Antimicrobial and antioxidant activities of Psidium guajava leaves growing in Egypt

[摘要] Psidium guajava is an important edible plant, widely used in folk medicine as anti-allergy, antiplasmodial, and anticough. In the current study the total phenolic & total flavonoid contents, antioxidant and antimicrobial activities of different extracts from Psidium guajava leaves were investigated using the reported methods. The n-butanol fraction demonstrated the highest phenolic content with 547.13, followed by 397.25, 324.26, 306.12, 216.21 for 90% methanol, ethyl acetate, 100% methanol, and 85% methanol, respectively, while the lowest value of 55.13 mg gallic acid equivalent (GAE)/ g dry extract was obtained for the diethyl ether fraction. SC50 values of the n-BuOH, 90% methanol, EtOAc, 100% methanol, and 85% methanol were 13.91, 19.09, 32.13, 38.26, and 43.26 μg/ml respectively for the DPPH assay compared to 8.0 of the positive standard ascorbic acid, whereas those of the total antioxidant capacity (TAC) were 436.02, 541.0, 412.13, 394.41, and 351.91mg ascorbic acid equivalent (AAE)/g dry extract respectively. Optical density (OD) values of the reducing power antioxidant activity (RPAA) were 0.873, 0.767, 0.712, 0.681, and 0.649 respectively, compared to 0.970 of the positive standard ascorbic acid. Furthermore, the tested extracts showed noticeable antimicrobial activities against the antibiotic resistant pathogens i.e., Staphylococcus aureus (G+ve bacteria) with inhibition zones between 8-12mm, Pseudomonas aeruginosa (G-ve bacteria) with inhibition zones between 7-11mm, Candida albicans (yeast) with inhibition zones between 8-13mm, and there is no any activities were recorded against Aspergillus niger (fungi).In, conclusion the antimicrobial and antioxidant activities may be attributed to the presence of phenolic compounds.

[学科分类] 药理学