Protective effects of Asian green vegetables against oxidant induced cytotoxicity.
OBJECTIVE
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.


CONCLUSIONS
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.
Rose
Peter
P
Department of Biochemistry, National University of Singapore, 8 Medical Drive, 117597 Singapore. bchpcr@nus.edu.sg
Ong
Choon Nam
CN
Whiteman
Matt
M
D027721:Amaranthus; D000975:Antioxidants / Q000494:pharmacology*; D001937:Brassica; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D004790:Enzyme Induction; D016166:Free Radical Scavengers / Q000494:pharmacology; D005978:Glutathione / Q000096:biosynthesis; D006801:Humans; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000096:biosynthesis; D010636:Phenols / Q000032:analysis; D010936:Plant Extracts / Q000494:pharmacology*; D014675:Vegetables
D000975:Antioxidants; D016166:Free Radical Scavengers; D010636:Phenols; D010936:Plant Extracts; D016660:NAD(P)H Dehydrogenase (Quinone); D005978:Glutathione