Evaluation Of Antimicrobial And Antioxidant Properties Of Plant Extracts From Four Algerian Lamiaceae Species: A Phytochemical Study By Hplc-Dad

Abstract

Introduction: The Lamiaceae family comprises various species with substantial therapeutic promise, largely due to their concentration in phenolic compounds and terpenes. Objective: this study set out to analyse the phytochemical composition and compare the antioxidant, anti-inflammatory and antibacterial activities of four Algerian medicinal plants: Mentha pulegium, Marrubium vulgare, Rosmarinus officinalis and Thymus vulgaris. Methods: aerial components were extracted using water, methanol and chloroform. Total phenolic, flavonoid and condensed tannin levels were measured spectrophotometrically, and important metabolites were identified by HPLC-DAD. Antioxidant (DPPH, FRAP), anti-inflammatory (protein denaturation inhibition) and antibacterial (disc diffusion, Staphylococcus aureus and Escherichia coli) activity were studied. Results: thymol (28-48%) and carvacrol (7-15%) dominated T. vulgaris, carnosic acid (25-35%) dominated R. officinalis, pulegone (48-75%) dominated M. pulegium, and marrubiin (30-40%) dominated M. vulgare. The T. vulgaris aqueous extract displayed the strongest antioxidant activity (IC50 = 0.18 ± 0.02 mg/mL) and 99.98% reduction of protein denaturation at 1 mg/mL, exceeding diclofenac sodium. Chloroform extracts displayed particular bactericidal activity. Strong connection was discovered between total phenolic content and antioxidant (r = -0.86) and anti-inflammatory (r = 0.79) activity. Conclusions: The present results suggest the pharmacological value of these Algerian Lamiaceae, and T. vulgaris emerged as the most promising candidate for pharmaceutical development, notably for antioxidant and antiinflammatory application.