In vitro antimicrobial and antioxidant activity of acetone and methanol extracts from Thymus leucotrichius (Lamiaceae)

Abstract

Background and Objectives: Thymus species has been used as tonic and herbal tea, antiseptic, antitussive, carminative, antioxidant, anti-inflammatory and antimicrobial activities. The acetone and methanol extracts of Thymus (T.) leucotrichius (Labiatae/Lamiaceae) was examined for antimicrobial and antioxidant properties. Materials and Methods: The antioxidant properties of acetone and methanol extracts of Thymus leucotrichius were investigated using 1,1-diphenyl-2-picrylhydrazyl (DPPH)/nitric oxide (NO) radical scavenging activity, reducing power and total phenolic substance analysis. Antibacterial, antiyeast and antifungal activity of the plant extracts were tested using the disc diffusion method. Results and Discussion: Results showed that IC50 of Thymus leucotrichius acetone and methanol extracts that scavenged 50% of the DPPH radical in the medium was found to be 109.72 mu g/ml, 43.53 mu g/ml, respectively. It was found that IC50 of Thymus leucotrichius acetone and methanol extracts which scavenged 50% of the NO radical in the medium was 180.56 mu g/ml, and 67.34 mu g/ml, respectively. In the Thymus leucotrichius acetone and methanol extracts (1 mg), 35.64 mu g and 51.78 mu g pyrocatechol equivalents of phenols were detected, respectively. Neither acetone nor methanol extract possessed activity towards Proteus vulgaris, Rhodotorula rubra, Candida albicans, Aspergillus parasiticus and Aspergillus niger. Acetone extract was the most active on Bacillus cereus and Bacillus megaterium. The sentivity was also observed against towards Escherichia coli H7:O157, Kluvyeromyces fragilis and Fusarium proliferatum when acetone extract used. The methanol extract also displayed more or less similar inhibitory activity towards the test microorganisms. Kluvyeromyces fragilis was resistant to methanol extract of the species unlike acetone extracts of the species. However, the fungus Fusarium proliferatum was markedly inhibited by the methanol extract of test species at 1000 mu g and above. Significant inhibitory activities of the two extracts were based upon the increasing dose-dependent level.