GC-MS analysis and antimicrobial activity of the aqueous extract from the bulbs of Allium chinense G. Don. cultivated in North Sumatra, Indonesia

Chemical constituents of the aqueous extract of the Chinese shallot, Allium chinense G. Don. grown in North Sumatra, Indonesia was determined through gas chromatography-mass spectrometry (GC-MS). The aqueous extract was obtained from maceration in distilled water and concentrated using rotavapor (yield: 38%, w/v). The antimicrobial activity of the aqueous extract displayed broad-spectrum inhibition against Bacillus subtilis, Candida albicans, Staphylococcus aureus and Escherichia coli. The most potential bioactivity was its antifungal activity against Candida albicans with a minimum inhibitory concentration (MIC) of 62.5 µg/mL. The results also displayed a distinct composition in North Sumatran cultivar, Allium chinense, which previously reported to be dominated by organosulfur compounds in the Chinese shallot. Furan compounds and their derivatives dominated the composition of aqueous extract. The major components identified were 5-(hydroxymethyl)-2-furancarboxaldehyde (26.65%), 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one (14.64%), lactic acid (12.70%), 3,5-dihydroxy-2-methyl-5,6-dihydropyran (10.42%) and other furan derivatives (<2%) which may be responsible for its antimicrobial activity due to its furan cocktails in the extract. The major compound, 5-(hydroxymethyl)-2-furancarboxaldehyde is then revealed as a potential antioxidant based on literature reviews.