Antibacterial, antioxidant and phytochemical investigation of Thuja orientalis leaves

In the present study, leaves of Thuja orientalis were powdered and extracted by soxhlet extractor in two solvent systems that is, (E1) ethyl acetate: chloroform: ethanol (40: 30: 30) and (E2) methanol: distilled water (70:30). This study conferred the screening of phytochemical constituents, antioxidant activity and antibacterial activity of crude E1 and E2extract and its fractions. Antioxidant activity was carried out by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The results indicate that E2 extract (70% methanolic extract) had the highest antioxidant effect (85.25% inhibition) at 100 µg/ml concentration and the crude extracts (E1 and E2 extract) showed significant (P ≤ 0.05) inhibitory activity against both gram positive and gram negative organisms. It was active against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Agrobacterium tumefaiens. The minimum inhibitory concentrations (MICs) of E1 extract ranged from 0.40 to 0.85 mg/ml and E2 extract 0.55 to 1.15 mg/ml. The highest antibacterial potentiality was exhibited by E2 extract. The fractions also exhibited antimicrobial activity against all the selected microorganisms. The study revealed that T. orientalis is a promising phytomedicine for antioxidant and antibacterial activity.   Key words: Thuja orientalis, 2,2-diphenyl-1-picrylhydrazyl (DPPH), extracts, fractions, minimum inhibitory concentrations (MICs).