Content of Polyphenolics Constituents and the Antioxidant and Antimicrobial Activities of Extracts from Leaves and Fruits of Lannea microcarpa Engl. & K. Kraus (Anacardiaceae)

摘要

Nowadays, a number of studies on health benefits associated with natural compounds have been demonstrated. Polyphenolics in fruits, leaves, herbs and vegetables possess potent antibacterial and antioxidant activities. In the present study, a portion of Lannea microcarpa's lyophilised fruits and leaves aqueous acetone extract, was fractionated by successive liquid-liquid partitioning to obtain ethyl acetate and n-butanol fraction. The total polyphenolic constituents and total flavonoid constituents from the extract and the two fractions were determined and were found to be the highest respectively in leaves butanol fraction (22.05±0.78 mg GAE/100 mg) for polyphenolic constituents, and in leaves and fruits ethyl acetate fraction (1.61±0.02 mg QE/100 mg) for the flavonoids constituents. Antioxidant activity of the extract and the two fractions were determined by in vitro model using DPPH; Antibacterial activity of these extracts and fractions was also assayed on two Gram+ bacteria and six Gram-bacteria by using disc diffusion and broth micro dilution method. Data indicated highest antioxidant activity obtained from leaves extracts and fractions IC50 (1.55±0.19 μg/mL), and inhibitory effect both on Gram- and Gram+ bacteria with highest antibacterial activity MIC (0.15625 mg/mL), obtained with leaves ethyl acetate and n butanol fraction on Bacillus cereus (ATCC 9144). All the results obtained from this study, showed that Lannea microcarpa's fruit and leaves extract could be candidate for news antibacterial and antioxidant compounds.