Phytochemical Investigation and Antibacterial activity of Stem Bark Extract of Cordia africana

Abstract

Drug discovery involves the identification of new chemical entities of potential therapeutic value, which can be obtained through isolation from natural sources. The use of plants as medicines has a long history in the treatment of various diseases. Cordia africana is one of the main sources of traditional medicines serving to cure different diseases for human being and domestic animals. For example, it helps to cure cough, toothache, stomach ache, fire burn, Michi, diarrhea, jaundice, eye infection, tonsillitis, eye-problem, anthrax of cattle, treat tuberculosis, asthma, skin rash, smell of foot, scabies. In this study, the stem bark of the plant was successively extracted using n-hexane, chloroform and methanol. Methanol extract was found to be more active against bacteria indicating that the antibacterial component(s) of the sample may be residing in the methanol extract. The methanol crude extract was fractionated and purified using column chromatography with increasing polarities of chloroform-methanol mixture through frequent TLC analysis and two compounds were isolated and characterized. The structure of the isolated compounds were characterized by using 1HNMR 13CNMR, and DEPT experiments. The crude extracts and isolated compounds were evaluated for their in vitro antibacterial activity against Staphylococcus aureus, a Gram-positive bacteria and three Gram-negative strains Escherichia coli, Pseudomonas aeroginosa and Kleblesia pnuemonia using agar diffusion method. Crude extract of chlorofrom and n-hexane displayed pronounceable activity against S. aureus and E. coli with inhibition zones of 8mm and 9mm respectively, while the methanol extracts displayed superior activity with 12 and 10 mm zone of inhibition against S. aureus and E. coli respectively. In this study two compounds isolated, (2) were isolated. The result is significant compared with ceftriaxone used as positive control and DMSO used as negative control.