Comparison between Composition and Antibacterial Activities of Three Medicinal-Plant Extracts
Keyword : Keywords: Piper guineense, Ocimum gratissimum, Cassytha filiformis, synthetic antibiotics.
Author(s) : Obianom, A.O., Uboh Ifiok Nse., Umedum, C.U And Nwajiobi, F.O
Abstract : ABSTRACT There is now growing interest in research and development of antibacterial agents from plants to combat microbial resistance to synthetic antibiotics. Ethanol-, Ethyl acetate-, N-hexane- and Warm water- extracts of Piper guineense and Ocimum gratissimum leaves and Cassytha filiformis stem were screened for their phytochemical constituents and antibacterial activities according to standard biochemical and microbial methods. Preliminary antibacterial activity of the plants was assayed using agar well diffusion while minimum inhibitory concentrations assays were done with 200, 100, 50 and 25 mg/ml respectively for each extract against test bacteria Methicillin Resistant Staphylococcus aureus (MRSA), Methicillin Sensitive Staphylococcus aureus (MSSA), Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia, Salmonella typhi and Bacillus subtilis. Alkaloids, flavonoids saponins, tannins, phlobatannins, steroids, glycosides and quinones were detected qualitatively. Alkaloid was detected only in C. filiformis which was more extractable from ethanol than ethyl acetate and N-hexane extracts. Pathogenic bacterial isolates at concentrations of 1g of plant extracts in 1ml of dimethyl sulphoxide (DMSO) showed appreciable inhibitory activities after 24 hours of incubation at 370 C. Susceptibility tests revealed that Vancomycin (VA30) showed inhibition Zones of 6.3±1.5mm in MRSA and 5.7±2.1mm in P. aeruginosa. The Ethanol-, Ethyl acetate-, N-hexane- and Warm water-extracts of P. guineense, O. gratissimum and C. filiformis showed high rates of inhibition zones on MRSA (7.5±1.5mm), MSSA (7.1±0.5mm), E. coli (7.5±0.5mm), P. aeruginosa (6.5±1.5mm), K. pneumonia (7.0±1.5mm), S. typhi (7.0±1.0mm), and B. subtilis (6.7±0.3mm). Therefore the three plant-extracts demonstrated effective potency on selected pathogenic bacterial isolates. This study has showed that the test plants which are popular in Nigeria folk-medicine demonstrated good antimicrobial properties by their antibacterial effectiveness on the tested bacterial isolates. Further research is necessary to quantify accurate prophylactic and therapeutic doses and appropriate methods for their synthesis, presentation, and extended shelf-life.