Solvent Polarity and Its Influence on Bioactive Compound Extraction from Himalayan Medicinal Plants

Abstract

Background: The Indian Himalayan Region (IHR) harbors a rich diversity of medicinal plants traditionally used for therapeutic purposes. However, the effectiveness of bioactive compound extraction depends largely on the polarity of the solvent employed. Optimizing solvent polarity can significantly enhance phytochemical yield and bioactivity, yet comparative studies across different Himalayan medicinal species remain limited.

Objectives: To evaluate the influence of solvent polarity on the extraction efficiency, phytochemical content, antioxidant potential, and antimicrobial activity of three Himalayan medicinal plants: Berberis aristata, Rheum emodi, and Nardostachys jatamansi.

Methods: Dried plant materials were subjected to successive solvent extraction using four solvents of increasing polarity: hexane, ethyl acetate, ethanol, and distilled water. Extracts were analyzed for extraction yield, qualitative phytochemical screening, total phenolic content (TPC), total flavonoid content (TFC), DPPH radical scavenging activity, and antimicrobial efficacy using standard protocols. All data were statistically analyzed using ANOVA.

Results: Ethanol and ethyl acetate extracts showed the highest extraction yields and superior TPC and TFC values compared to hexane and aqueous extracts. Antioxidant activity (IC₅₀: 38–43 µg/mL) and antimicrobial activity (zone of inhibition: up to 22 mm) were significantly higher in ethanol and ethyl acetate fractions. Hexane extracts exhibited minimal activity.

Conclusion: Solvent polarity markedly influences the efficiency of phytochemical extraction and associated bioactivity. Ethanol and ethyl acetate emerged as the most effective solvents for extracting antioxidant and antimicrobial compounds. These findings provide a scientific basis for solvent-specific extraction protocols in phytopharmaceutical development.