited the lowest MIC against S. aureus (1.56 mg/ml) while no inhibition occurred at all against Salmonella typhimurium. The GC-MS profiling of methanol extract of M. gigantea demonstrated the presence of at least 33 chemical constituents. The major compounds were 2-Isopropoxyphenol (6.71%), hexadecanoic acid (5.83%), 12-Hydroxystearic acid (4.49%), ketone, methyl 2- methyl-1,3-oxothiolan-2-yl (4.45%), 2,4-dihydroxy-2,5-dimethyl-3(2H)-furan-3-one (2.85%), phenol, 2-ethyl-4,5- dimethyl- (2.70%) and cyclopentadecanone, 2-hydroxy- (2.44%), among others. The study revealed that M. gigantea methanolic extract displayed both antimycobacterial and antibacterial activity with wide range of compounds in the extract.