Isolation and characterization of compounds from the leaves of melia azedarachand stem bark of albizia schimperiana and evaluation for antimicrobial activities

Abstract

Infectious diseases remain a major threat to public health. Despite tremendous progress in human medicine, their impact is particularly great in developing countries because of the relative unavailability of medicines and the emergence of widespread drug resistance. Traditional medicinal plants are an important component in the provision of primary health care due to their worldwide availability and fewer side effects. They serve as an alternative to conventional medicines. Thus, the present study was focused on isolation and characterization of compounds from two plants namely; Melia azedarach and Albizia schimperiana. Accordingly, the leaves of Melia azedarachand stem bark of Albizia schimperianawere extracted using chloroform/methanol (1:1, v/v) to afford crude extracts. The crude extracts were also subjected to phytochemical analysis for the presence and absence of the common secondary metabolites. In line with, the leaves of Melia azedarachwas positive for alkaloids, phenols, tannins, saponins, terpenoids and steroidwhereas, the stem bark of Albizia schimperiana extract was observed to possess alkaloids, flavonoids, phenols, tannins, saponins, steroid and terpenoids.The chemical study of the leaves extract of Melia azedarach andstem bark of Albizia schimpiriana afforded two pure compounds whosestructure were established as β-sitosterol and α- spinasterol respectively, using standard spectroscopic data (1H NMR, 13C NMR, IR) and literature reports. The crude extracts and isolated compounds were subjected to biological evaluation against four bacterial strains (Bacillussubtilis, Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli) and two fungus(Aspergillus flavus and Fusariun spp.).The two characterized compounds were showed promising antimicrobial activity than the crude extract of both plant species.The observed activity was carried out at concentration of50mg/mL for the crude extracts, 20mg/mL for the isolated compounds, it would be recommended fordetermination of MICvalues provides a quantitative measure for the level of resistance expressed by the test organism.