title: Screening of potential chemopreventive compounds from Poncirus trifoliata Raf.
abstract: Chemopreventive agents induce a battery of genes whose protein products can protect cells from chemical-induced carcinogenesis. In this study, we isolated three different coumarins compounds (1; poncimarin, 2; heraclenol 3'-methyl ester and 3; oxypeucedanin methanolate) from Poncirus trifoliata Raf., and studied whether these compounds increase glutathione S-transferase (GST) expression and activity in the H4IIE cell-line (a rat hepatocyte cell line). CDNB (1-chloro-2,4-dinitrobenzene; GST subtype-nonspecific) and NBD (7-chloro-4-nitrobenzo-2-oxa-1,3-diazole; GSTalpha-type-specific) assays revealed that compound 1 most potently increased GST enzyme activities. Western blot analysis using subtype-specific antibodies confirmed that these three coumarins also selectively increased GSTalpha-protein expression, and that compound 1 most actively induced GSTalpha. In contrast, the expressions of the GSTmu and GSTmu subtypes were not altered by these three coumarins. Reporter gene analysis using an antioxidant response element (ARE) containing construct and subcellular fractionation assays, revealed that GSTalpha-induction by compound 1 might be associated with Nrf2/ARE activation. These results suggest that these three coumarin compounds from Poncirus trifoliata Raf possess phase II enzyme inducible functions, and in particular, that poncimarin has chemopreventive potential.
authors.affiliation: College of Pharmacy, Chosun University, Gwangju, South Korea.
authors.forename: Yuba Raj
authors.initials: YR
authors.lastname: Pokharel
authors.forename: Ji-Eun
authors.initials: JE
authors.lastname: Jeong
authors.forename: Soo Jin
authors.initials: SJ
authors.lastname: Oh
authors.forename: Sang Kyum
authors.initials: SK
authors.lastname: Kim
authors.forename: Eun-Rhan
authors.initials: ER
authors.lastname: Woo
authors.forename: Keon Wook
authors.initials: KW
authors.lastname: Kang
mesh_terms: D000818:Animals; D016588:Anticarcinogenic Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D000975:Antioxidants / Q000378:metabolism; D015153:Blotting, Western; D002273:Carcinogens / Q000633:toxicity; D045744:Cell Line, Tumor; D003374:Coumarins / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D004354:Drug Screening Assays, Antitumor; D005638:Fruit / Q000737:chemistry; D005978:Glutathione / Q000378:metabolism; D022781:Hepatocytes / Q000187:drug effects / Q000378:metabolism; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D051267:NF-E2-Related Factor 2 / Q000378:metabolism; D032104:Poncirus / Q000737:chemistry*; D051381:Rats; D020218:Response Elements; D013055:Spectrophotometry, Infrared; D013056:Spectrophotometry, Ultraviolet; D014178:Translocation, Genetic / Q000187:drug effects
chemical_list: D016588:Anticarcinogenic Agents; D000975:Antioxidants; D002273:Carcinogens; D003374:Coumarins; D051267:NF-E2-Related Factor 2; D008156:Luciferases; D005978:Glutathione