Antioxidant and antibacterial activities of leaves and branches extracts of Tecoma stans (L.) Juss. ex Kunth against nine species of pathogenic bacteria

摘要

Tecoma stans?of the Bignoniaceae family, is an important medicinal plant. Different extracts of the leaves and branches of?T. stans?were evaluated as antibacterial potential against the growth of some human bacterial strains using the disc diffusion and minimum inhibitory concentration (MIC) methods as well as the antioxidant activity by 2,2-diphenyl-1-picrylhydrazyl?(DPPH)?method. Total phenolic and total flavonoid contents?weredetermined. The different extracts of?T. stans?were?obtained by successive solvent extraction with methanol and its fractions; ethyl acetate (EtOAc), chloroform (CHCl3),?n-butanol and aqueous. The methanol, EtOAc and CHCl3?extracts of?T. stans?showed significant effect against the tested bacteria (Bacillus subtilis,?Micrococcus luteus,Sarcina?lutea,?Staphylococcus aureus,?Escherichia coli,?Serratia marcescens,Salmonella typhi,?Proteus vulgaris?and?Pseudomonas aeruginosa). The methanol extract of the leaves exhibited the highest amount of total phenolics (50.3±3 mg gallic acid equivalents/g extract) and flavonoids (40.66±5.03 mg catechin equivalents/g extract). The EtOAc fraction of leaves and branches extracts showed the highest total antioxidant activity (%) with? 83.4±0.31 and 82.06±0.54%, respectively followed by CHCl3?fraction of leaves extracts (79.17±0.20%). These findings provide scientific evidence to support traditional medicinal uses of?T. stans?and indicate a promising potential for the development of an antibacterial and antioxidant agent from?T. stans?trees.