Basic Research
Copyright ©2005 Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Dec 28, 2005; 11(48): 7607-7614
Published online Dec 28, 2005. doi: 10.3748/wjg.v11.i48.7607
Protective effects of Asian green vegetables against oxidant induced cytotoxicity
Peter Rose, Choon Nam Ong, Matt Whiteman
Peter Rose, Matt Whiteman, Department of Biochemistry, Faculty of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, 8 Medical Drive, Singapore 117597, Singapore
Choon Nam Ong, Department of Community, Occupational and Family Medicine, Faculty of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, 8 Medical Drive, Singapore 117597, Singapore
Author contributions: All authors contributed equally to the work.
Correspondence to: Dr Peter Rose, Department of Biochemistry, National University of Singapore, 8 Medical Drive, 117597 Singapore. bchpcr@nus.edu.sg
Telephone: +65-6874-4996
Received: September 2, 2004
Revised: January 28, 2005
Accepted: February 1, 2005
Published online: December 28, 2005
Abstract

AIM: To evaluate the antioxidant and phase II detoxification enzyme inducing ability of green leaf vegetables consumed in Asia.

METHODS: The antioxidant properties of six commonly consumed Asian vegetables were determined using the ABTS, DPPH, deoxyribose, PR bleaching and iron- ascorbate induced lipid peroxidation assay. Induce of phase II detoxification enzymes was also determined for each respective vegetable extract. Protection against authentic ONOO- and HOCl mediated cytotoxicity in human colon HCT116 cells was determined using the MTT 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrasodium bromide) viability assay.

RESULTS: All of the extracts derived from green leaf vegetables exhibited antioxidant properties, while also having cytoprotective effects against ONOO- and HOCl mediated cytotoxicity. In addition, evaluation of the phase II enzyme inducing ability of each extract, as assessed by quinone reductase and glutathione-S-transferase activities, showed significant variation between the vegetables analyzed.

CONCLUSION: Green leaf vegetables are potential sources of antioxidants and phase II detoxification enzyme inducers in the Asian diet. It is likely that consumption of such vegetables is a major source of beneficial phytochemical constituents that may protect against colonic damage.

Keywords: Cruciferous vegetables; Lipid peroxidation; Free radicals; Isothiocyanates