Title: Re: NO2 (Nitric Oxide)
Post by floridian on Jan 25th, 2005, 1:08pm
on 01/25/05 at 12:14:53, maureen wrote:Does the green tea help very much sounds like something worth trying? |
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Dunno exactly as I am typically using several things - if I had to name the one thing I thought was most effective, it would be melatonin. But green tea, (and oolong and pu-ehr which also have catechins), and turmeric/curcumin do affect the nitric oxide pathways - either turning down production, or minimizing the negative effects from NO formed nitrite, nitration reactions, etc.
Quote:J Agric Food Chem. 2004 Dec 29;52(26):8169-76.
Effects of pu-erh tea on oxidative damage and nitric oxide scavenging.
Duh PD, Yen GC, Yen WJ, Wang BS, Chang LW.
Department of Food Science and Technology, Chia Nan University of Pharmacy and Science, 60 Erh-Jen Road, Section 1, Pao-An, Jen-te Hsiang, Tainan Hsien, Taiwan. ipdduh@mail.chna.edu.tw
The effects of pu-erh tea, which is prepared by fermentation of tea, on oxidative damage and nitric oxide scavenging, compared with various other brands of tea were investigated. The total antioxidant activity was determined using the Trolox equivalent antioxidant capacity (TEAC) assay. The results showed that TEAC values of the 200 microg/mL water extracts of pu-erh tea (WEPT), green tea, oolong tea, and black tea were 86.3, 85.3, 87.4, and 80.3 (microg/mL), respectively, indicating that WEPT showed a significant antioxidant activity. WEPT, like green tea extract, oolong tea extract, and black tea extract, exhibited a remarkable protective effect in lipid (liposome) and nonlipid (protein and deoxyribose) model systems, implying that it is an inhibitor of lipid and nonlipid oxidative damage. It also exhibited metal-binding ability, reducing power, and scavenging effect for free radicals. Moreover, WEPT showed a decreasing effect on nitric oxide production of lipopolysaccharide-induced RAW 264.7 macrophages. In addition, the results revealed that epicatechin (EC), flavonoid, ascorbic acid, and polyphenolic compounds are present in WEPT, which may partially account for the protective effect on oxidative damage. Thus, WEPT may have potential as an antioxidant and as a nitric oxide scavenging agent.
Kim MJ, Ryu GR, Kang JH, Sim SS, Min do S, Rhie DJ, Yoon SH, Hahn SJ, Jeong IK, Hong KJ, Kim MS, Jo YH. Inhibitory effects of epicatechin on interleukin-1beta-induced inducible nitric oxide synthase expression in RINm5F cells and rat pancreatic islets by down-regulation of NF-kappaB activation. Biochem Pharmacol. 2004 Nov 1;68(9):1775-85.
Chen JH, Tipoe GL, Liong EC, So HS, Leung KM, Tom WM, Fung PC, Nanji AA. Green tea polyphenols prevent toxin-induced hepatotoxicity in mice by down-regulating inducible nitric oxide-derived prooxidants. Am J Clin Nutr. 2004 Sep;80(3):742-51.
Biochem Pharmacol. 2004 Apr 1;67(7):1285-95.
Interference of the polyphenol epicatechin with the biological chemistry of nitric oxide- and peroxynitrite-mediated reactions.
Wippel R, Rehn M, Gorren AC, Schmidt K, Mayer B. Institut fur Pharmakologie and Toxikologie, Karl-Franzens Universitat Graz, Universitatsplatz 2, A-8010 Graz, Austria.
The formation of reactive nitrogen species in mammalians has both beneficial and undesirable effects. Nitric oxide (NO) production in endothelial cells leads to vascular smooth muscle relaxation, but if reactive nitrogen species are generated in high amounts by cells under inflammatory conditions they are toxic. Flavonoids like (-)-epicatechin show an inverse association of their intake with diseases thought to be associated with overproduction of reactive nitrogen species. We found that the formation of cyclic GMP in cultured porcine aortic endothelial cells was not affected by up to 1 mM (-)-epicatechin. Half maximal inhibition of interferon-gamma/lipopolysaccharide induced nitrite accumulation in murine macrophages required about 0.5 mM of the flavonoid. In contrast, nitration of free tyrosine triggered by 0.1 and 1 mM authentic peroxynitrite was inhibited by (-)-epicatechin with IC(50) values of 6.6 and 28.0 microM, respectively. The presence of 15 mM sodium bicarbonate had no significant effect. Nitration of protein-bound tyrosine in phorbol 12-myristate 13-acetate treated HL-60 cells in the presence of nitrite was inhibited by (-)-epicatechin at a similar concentration range (IC(50)=10-100 microM). Myeloperoxidase activity of phorbol 12-myristate 13-acetate stimulated HL-60 cells was inhibited by (-)-epicatechin with an IC(50) value of 77.4 microM. Epicatechin inhibited dihydrorhodamine oxidation by 50 microM authentic peroxynitrite and 1 mM 3-morpholino-sydnonimine with IC(50) values of 11.8 and 0.63 microM, respectively. Our data suggest that at up to 0.1 mM (-)-epicatechin preferentially inhibits NO-related nitration and oxidation reactions without affecting NO synthesis and cyclic GMP signaling. |
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