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

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 50°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 50°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.

Development of HPLC method by UV-VIS detection for the quantification of phenolic acids in different Ocimum sanctum Linn. extracts.

A simple and rapid chromatographic method has been developed for the simultaneous determination of five phenolic acids including Gallic acid, Chloroganic acid, Syringic acid, Benzoic acid and Vanillic acid by HPLC with UV-VIS detector. These Phenolic acids were separated by analytical column Intersil ODS-3 C18, a gradient elution system of ACN and acidified water solution with 1ml/min flow rate and quantified in a total run of 30 minutes at 210nm wavelength. In the quantitative analysis of these compounds showed good regression (0.995-0.999). The limit of detection [LOD] and limit of quantification [LOQ] of these compounds were in the range of 0.15-0.46 and 0.42-2.47 ßg/mL. The average recoveries were between 95.8-103.1% and their RSD values were less than 3.34%. By the proposed method Gallic acid, Chloroganic acid and Syringic acid were found and quantified in Methanolic, Ethanolic and Acetonic extract of Ocimum sanctum Linn. leaves. While the two other phenolic acids benzoic acid and vanillic acid was not found in the extracts of Ocimum sanctum Linn. leaves.