Altitudinal variation of berberine, total phenolics and flavonoid content in Thalictrum foliolosum and their correlation with antimicrobial and antioxidant activities

Abstract

Background: The quality of herbal medicine is determined by its secondary metabolites, which may vary according to growth, season and altitude etc. Objective: We studied the variation in phytochemistry and biological activities of Thalictrum foliolosum (TF) roots collected from four sites at different altitudes. Material and methods: The berberine content in different extracts of T. foliolosum roots collected from various altitudes was estimated using HPTLC. Total phenolic and flavonoid contents were determined using Folin-Ciocalteau reagent and aluminum chloride method respectively. The sensitivity of microbes for the extracts was studied using disc diffusion and the MIC was estimated using broth dilution method. Antioxidant capacity of the plant was studied using β-carotene bleaching assay, lipid peroxidation assay using goat liver, reducing power assay and DPPH free radical scavenging activity. Results: Berberine content varied inversely with altitude; while phenol and flavonoid content of TF increased at higher altitudes. All the TF extracts showed moderate to high activity against Candida albicans, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. Extracts with high berberine content were most effective against C. albicans and S. aureus and also showed relatively significant anti-lipid peroxidation, β-carotene bleaching and reducing power. TF extracts with higher phenol and flavonoid content showed better scavenging of DPPH free radicals. Berberine was used as a standard in all the antioxidant and antimicrobial experiments performed. Conclusion: Thalictrum from lower elevations can be explored as an alternate source of berberine and the plant has high antioxidant and antimicrobial properties owing to its berberine content. Keywords: Altitudinal variation, Antimicrobial, Antioxidant, Berberine, Flavonoid, HPTLC, Phenolics, Thalictrum foliolosum