Phytochemical characterization, antioxidant, and antimicrobial activities of the Ayurvedic polyherbal formulation Mentone

Abstract

Introduction: Polyherbalism is extensively practiced in traditional medicine and constitutes complementary and alternative medicine (CAM). Greater therapeutic efficacy ensues from the synergistic effects of constituents mediated by pharmacodynamic and pharmacokinetic interactions and safety at higher dosages. Very few studies exist on mechanistics, despite rampant polyherbal use. Mentone tablet is a polyherbal constituting equal components of Centella asiatica (L.) Urban, Convolvulus pluricaulis Choisy, Glycyrrhiza glabra L., and Tinospora cordifolia (Willd.) Miers ex Hook. F. and Thomson. Materials and Methods: Proximate and phytochemical analysis followed by quantification of polyphenolics was carried out. Asiatic acid, berberine, betaine, and glycyrrhizin were characterized using ultraviolet–high-performance liquid chromatography (UV-HPLC). Antioxidant activity was determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) quenching activity, ferric reducing ability of plasma (FRAP) assay, and hydrogen peroxide (H2O2) scavenging activity. Antimicrobial activity was determined by Kirby–Bauer disc diffusion microbial susceptibility test followed by minimum inhibitory concentration (MIC) method. Results: Aqueous extraction using Soxhlet generated maximum yield. Proximate analysis yielded 52.96% ash, pH ranged from 5.75 to 5.76, and 5% moisture content. Qualitative analysis revealed the presence of inorganic substances and phytochemicals: saponins, reducing sugars, terpenoids, starch, glycosides, and triterpenoids. Phenols were higher in aqueous, while flavonoids and tannins were higher in ethanolic extracts. HPLC revealed the presence of glycyrrhizin and asiatic acid. Mentone extracts at 100 µg/mL showed the highest antioxidant activity in DPPH, FRAP assays, and H2O2 radical scavenging. Ethanolic extracts above 50 mg/mL demonstrated antimicrobial activity against Staphylococcus aureus ATCC 25923 and Klebsiella pneumoniae ATCC 700603. Conclusion: Mentone contains phytochemicals with antioxidant and antimicrobial activities. With active constituents such as asiatic acid and glycyrrhizin, Mentone could constitute a CAM for oxidative stress-induced diseases, including neurodegeneration.