Influence of solvent on flavonoid, polyphenol content, antioxidant capacity and nitric oxide inhibition of Centella asiatica extracts

Abstract

This study investigated the influence of solvents on the total polyphenol and flavonoid content; antioxidant  and anti-inflammatory activity (NO inhibition) of Centella asiatica extracts. Food-grade ethanol 90° (ethanol) and ethanol/water mixtures at ratios of 7: 3, 5: 5, and 3: 7 were used as the extracting solvents, yielding the corresponding extracts CA-E100, CA-EW73, CA-EW55 and CA-EW37, respectively. The results showed that the CA-EW73 extract had the highest total polyphenol content of 112.29 mg QE/g, while the CA-E100 extract had the highest total flavonoid content of 55.51 mg GAE/g. The CA-EW73 extract also exhibited the best antioxidant  activity as determined by the phosphomolybdenum and DPPH methods and the best ability to inhibit nitric oxide production with EC₅₀ values of the assays were 67.03, 63.98 and 50.29 µg/mL, respectively. These results facilitate selecting suitable solvent in developing natural antioxidant and natural NO inhibitory products derived from Centella asiatica.