Determination of phenolic content, antioxidant activity, and antimicrobial properties of 'zhourat using variable extraction conditions

Abstract

Herbal infusions are very common home remedies used since ancient times for treating several diseases at home. Zhourat is one of those herbal teas popular among populations of the Middle East that consist of a mixture of different parts of many plants. The purpose of our study was to find the best extraction conditions to get phenolic compounds form these plants, and analyse extracts of those plants and of the Zhourat mixture for antioxidant and antimicrobial properties, in order to determine any synergistic effect in the mixture that justifies the consumption of a combination of plants. Different solvent and temperature conditions were used for extraction at a constant time and analysis was performed on the extracts. No synergistic effect appeared in the Zhourat mixture as a whole, neither for the antimicrobial assay, nor the antioxidant test. In addition, optimal extraction conditions differed between different plants, but a mixture of 50% water/ 50% ethanol at 40 °C appeared to be optimal for the samples tested. The total phenolic content ranged between 0.2 mg GAE / g for Shabshul dara and 11.4 mg GAE / g for Mallisse. In contrast, Zer Wared and Wared extracts at 40 ˚C showed the highest free radical scavenging activity with the three solvents used, whereas Sekkar nabet had the lowest antioxidant effects. For both total phenolic content and anti-radical properties, Zhourat extracts did not show an additional effect over individual plants, and results fell in mid-range. At last, as for the antimicrobial effect, Zhourat mixture showed antibacterial properties against S. Aureus and E. coli, and these antibacterial properties varied among the individual plants as well. The results suggested that the most available herbal infusions in Lebanon might be better consumed alone, rather than in a Zhourat Mixture.