Comparative phenolic content and antioxidant activity of some medicinal plant extracts prepared by choline chloride based green solvents and methanol

Abstract

In the present study, three north-western Himalayan medicinal plants, Ocimum sanctum, Terminalia bellerica and Terminalia chebula were used to evaluate the effectiveness of choline chloride based natural deep eutectic solvents (NADESs) in extracting the polyphenolic compounds. The natural deep eutectic solvents used in the study were choline chloride:glucose: water, choline chloride:fructose:water, choline chloride: xylose: water, choline chloride:glycerol:water and choline chloride:malic acid:water.The results of the above study showed that all the eutectic solvents were more effective in extracting phenolic compounds than methanol, however, choline chloride:malic acid:water based NADES was most effective among all the NADESs tested and methanol. Additionally, profiling of phenolic compounds in extracts obtained by choline chloride:malic acid:water and methanol was also carried out using HPLC analysis. It was also observed that extracts possessing higher polyphenolic content showed higher DPPH radical scavenging activity, ferric reducing antioxidant power, reducing power and α-glucosidase inhibitory activity. Our results suggests that natural deep eutectic solvents offers efficient and safe alternative to methanol for extraction of phenolic compounds from medicinal plants.

Keywords

• NADESs
• HPLC
• Choline chloride
• Malic acid
• Antioxidant activity
• α-glucosidase inhibitory activity