Phytochemical, Antimicrobial, and Toxicological Evaluation of Traditional Herbs Used to Treat Sore Throat

The in vitro antibacterial activities of 29 traditional medicinal plants used in respiratory ailments were assessed on multidrug resistant Gram-positive and Gram-negative bacteria isolated from the sore throat patients and two reference strains. The methanolic, n-hexane, and aqueous extracts were screened by the agar well diffusion assay. Bioactive fractions of effective extracts were identified on TLC coupled with bioautography, while their toxicity was determined using haemolytic assay against human erythrocytes. Qualitative and quantitative phytochemical analysis of effective extracts was also performed. Methanolic extract of 18 plants showed antimicrobial activity against test strains. Adhatoda vasica (ZI = 17-21 mm, MIC: 7.12-62.5 μg/mL), Althaea officinalis (ZI = 16-20 mm, MIC: 15.62-31.25 μg/mL), Cordia latifolia (ZI = 16-20 mm, MIC: 12.62-62.5 μg/mL), Origanum vulgare (ZI = 20-22 mm, MIC: 3-15.62 μg/mL), Thymus vulgaris (ZI = 21-25 mm, MIC: 7.81-31.25 μg/mL), and Ziziphus jujuba (ZI = 14-20 mm, MIC: 7.81-31.25 μg/mL) showed significant antibacterial activity. Alkaloid fractions of Adhatoda vasica, Cordia latifolia, and Origanum vulgare and flavonoid fraction of the Althaea officinalis, Origanum vulgare, Thymus Vulgaris, and Ziziphus jujuba exhibited antimicrobial activity. Effective plant extracts show 0.93-0.7% erythrocyte haemolysis. The results obtained from this study provide a scientific rationale for the traditional use of these herbs and laid the basis for future studies to explore novel antimicrobial compounds.