title: A rapid screening assay for antioxidant potential of natural and synthetic agents in vitro.
abstract: There are literally thousands of known agents with potential chemopreventive and antioxidant activity; however, the expanding list of natural and synthetic compounds makes it difficult to test every agent in the widely accepted 2-year animal bioassay and human clinical trials. Therefore, short-term screening assays are needed to sort out the most efficacious compounds for long-term animal studies. In the present study, the identification of chemopreventive agents with efficacious antioxidant potential was explored with a Cu2+-mediated Fenton-type reaction, coupled with oxidative DNA lesion detection by 32P-postlabeling. Several agents inhibited the formation of 8-oxo-2'-deoxyguanosine (8-oxodG), a benchmark oxidative DNA lesion, but ellagic acid, a polyphenol found in berries, offered maximal (>80%) inhibition of 8-oxodG formation. However, a well-known tea polyphenol, epigallocatechin gallate, along with silymarin and D,L-sulforaphane, exhibited a pro-oxidant effect, with 50-70% increase in 8-oxodG induction. In general, our results agree with the reported antioxidant - pro-oxidant activities of the compounds, rendering this in vitro screening assay to be useful in determining the antioxidant potential of compounds rapidly and cost-effectively.
authors.affiliation: Department of Preventive Medicine and Environmental Health, University of Kentucky Medical Center, Lexington 40536-0305, USA.
authors.forename: Praveen
authors.initials: P
authors.lastname: Srinivasan
authors.forename: Manicka V
authors.initials: MV
authors.lastname: Vadhanam
authors.forename: Jamal M
authors.initials: JM
authors.lastname: Arif
authors.forename: Ramesh C
authors.initials: RC
authors.lastname: Gupta
mesh_terms: D000080242:8-Hydroxy-2'-Deoxyguanosine; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D000975:Antioxidants / Q000494:pharmacology*; D001681:Biological Assay; D002392:Catechin / Q000031:analogs & derivatives / Q000494:pharmacology; D003300:Copper / Q000494:pharmacology*; D004249:DNA Damage; D003849:Deoxyguanosine / Q000031:analogs & derivatives / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004354:Drug Screening Assays, Antitumor / Q000379:methods*; D004610:Ellagic Acid / Q000494:pharmacology; D016166:Free Radical Scavengers / Q000494:pharmacology*; D006801:Humans; D010100:Oxygen / Q000378:metabolism; D017382:Reactive Oxygen Species
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D000975:Antioxidants; D016166:Free Radical Scavengers; D017382:Reactive Oxygen Species; D004610:Ellagic Acid; D003300:Copper; D000080242:8-Hydroxy-2'-Deoxyguanosine; D002392:Catechin; C045651:epigallocatechin gallate; D003849:Deoxyguanosine; D010100:Oxygen