In vitro antioxidant and metal chelating properties of corm, tepal and leaf from saffron (Crocus sativus L.)

Corms, tepals and leaves of saffron are by-products generated during the processing of the stigmas of the flower (saffron spice). To increase the overall profitability of this crop, these by-products have been investigated as a potential source of antioxidant compounds. With this purpose, several in vitro antioxidant methods, such as the beta-carotene/linoleate model system, reducing power, DPPH and nitric oxide radical scavenging, and iron and copper ion chelation have been assayed on corm, tepal and leaf extracts. Best antioxidant properties were observed for leaf extract, which totally inhibited the oxidation of beta-carotene at 10 mu g/mL and showed a DPPH scavenger activity up to 32 times higher than those reported for traditional sources of antioxidants like grapes and berries. Tepal extract showed an extensive inhibition of beta-carotene oxidation, and significant scavenging NO radical and Cu2+-chelating activities. In contrast, corm extract was a poor antioxidant although showed a slight Cu2+-chelating activity. It can be concluded that tepals and especially leaves of saffron constitute an exploitable source of antioxidant and metal chelating compounds. (C) 2012 Elsevier B.V. All rights reserved.