Evaluation of antioxidant and antibacterial effect of methanolic extract from thyme (Thymus vulgar), senna (Cassia angustifolia) and licorice (Glycyrrhiza glabra)

Thymus vulgar، Cassia angustifolia and Glycyrrhiza glabra are widely used in the East Azerbaijan folk medicine. Effective compounds present in these plants could be candidates for some of their biological activities and therefore for their therapeutic uses. In this study، methanolic extract of these plants was used to detect their antioxidant and antimicrobial activity.

Methanolic extract of the dried powder was obtained by maceration method. Then، the solvent was removed by rotary evaporator. As antioxidant activity test، superoxide anion radical scavenging level was measured by a pyrogallol auto-oxidation system. The antibacterial activity of methanolic extract of these plants was tested by disc diffusion method against 3 enteric microorganisms. The minimal inhibitory concentrations (MIC) and the minimum bactericidal concentration (MBC) of methanolic extracts were also determined.

The antioxidant activity of methanolic extract of Thymus was dose-dependent; The Cassia also showed antioxidant properties in small quantities، but no specific antioxidant activity of Glycyrrhiza extract was observed. The three microorganisms were sensitive to the methanolic extract of these plants and showed 4 to 15 mm zone of inhibition.

Thyme has both stronger antioxidant and antibacterial activities than the other two plants. Generally، different results obtained for each plant depend on several factors such as amount of active ingredients contained in each plant and it also depends on genus and the family of plants، type of solvent and extraction method.