…tude toxicologique et Èvaluation des activitÈs biologiques des extraits de Teucrium chamaedrys L.

Abstract

Teucrium chamaedrys L., locally known as ´Balut al ardª is a plant widely used in traditional medicine. The present work aims to determine the total polyphenol and flavonoid content, evaluate toxicity, and some biological activities (antioxidant, antibacterial, anti-inflammatory, and analgesic) of extracts of this plant. The first step in the extraction process involved soaking the plant powder in a mix of water and methanol, which produced a raw extract (EB) with a yield of 18.05%. The latter was subjected to successive fractionation using solvents of increasing polarities, resulting in four distinct fractions: hexane (EH), chloroformic (EC), ethyl acetate (EAE) and aqueous (EA). Colorimetric analysis showed that the ethyl acetate (EAE) extract had the highest levels of total polyphenols (370.49 ± 15.84 ¿g GAE/mg of extract) and total flavonoids (70.98 ± 1.00 ¿g QE/mg of extract). The results of the antioxidant activity showed that the aqueous extract (EA) showed a remarkable antioxidant capacity (CAT = 793.5 ± 2.19 ¿g AAE/mg), while the EAE extract showed a high anti-radical power against the radicals DPPH and ABTS (CI = 12.5 ± 1.00 ¿g/mL and 123.9 ± 1.36 ¿g/mL, respectively), as well as a strong reducing power (A .5= 58.15 ± 1.87 ¿g/mL). The results of antibacterial activity showed moderate EB and EAE activity against E. coli (11 ± 1.41 mm and 9.33 ± 0.57 mm, respectively). The in vivo acute toxicity test of EB showed that it is safe, with an LD50 greater than 2000 mg/kg, and did not show any signs of toxicity or changes in biochemical parameters. On the other hand, the evaluation of the in vivo anti-inflammatory activity of EB in the xylene-induced atrial oedema model showed a dose-significant reduction in oedema formation, the most important dose being 500 mg/kg (75.24 ± 2.20%). The analgesic effect of EB at doses of 250 and 500 mg/kg was evaluated by the Koster method following the injection of acetic acid. The results of EB showed a significant dose-dependent effect, with the highest percentage being obtained at the 500 mg/kg (77.65 ± 2.35%) dose, which is similar to that of Diclofenac sodium (78.51 ± 1.12%). In conclusion, these results validate the traditional use of Teucrium chamaedrys L. and suggest that this plant could be a valuable source of natural compounds for medical use, needing more research in pharmacology.