This study sought to investigate the importance of the inhibitory effect of medicinal plant extracts synergistically with algae extracts against pathogenic microbes. Herein, in vitro antibacterial effects of the Mentha spicata and Cladophora glomerata extracts underwent evaluation against three bacterial strains, i.e., Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. The antibacterial activity of each extract, tested alone and in combination, helped evaluate their synergistic antibacterial potential. The results revealed the M. spicata extract alone has higher antibacterial potential against all the tested bacterial strains than the C. glomerata extract. Both extracts in combination showed a higher synergistic antibacterial activity against all bacterial strains than those of the standard drugs gentamicin and ciprofloxacin. Gas chromatography-mass spectrometry (GC-MS) analysis authenticated the presence of different bioactive compounds, including 14 species of saturated, monounsaturated, and polyunsaturated fatty acids in the M. spicata extract. However, eight fatty acids were in the C. glomerata extract, as well as some essential oils, hydrocarbons, and sesquiterpenoids. The potent synergistic antibacterial effects of both extracts could most likely refer to the combined activity of bioactive constituents, especially palmitic, behenic, linolenic, oleic, arachidonic, 7-hexadecenoic, hexanoic, doconexent, and tetradecanoic fatty acids.
Mentha spicata, Cladophora glomerata, fatty acids, antibacterial potential, synergistic effects
In the presented study, the remarkable combined antibacterial activity of the M. spicata and C. glomerata extracts revealed the synergistic effects of their bioactive compounds against the tested bacterial strains.