Antibacterial activity and GC–MS profiling of Stephania glandulifera Miers root extract

Stephania glandulifera is an important medicinal herb of the Menispermaceae family. Traditionally, its rhizome extract has been used for the treatment of various ailments and diseases, however, there is no scientific evidence to substantiate these claims. This study evaluated the antibacterial properties of the methanolic root extract of Stephania glandulifera against two Gram-positive organisms (Bacillus subtilis, Staphylococcus aureus), and two Gram-negative organisms (Escherichia coli, Pseudomonas aeruginosa) using agar disc diffusion and broth microdilution methods. The bioactive compounds within the extract were identified through gas chromatography and mass spectroscopy (GC–MS) analysis. The results indicated a significant antibacterial effect of the methanolic extract against all tested microorganisms. The methanolic extract demonstrated pronounced antibacterial activity, with inhibition zones ranging from 21 to 23 mm against Staphylococcus aureus and Escherichia coli, and moderate activity against Bacillus subtilis and Pseudomonas aeruginosa (17–19 mm). The fraction exhibited antibacterial activities with minimal inhibitory concentration (MIC) values ranging from 3.9 to 15.6 μg/ml; showing the strongest activity against Staphylococcus aureus (3.9 μg/ml) and Pseudomonas aeruginosa (7.8 μg/ml). Twenty-eight bioactive compounds were detected in root methanolic extract by GC–MS. The major potent compounds identified in root extracts were Adipic acid, 2-ethylhexyl pentadecyl ester (100%), Dodecane, 1-fluoro-(36.17%), Benzoic acid, 4-methyl-2-trimethylsilyloxy-, trimethylsilyl ester (36.20%). These results show that the root extract of S. glandulifera exhibited significant antibacterial activity against both gram-positive and gram-negative bacteria, validating its medicinal claims. While these in vitro effects are promising, further microbiological and pharmacological evaluations are necessary to fully understand its potential.