Antioxidant activity of five vegetables traditionally consumed by south-Asian migrants in Bradford, Yorkshire, UK

Five vegetables traditionally consumed among South‐Asian migrants in Bradford (Yorkshire, UK) were tested for their free radical scavenging activity (FRSA) in the DPPH (1,1‐diphenyl‐2‐picrylhydrazil radical) screening assay (using extracts prepared both by cold maceration and also by boiling the plant in the solvent under reflux) and for their in vitro non‐enzymatic inhibition of bovine brain lipid peroxidation. In both antioxidant assays a strong activity was shown by extracts derived from okra (Abelmoschus esculentus, Malvaceae) fruits and charungli (Caralluma edulis, Asclepiadaceae) aerial parts. Extracts from bitter melon (Momordica charantia, Cucurbitaceae) and angular loofah (Luffa acutangula) showed a significant difference in the FRSA between the extract obtained by using cold maceration and that prepared by boiling the plant in the solvent under reflux, suggesting the chemical composition of the plant changed during the heating process, leading to an increase in the amount of antioxidant components. These findings confirm the great interest of the nutraceutical sciences in extracts of Caralluma edulis, whose phytochemistry and phytopharmacology should be investigated further in order to detect possible phytotherapeutic uses in the prevention of ageing related diseases (ARDs) and Alzheimer disease (AD). Copyright © 2005 John Wiley & Sons, Ltd.