Effects of temperature and storage on the antioxidant potential, polyphenols and Vitamin-C contents of azadirachta indica leave aqueous extract

Abstract

The aim of the study was to investigate the effects of effects of storage and temperature on the antioxidant potential, vitamin-C contents, total as well as selected individual phenolic acids and flavonoids of fresh aqueous leaves extract of Azadirachta Indica. The antioxidant activity of Azadirachta Indica leaves aqueous extract was determined by scavenging of DPPH free radical, while the phenolic compounds and vitamin-C contents by HPLC method. The analyses were carried out on crude extract of fresh leaves and after storage time of 1, 2 and 3 month at temperature of 20, 30 and 50o C. Storage for longer duration and rise in temperature caused decreasing the phenolic acids and vitamin C contents as well as antioxidant potential. Vitamin C contents were decreased up to 91% upon storage for 3 months at 50o C, while the anti-oxidant potential was decreased 29 %. The effect of storage time and temperature on individual phenolic acid and flavonoids were also remarkable, except ferulic acid which increased upon storage and rise in temperature.