Abstract

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).