Inhibition of growth of antibiotic-resistant Staphylococcus sp. and Proteus sp. by mangrove plant extracts

Abstract

Mangrove plants Avicennia marina, Bruguiera sexangula, Derris trifoliata, Excoecaria agallocha, Lumnitzera racemosa and Rhizophora apiculata were used to obtain plant extracts by grinding and sequential Soxhlet extraction method. Plant extracts were obtained from mature leaves, immature leaves, shoot and bark of above selected mangrove plants. In sequential Soxhlet extraction method, plant extracts were obtained in petroleum ether, chloroform, ethyl acetate, ethanol and water. The antibacterial activity of these mangrove plant extracts was tested against antibiotic-resistant bacterial species of Staphylococcus sp. and Proteus sp. The degree of antibacterial activity was assayed by measuring the length of inhibition zone in millimeters. Ethanol extracts were found to be much more effective on both bacterial strains than aqueous extracts in grinding procedure. In Soxhlet extraction method, almost all plant extracts could inhibit growth of Staphylococcus sp more than Proteus sp. Among the plant extracts, the most clear antibacterial activity was observed extracts of L. racemosa against both bacterial strains. Soxhlet extracts of fresh plant materials and charcoal treated Soxhlet plant extracts of L. racemosa were able to inhibit both bacterial strains more than those of dried Soxhlet extracts of plant materials and untreated Soxhlet plant extracts. Antibacterial activity of plant extracts of both fresh and dried plant materials had been reduced for both bacterial strains with the time after extraction. The biological active compounds in plant extracts will be isolated, purified and characterized using chromatographic methods and known spectroscopic techniques.