ANTIMICROBIAL ACTIVITY OF STRYCHNOS HENNINGSII (GILG) LOGANIACEAE LEAF AND ROOT AQUEOUS EXTRACTS

Abstract

Strychnos henningsii (Gilg) Loganiaceae plant extract has been used for treatment of various ailments such as rheumatism, gastrointestinal complications and syphilis. It is also used to prepare milk soups and fatty-meat. S. henningsii leaf and root water extracts have bioactive chemicals. This study was carried to validate antimicrobial activity of S. henningsii extracts in the treatment of bacterial ailments. Antimicrobial activity of aqueous extracts was tested using isolates of bacteria (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella typhi). Commercial discs (30µg Tetracycline, 10µg Gentamycin, 30µg Kanamycin, 30µg Chloramphenicol, 30µg Augumentin, 25µg Cotrimoxazole, 10µg Ampicillin and 30µg Cenfuroxime) were used as positive controls. The antibacterial activity of aqueous extracts in concentrations of (100, 50, 25 and 12.5) µg/ml was determined by agar disc diffusion assay. The most susceptible bacteria in extracts concentration of 100µg/ml were S. typhi (11.00 ± 1.00 and 10.67 ± 1.20) mm followed by S. aureas (10.00 ± 1.00 and 9.00 ± 1.00) mm. The most resistant bacteria were P. aeruginosa and S. typhi in leaf and root extracts respectively at concentration of 50µg/ml. S. aureas was active in all extracts concentrations. The inhibition zones for antibiotics (12.00 ± 0.1 to 21.00 ± 0.3)mm were larger than those of the plant extracts (6.67 ± 0.30 to 11.00 ± 1.00)mm except for Tetracycline (7.00 ± 0.0)mm. S. aureas was resistant to Kanamycin and Chloramphenicol, S. typhi was resistant to Tetracycline and Chloramphenicol, P. aeruginosa was resistant to Chloramphenicol. Gentamycin, Tetracycline, Kanamycin and Chloramphenicol were active against E. coli. Gentamycin was active in all the bacterial strain tested. The results show considerable antimicrobial activity against the bacteria species tested. The present study justifies the use of aqueous extracts by herbalists in the treatment of diseases caused by bacterial infections.