A promising approach to enhance the total phenolic content and antioxidant activity of raw and processed jatropha curcas L. kernel meal extracts

Jatropha curcas a member of the Euphorbiaceae family is a drought resistant small tree of great economic importance in developing countries because of its several industrial and medicinal values. The antioxidative properties, total phenolic content and DNA protection potential of raw and processed kernel meal extracts of Jatropha were analyzed. The samples were extracted with 70% acetone and used for the evaluation of its antioxidant potential. The total phenolic content of raw and processed Jatropha kernel meal samples ranged between 9.06 and 22.22 mg TAN/g extract. The results of the study revealed that autoclaving and dry heat treatment causes a significant (P < 0.05) increases in the total phenolic content and antioxidant properties. Nevertheless, raw samples exhibited a high metal chelating activity (0.97 mg EDTA/g extract) compared to the processed samples. However, autoclaving with NaHCO3 and ash solution recorded the highest phenolic content (22.22 mg TAN/g extract), FRAP (2861.11 mmoL Fe(II)/g extract), phosphomolybdenum (353.61 mu moL ascorbic acid/g extract), DPPH (6.29g extract/g DPPH), nitric oxide (55%), superoxide (67%) and hydroxyl radical (49%) scavenging activity when compared to the raw and other processed samples. The present studies may be of importance in varietal improvement, nutraceuticals and bio-pharmaceuticals as possible sources of cost-effective natural antioxidants. (C) 2012 Elsevier B.V. All rights reserved.