keywords: Gossypium hirsutum, MRSA, extract, antimicrobial
The study was conducted to determine the antimicrobial efficacy of the crude methanolic extract and alkaloid fraction of the leaf of Cotton plant (Gossypium hirsutum) against methicillin- resistant Staphylococcus aureus. Phytochemical screening was carried out to check for secondary metabolites following standard procedures and agar well diffusion technique was used to evaluate the sensitivity of the isolates to the crude extract and alkaloid fraction. New effective antimicrobials are needed; natural products can be a source of potential antimicrobial agents against S. aureus, especially MRS. Phytochemical screening on the methanolic crude extract of the Cotton plant (Gossypium hirsutum) leaves revealed the presence of alkaloids, steroids, reducing sugars, amino acids, tannins, terpenoids, saponins and general glycosides. The treatment with significant activity was the 400 mg/ml of the crude extract (antibacterial) with the highest zone of inhibition of 16 mm. The cloxacillin disc was used to check for the sensitivity of the bacteria, the bacteria showed 100% resistance to the cloxacillin sensitivity disc. The result of the antimicrobial effect of the crude extract showed the sensitivity of the bacteria to the crude extract in this order, Isolates 24>32>33>25 with mean zones of inhibition ranging from 4 to 16, 4 to14, 4 to 13, 4 to 8 mm, respectively. No antimicrobial activity was exerted on the bacteria strains by the alkaloid fraction. There was a significant difference between the activity of the methanol extract and the antibacterial disc against these bacteria at the average zones of inhibition. This study indicates that Gossypium hirsutum leaf might be a potential source of novel antimicrobial agent against MRSA and methanol was a good extracting solvent for the active phytochemicals from this plant.