Evaluation of the antioxidant activity of non-transformed and transformed pineapple: A comparative study

Pineapple has several beneficial properties including antioxidant activity. We investigated the antioxidant effect of different extracts of non-transformed (S) and transformed pineapple (with the magainin gene construct, [TS], for disease resistance). They were examined using 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging, oxygen radical absorbance capacity (ORAC) and lipid peroxidation assays besides phenolic and flavonoid contents. HPLC analysis was carried out to identify the possible components responsible for the differences observed. The present study indicates that the ORAC values of extracts range from 9.5 to 26.4, similar to or higher than those for some fruits and vegetables. The HPLC analysis shows that the main compounds present are ascorbic acid, quercetin, flavone-3-ols, flavones, cinnamic acids. The TS core Et. extract exhibited slightly higher concentration of ascorbic acid and considerably higher concentration of flavon-3-ols. Our study, in general, indicates that the transformation event has caused only marginal difference in antioxidant activity. Moreover the TS samples showed more antioxidant activity in some aspects and also exhibit more flavonoid content. It appears that plant cell transformation has only caused minor and favourable changes in the overall chemical composition. Thus the TS pineapple variety may have potential applications in human health like its non-transformed counterpart. (C) 2009 Elsevier Ltd. All rights reserved.