Phytochemical screening, antimicrobial, antioxidant and cytotoxic potential of different extracts of Psidium guajava leaves

Psidium guajava (Myrtaceae) is an important food crop and medicinal plant supporting its traditional uses. The aim of the present study was to evaluate phytochemical, antimicrobial, antioxidant and cytotoxic activity of various solvent extracts of leaves of P. guajava. Phytochemical analysis revealed the presence of terpenoids, tannins, steroids, flavonoids, saponins, alkaloids and highest amount of phytocompounds was reported with methanol, ethanol and acetone extract. Total phenolic and flavonoid content was found to be highest in acetone extract (256.32 ± 4.56 mg/g GAE) and n-butanol extract (198.64 ± 1.23 mg/g RE) respectively. The antimicrobial assay revealed that acetone extract (13.5 ± 2.12 mm) exhibit maximum zone of inhibition against P. aeruginosa; while acetone (14 ± 0.71 mm) and ethanol (14.5 ± 2.12 mm) showed maximum zone of inhibition against S. aureus. Chloroform extract (10.2 ± 1.13 mm) showed maximum inhibition to the growth of C. albicans. Guava leaves also possess antioxidant activity which was evaluated in terms of % DPPH (2, 2-diphenyl-1-picrylhydrazyl) free radical scavenging activity and was found highest in acetone extract (41%). Cytotoxic activity was evaluated in terms of stimulation index using bovine lymphocytes and highest stimulation index was found with methanol extract (1.432 ± 0.193). This study revealed that acetone extract of guava leaf comprises effective antimicrobial, antioxidant and cytotoxicity and can be used for therapeutic applications. © 2020, Society for Plant Research.