In-vitro assessment of antioxidant and antimicrobial activities of methanol extracts and essential oil of Thymus hirtus sp. algeriensis.

ABSTRACT

BACKGROUND: Owing to the complexity of the antioxidant materials and their mechanism of actions, it is obvious that no single testing method is capable of providing a comprehensive picture of the antioxidant profile. The essential oil of the Thymus specie may still possess other important activities in traditional medicine, it can be used in the treatment of fever and cough. This essential oil may also have an anticancer activity. METHODS: The essential oils aerial parts hydrodistilled from Thymus hirtus sp. algeriensis, were characterised by GC/MS analysis and the methanolic extracts were chemically characterized by HPLC method. The essence of thyme was evaluated for its antioxidant and antibacterial activity. RESULT: The Terpinen-4-ol are the principal class of metabolites (33.34%) among which 1.8-cineole (19.96%) and camphor (19.20%) predominate. In this study, quantitative values of antioxidant activity of crude methanolic extracts of Thymus hirtus sp. algeriensis were investigated. The essential oils was screened for their antibacterial activity against six common pathogenic microorganisms (Escherichia coli, Pseudomonas aeruginosa, Salmonella enteridis, Staphylococcus aureus, Bacillus subtilis and Listeria monocytogenes) by well diffusion method and agar dilution method (MIC). All the essences were found to inhibit the growth of both gram (+) and gram (-) bacteria organisms tested. These activities were correlated with the presence of phenolic compounds in active fractions. HPLC confirmed presence of phenolic compounds in methanol extracts. CONCLUSION: Methanol extracts and essential oils from aerial parts of Thymus hirtus sp. algeriensis, were examined for their potential as antioxidants. The technique for measuring antioxidant activity, which was developed using DPPH, ABTS and ß-carotene bleaching, produced results as found in established literatures. The present results indicate clearly that methanol extracts and essential oils from Thymus hirtus sp. algeriensis possess antioxidant properties and could serve as free radical inhibitors or scavengers, acting possibly as primary antioxidants, also their essential oil have an antibacterial effect.