Phytochemical screening and evaluation of in vitro antioxidant and antimicrobial activities of the indigenous medicinal plant Albizia odoratissima

Abstract

Context: Albizia odoratissima (L. f.) Benth has been used in Indian folk medicine to treat numerous inflammatory pathologies, such as leprosy, ulcers, burns and asthma. Objective: To evaluate the antioxidant and antimicrobial properties of A. odoratissima. Materials and methods: Dried leaves of A. odoratissima were extracted in organic solvents (hexane, chloroform, ethyl acetate, and methanol). The total phenolic content (TPC) and total flavonoid content (TFC) were determined using the Folin-Ciocalteu and aluminum chloride colorimetric methods, respectively. The antioxidant activity was examined using 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydrogen peroxide (H2O2), 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS), and ferric reducing antioxidant power (FRAP) assays. The antibacterial activity was examined using minimum inhibitory concentration (MIC) and the minimum bacterial concentration (MBC), determined by broth microdilution method against Gram-negative bacteria (Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, and Proteus vulgaris) and Gram-positive bacterium (Staphylococcus aureus). Results: The TPC ranged from 4.40 ± 1.06 to 1166.66 ± 31.85 mg GAE/g of dry weight (DW), and the TFC ranged from 48.35 ± 3.62 to 109.74 ± 1.84 mg QE/g of DW. The IC50 values of the ethyl acetate extract for DPPH, ABTS, and H2O2 were 10.96 ± 0.40, 4.35 ± 0.07, and 163.82 ± 1.52 μg/mL, respectively. Both methanol and ethyl acetate extracts demonstrated effective antibacterial activity with MICs and MBCs values ranging 136–546 μg/mL and 273–1093 μg/mL, respectively, against the tested pathogenic species. Conclusions: The leaves of A. odoratissima showed potent free radical scavenging property and antimicrobial activity.

Keywords

• agar well diffusion
• radical scavenging activity
• total phenolics
• total flavonoids
• secondary metabolites