Effect of temperature and extraction process on antioxidant activity of various leaves crude extracts of Thymus vulgaris

Objective:To observe the effect of temperature and extraction process on the estimation of antioxidant activity of various organic crude extracts from the leaves of Thymus vulgaris(T.vulgaris)species native to Sultanate of Oman.Methods:The dry powder samples of T.vulgaris were extracted with methanol using two different extraction methods.Both methanol crude extracts from the leaves of T.vulgaris were defatted with water and extracted successively with different polarities of solvents with increasing polarities,e.g.,hexane,ethyl acetate,chloroform and butanol.Results:The yield of methanol crude extract by Soxhlet extraction method is better than maceration method.The yield of extraction was increasing with increasing temperature.The antioxidant activity of different crude extracts from both extraction methods was measured by DPPH with modification.By Soxhlet extraction method,the activity result found in butanol crude extracts was highest and the lowest in hexane crude extract as the following order of butanol>methanol>ethyl acetate extract>chloroform>hexane extract.However,by maceration method,the activity was highest in ethyl acetate and lowest in chloroform as the order of ethyl aectate>methanol extract>butanol>hexane>chloroform.Conclusions:In conclusion,the maceration method is the best method for the evaluation of antioxidant activity.

Contribution of Water and Lipid Soluble Substances in the Relaxant Effects of Tymus Vulgaris Extract on Guinea Pig Tracheal Smooth Muscle in Vitro

Objective： To examine the relaxant effects of hydro-ethanolic, macerated aqueous （MA） and lipid- free macerated aqueous （LFMA） extract of Tymus vulgaris on tracheal chains of guinea pigs. Methods： The relaxant effects of five cumulative concentrations of each extract （0.4, 0.8, 1.2, 1.6 and 2.0 g/100 mL） were compared with saline as negative control and five cumulative concentrations of theophylline （0.1, 0.2, 0.4, 0.6 and 0.8 mmol/L） on precontracted tracheal smooth muscle of guinea pig with 60 mmol/L KCl （group 1） and 10 μmol/L methacholine （group 2, n=6 for each group）. Results： In group 1 all concentrations of theophylline, three higher concentrations of hydro-ethanolic, two concentrations of LFMA and last concentration of MA extracts showed significant relaxant effects compared with that of saline （P〈0.05 or P〈0.01）. Two lower concentrations of LFMA and all concentrations of MA except higher one caused contraction compared with saline （P〈0.05 or 0.01）. In group 2 experiments, all concentrations of theophylline, hydro-ethanolic, MA and LFMA extracts showed significant relaxant effects compared to that of saline （P〈0.05 or P〈0.01）. In both groups, the relaxant effect of all concentrations of hydro-ethanolic extract were significantly higher than most concentrations of others （P〈0.05 or P〈0.01）. The relaxant effect of different concentrations of three extracts were significantly greater in group 2 compared with group 1 experiments （all P〈0.01）. There were significantly positive correlations between the relaxant effects and concentrations for theophylline and all extracts in both groups （P〈0.05 or P〈0.01）. Conclusion： Hydro-ethanolic extract has a potent weaker relaxant effect for other extracts from Tymus vulgaris on tracheal chains of guinea pigs.