Antioxidant, antimicrobial and phytochemical analysis of Microtoena patchoulii leaves: A rare plant species from North East India

Microtoena patchoulii [(C.B. Clarke ex J.D. Hooker) C.Y. Wu et Hsuan] is a lesser-known plant of family Lamiaceae found in Asia traditionally used for medicinal and cosmetic purposes. The present study focuses on the phytochemical constituents, antioxidant properties and antimicrobial activity of the hexane and methanolic extract of M. patchoulii leaves collected from Manipur, Northeast India. Phytochemical screening was conducted on both hexane and methanolic extracts to detect the presence of phenols and flavonoids. Radical scavenging and reducing power were estimated by quantitative antioxidant assays, such as 2,2-diphenyl-1-picrylhydrazyl (DPPH), [2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid)] (ABTS) and ferric reducing antioxidant power (FRAP). GC-MS analysis was performed on the methanolic extract to identify bioactive constituents. Antimicrobial activity was assessed against selected bacterial and fungal strains using standard methods. Phytochemical analysis of the methanolic extracts of the leaves confirmed the presence of phenols and flavonoids. GC-MS analysis of the methanolic and hexane extracts identified key bioactive compounds, including n-Hexadecanoic acid, 1,3-Benzodioxole and various terpenoids and phenolics. Some of these compounds are reported to exhibit antioxidant, antimicrobial and anti-inflammatory properties. The methanolic extract of leaves exhibited high antioxidant activity with an FRAP value of 2.89 ± 0.03 mM FeSO₄ equivalent/mL. ABTS IC₅₀ of 15.12 µg/mL and DPPH IC₅₀ of 433.78 µg/mL. Antibacterial studies using methanolic extract revealed selective activity against Escherichia coli. There were significant antifungal effects against Saccharomyces cerevisiae and Candida tropicalis. However, no inhibition effect was observed against the bacteria Staphylococcus aureus. The study supports the therapeutic potential of M. patchoulii for its antioxidant and antifungal efficacy. The GC-MS analysis identified several compounds with reported antimicrobial and antioxidant properties, supporting the observed bioactivities. These findings support the plant’s traditional use and highlight its potential for drug development.