Evaluation of polyphenol composition and biological activities of two samples from summer and winter seasons of Ligularia fischeri var. Spiciformis Nakai

Abstract

Phenolic contents, antioxidant and antimicrobial activities were determined by two samples from summer (June) and winter (December) seasons of Ligularia fischeri var. spiciformis Nakai. A total of 24 phenolic compounds were identified by ultra-performance liquid chromatography (UPLC) analysis. Myricetin (1964.35 and 1829.12 μg/g) was the most dominant flavonol compared to quercetin and kaempferol. Salicylic acid (222.80 and 215.25 μg/g) was the most important phenolic compound compared to pyrogallol, caffeic acid, gentisic acid, o-coumaric acid, gallic acid, protocatechuic acid and ferulic acid in summer (June) and winter (December) seasons. Phenolic contents and antioxidant capacities were estimated for the various solvent extracts (petroleum ether, butanol, ethyl acetate, methanol and water). Ethyl acetate extract exhibited the highest phenolic (332.64 and 299.44 mg/g gallic acid equivalent) and flavonoid contents (5.72 and 5.29 mg/g quercetin equivalent) and also the strongest antioxidant activity in summer and winter seasons. Due to these metabolic variations, the antioxidant and antimicrobial activities were increased with summer seasons compared to winter seasons. Our study shows that the samples collected in June had higher phenolic compounds, stronger antioxidative and antimicrobial activity than the samples of L. fischeri leaf extracts collected in December.

Keywords: Biological activities; Ligularia fischeri; flavonoids; phenolic compounds; seasonal variations.