Reference

Flavone modulators of rat hepatic aryl hydrocarbon hydroxylase

Flavone modulators of rat hepatic aryl hydrocarbon hydroxylase. Friedman, Fred K.; West, Donna; Sugimura, Takashi; Gelboin, Harry V. (Lab. Mol. Carcinog., Natl. Cancer Inst., Bethesda, MD 20205, USA). Pharmacology, 31(4), 203-7 (English) 1985. CODEN: PHMGBN. ISSN: 0031-7012. DOCUMENT TYPE: Journal CA Section: 4 (Toxicology) A series of 18 flavone modulators of aryl hydrocarbon hydroxylase (AHH) [9037-52-9] were employed to distinguish and probe for different cytochrome P 450 [9035-51-2] isozymes in liver microsomes from control and 3-methylcholanthrene (MC)-injected rats. Some flavones [maackiain acetate (I) [2035-16-7], flavanone [487-26-3], mollisacacidin [967-27-1], embinin [52589-13-6], sciadopitysin [521-34-6]] activated, whereas most of the tested compds. inhibited the MC-induced type of AHH. Although all flavones either inhibited or had little effect on the constitutive AHH in microsomes from control rats, the degree of inhibition varied greatly: some flavones (chrysin [480-40-0], chrysoeriol [491-71-4], baicalein [491-67-8], I, isoliquiritigenin [961-29-5], sciadopitysin) inhibited >75% of the AHH. The various flavones screened may prove useful in defining the cytochrome P 450 content of tissues and for probing the active sites of individual isozymes. The modulatory effects of the naturally occurring flavones assume addnl. importance in that they may be factors in animal and human responsiveness to cytochrome P 450 substrates.

12-O-tetradecanoylphorbol 13-acetate-caused increase in vascular permeability in mouse skin (II)

12-O-tetradecanoylphorbol 13-acetate-caused increase in vascular permeability in mouse skin (II). Effects of caffeic acid derivatives, chalcone derivatives and calcium blockers on it. Nakadate, Teruo; Yamamoto, Satoshi; Aizu, Eriko; Kato, Ryuichi (Sch. Med., Keio Univ., Tokyo, Japan). Ensho, 4(4), 554-6 (Japanese) 1984. CODEN: ENSHEE. ISSN: 0389-4290. DOCUMENT TYPE: Journal CA Section: 4 (Toxicology) 3,4,2',4'-Tetrahydroxychalcone [21849-70-7], 3,4,2'-trihydroxychalcone [6272-43-1], isoliquiritigenin [961-29-5], 3,4-dihydroxychalcone [72704-76-8], Ca blockers (nifedipine [21829-25-4], verapamil [52-53-9], D 600 [16662-47-8]) and quercetin [117-39-5] inhibited TPA (I) [16561-29-8]-induced vascular permeability in mice, whereas caffeic acid [331-39-5] and chlorogenic acid [327-97-9] did not. Chalcone derivs. with the catechol group inhibited both lipoxygenase [9029-60-1] and cyclooxygenase [39391-18-9] in the skin whereas those without the catechol group inhibited cyclooxygenase but not lipoxygenase. Caffeic acid derivs. had no effect on both enzymes. Quercetin inhibited lipoxygenase but not cyclooxygenase.