Isolation of β-sitosterol and antibacterial analysis of hexane stem bark extract of Ficus abutilifolia (Miq.) Miq. (Moraceae)
Ficus abutilifolia (Miq), Miq. belongs to the family Moraceae and is commonly called “Large-leaved rock fig” in English. The plant is widespread in tropical and subtropical regions but a few extends into temperate regions and used traditionally to treat various ailments such as typhoid fever, chronic dysentery, sexually transmitted infections, malaria and infertility. The aim of the study was to extract stem bark of the plant using n-hexane and carry out its preliminary phytochemical screening, isolate compound(s) using chromatographic techniques and screen it for antibacterial activity using standard procedures. The preliminary phytochemical screening of the n-hexane stem bark extract revealed the presence of steroids/triterpenes. Repeated silica gel column chromatography of the n-hexane stem bark extract led to isolation of a compound coded B6 which was characterized as β-Sitosterol using spectroscopic techniques and comparison to literature data. The in-vitro antibacterial activity of the crude n-hexane stem bark extract was assayed at concentrations of 12.5, 25, 50 and 100 mg/mL using agar well diffusion and broth dilution methods against two Gram positive bacteria (Staphylococcus aureus and Baccillus subtilis) and three Gram negative bacteria (Escherichia coli, Salmonella typhi and Pseudomonas aeruginosa). The antibiotic disc used was Ciprofloxacin (5 mg/mL). The crude n-hexane stem bark extract exhibited activity against one Gram positive (Staphylococcus aureus) and one Gram negative (Pseudomonas aeruginosa) bacteria because Staphylococcus aureus exhibited susceptibility of 10.67±0.67 mm at 12.5 mg/mL and 25 mg/mL; 10.33±0.33 mm at 50 mg/mL and 11.33±0.67 mm at 100 mg/mL as compared to 26 mm at 5 µg/ml of ciprofloxacin. While Pseudomonas aeruginosa with susceptibility of 15.33±0.33 mm at 12.5 mg/mL; 14.67±0.33 mm at 25 mg/mL; 20.33±0.33 mm at 50 mg/mL and 29.67±0.33 mm at 100 mg/mL as compared to 31 mm at 5 µg/mL of the standard drug. Thus, it can be drawn that the ethnomedicinal uses of Ficus abutilifolia in the treatment of diseases related to bacterial infections has scientific basis and the antibacterial activity observed could be linked to perhaps presence of some bioactive compounds present in the plant extract.
Keywords: Antimicrobial studies, Ficus abutilifolia, NMR spectra, TLC plates, β-Sitosterol
*Correspondence: ashshekwaise@gmail.com, 0803 6304822
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