Effect of flavonoids

MIDDLETON E J and KANDASHWAMi c (1992) Effects of flavonoids on immune and inflammatory cell function. Biochemical Pharmacology 43, 1167-79. 

HAGIWARA M, INOUE s, TANAKA T, NUNOKI K, ITO M and HiDAKA H (1988) Differen-tial effects of flavonoids as inhibitors of tyrosine protein kinases and serine/threonine protein kinases Biochemical Pharmacology 37, 2987-92. 

Effects of flavonoids on aromatase activity, an in vitro study. JSteroid Biochem Mol Biol. 57 215-23. 

YOUNG J F, DRAGSTED L O, HARALDSDOTTIR J, DANESHVAR B, KALL M A, LOFT S, NILSSON L, NIELSEN S E, MAYER B, SKIBSTED L H, HUYNH-BA T, HERMETTER A and SANDSTROM B (2002) Green tea extract only affects markers of oxidative status postprandially lasting antioxidant effect of flavonoid-free diet, Brit J Nutr, 87, 343-55. 

LDL when oxidized is recognized to play a crucial role in the development of atherosclerosis. It was thought that flavonoids could also protect LDL against oxidation, especially by limiting the degradation of vitamin E, the main antioxidant in LDL. Other beneficial effects of flavonoids have been reported inhibition of platelet... 

R. Edenharder, 1. von Petersdorff, and R. Rauscher, Antimutagenic effects of flavonoids, chalcones and structurally related compounds on the activity of 2-amino-3-methylimidazo(4,5-f quinoline (IQ) and other heterocyclic amine mutagens from cooked food. Mutat Res. 287 261 (1993). 

The effect of flavonoids on spore germination and hyphal growth of ecto-mycorrhizal fungi is poorly known. However, several metabolites relea.sed by the plant roots trigger events leading to their infection (44,55). In the saprotrophic phase, spores of several ectomycorrhizal fungi respond to stimulation by abietic acid, the diterpene resin acid, in root exudates (56). 

There are several mechanisms involved in the vasodilator effect of flavonoids. The main mechanism seems to be related to the inhibition of protein kinase C or some of the processes activated by this protein. The inhibition of other protein kinases and cyclic nucleotide phosphodiesterase activity and blockage of calcium entry can also contribute to this effect to a greater or lesser extent (Alvarez Castro and Orallo, 2003 Herrera and others 1996). Certain flavonoids, like the flavonol myricetin, have a two-phase action on blood vessels vasoconstrictor in lowest active concentrations and vasodilator in higher concentrations (Alvarez Castro and Orallo, 2003). 

A significant protective effect of flavonoid consumption was observed on men, in the Finnish Mobile Clinic Health Examination Survey (Knekt and others 1996). In contrast, in a group of 35,000 men from the USA, coronary death was associated with high intakes of flavonoids in men with a previous history of coronary disease (Rimm and others 1996). 

The effects of flavonoids derived from soybean, cocoa, wine, and green tea on the reduction of risk for chronic cardiovascular diseases have been studied the most. 

Finally, it should also be considered that flavonoid-rich foods contain a great diversity of compounds with bioactive properties (for e.g., carotenoids, other phenolics, fiber, and minerals), and multiple interactions occur among all of them. There is also great diversity in the ingestion, absorption, and metabolism of these compounds in different populations, and all of these circumstances could camouflage any effect of flavonoids on disease prevention or treatment. 

Aviram M and Fuhrman B. 2003. Effects of flavonoids on the oxidation of LDL and atherosclerosis. In Rice-Evans C and Packer L, editors. Flavonoids in Health and Disease, 2nd ed. Boca Raton, FL CRC Press, pp. 165-203. 

Hamalainen M, Nieminen R, Vuorela P, Heinonen M and Moilanen E. 2007. Anti-inflammatory effects of flavonoids genistein, kaempferol, quercetin and daidzein inhibit STAT-1 and NF-kB activations whereas flavones, isorhamnetin, naringenins, and pelargonidin inhibit only NF-kB activation along with their inhibitory effect on iNOS expression and NO production in activated macrophagues. Mediators Inflamm 2007 45673. 

Herrera MD, Zarzuelo A, Jimenez J, Marhuenda E, Duarte J. 1996. Effects of flavonoids on rat aortic smooth muscle contractility structure-activity relationships. Gen Pharmacol 27 273-277. 

Takamatsu S, Galal AM, Ross SA, Ferreira D, ElSohly MA, Ibrahim ARS and El-Feraly FS. 2003. Antioxidant effect of flavonoids on DCF production in HL-60 cells. Phytother Res 17(8) 963—966. 

In addition to xanthine oxidase, flavonoids are able to inhibit the activity of a wide range of enzymes. These inhibitory effects of flavonoids may depend both on their free radical scavenging and chelating properties. Thus, it has been shown that flavonoids inhibit... 

The effects of flavonoids on in vitro and in vivo lipid peroxidation have been thoroughly studied [123]. Torel et al. [124] found that the inhibitory effects of flavonoids on autoxidation of linoleic acid increased in the order fustin < catechin < quercetin < rutin = luteolin < kaempferol < morin. Robak and Gryglewski [109] determined /50 values for the inhibition of ascorbate-stimulated lipid peroxidation of boiled rat liver microsomes. All the flavonoids studied were very effective inhibitors of lipid peroxidation in model system, with I50 values changing from 1.4 pmol l-1 for myricetin to 71.9 pmol I 1 for rutin. However, as seen below, these /50 values differed significantly from those determined in other in vitro systems. Terao et al. [125] described the protective effect of epicatechin, epicatechin gallate, and quercetin on lipid peroxidation of phospholipid bilayers. 

Numerous studies were dedicated to the effects of flavonoids on microsomal and mitochondrial lipid peroxidation. Kaempferol, quercetin, 7,8-dihydroxyflavone and D-catechin inhibited lipid peroxidation of light mitochondrial fraction from the rat liver initiated by the xanthine oxidase system [126]. Catechin, rutin, and naringin inhibited microsomal lipid peroxidation, xanthine oxidase activity, and DNA cleavage [127]. Myricetin inhibited ferric nitrilotriacetate-induced DNA oxidation and lipid peroxidation in primary rat hepatocyte cultures and activated DNA repair process [128]. 

The above findings are supported in the other studies of the inhibitory effects of flavonoids on iron-stimulated lipid peroxidation. Quercetin was found to be an inhibitor of iron-stimulated hepatic microsomal lipid peroxidation (/50 = 200 pmol I ) [134]. Flavonoids eriodictyol, luteolin, quercetin, and taxifolin inhibited ascorbate and ferrous ion-stimulated MDA formation and oxidative stress (measured by fluorescence of 2,7,-dichlorodihydro-fluorescein) in cultured retinal cells [135]. It should be mentioned that in recent work Heijnen et al. [136] revised the structure activity relationship for the protective effects of flavonoids against lipid peroxidation. 

It must be noted that the inhibitory effects of flavonoids and other antioxidants in nonhomogenous biological systems can depend not only on their reactivities in reactions with free radicals (the chain-breaking activities) but also on the interaction with biomembranes. Thus, Saija et al. [137] compared the antioxidant effects and the interaction with biomembranes of four flavonoids quercetin, hesperetin, naringen, and rutin in iron-induced... 

It is known that the toxic effects of some solid particles and fibers (latex, zeolite, asbestos fibers, etc.) depend on the stimulation of free radical production. Therefore, the inhibitory effects of flavonoids on particle-mediated damaging processes might be expected. Thus, rutin... 

Cytotoxic prooxidant effects of flavonoids can also be a consequence of their enzymatic oxidation. For example, it was found that quercetin was oxidized by lactate peroxide to form semiquinone and quinone [181]. 

Because of the advantageous dietary effects of flavonoids they have been vigorously investigated in food and food products. The objectives of these measurements were the separation and quantitation of well-known flavonoids in foods and the identification of new flavonoids. An HPLC-ESI MS method has been developed for the isolation and identification of new quercetin derivatives in the leaves of Eruca sativa (Mill). Fresh leaves (500g) were homogenized with 1 200 ml of methanol-water (7 3, v/v), the suspension was macerated for 24h at ambient temperature, then it was filtered, concentrated to 50 ml and diluted with water to 500 ml. The extract was applied to an Amberlite XAD-2 column (75 X 8cm i.d.) and was washed subsequently with 11 of water and 11 of diethyl ether. The glucoside fraction was eluted with 1.51 of methanol and the eluate was concentrated in vacuum and liophilized. 

Maruyama, H., Sumitou, Y., Sakamoto, T., Araki, Y. and Hara, H. (2009) Biol. Pharm. Bull., Antihypertensive effects of flavonoids isolated from Brazilian green propolis in spontaneously hypertensive rats, 32(7), 1244-1250. 

Horowitz RM (1986) Taste effects of flavonoids. In Cody V, Middleton E, Hatbome JB (eds) Plant flavonoids in biology and medicine. Alan R. Liss Inc, NewYork, NY, pp 163-176... 

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