Flavonoid compounds

T.R. Seshadri, Interconversions of Flavonoid Compounds, in "The Chemistry of Flavonoid Compounds" T.A. Geissman, Ed. Pergamon Press p. 156, Oxford, (1962)... 

Fig. 2.10 Triketones, compounds 50-52, and flavonoids, compounds 53-56 from Leptospermum scoparium...

GRIFFITHS L A and BARROW A (1972) Metabolism of flavonoid compounds in germ-free rats. Biochem J12, 1161-2. 

ROBERTS E A H (1962) Economic importance of flavonoid substances Tea fermentation , in GeissmanT A, Chemistry of Flavonoid Compounds, Oxford, UK, Pergamon Press, 468-512. 

The mechanism of action proposed is based on a direct binding to the channel and the following partial block of the ATP-binding pocket of CFTR (French et al., 1997), a mechanism similar to that used by genistein to inhibit the activity of other ATP-utilizing enzymes such as protein kinases and topoisomerase II (Polkowski and Mazurek, 2000 and refs therein). The selection of flavonoid compounds or the development of synthetic drugs reasonably selective for CFTR activation might be an area for future clinical trials. 

S. Chabot, R. Bel-Rhlid, R. Chenevert, and Y. Piche. Hyphal growth promotion in vitro of the VA mycorrhizal fungus Gigaspora nuirgarila by the activity of structurally specific flavonoid compounds under CO enrichment conditions. New Phy-lol. /22-.461 (1992). 

Effects of Allelochemlcals on ATPases. Several flavonoid compounds inhibit ATPase activity that is associated with mineral absorption. Phloretin and quercetin (100 pM) inhibited the plasma membrane ATPase Isolated from oat roots (33). The naphthoquinone juglone was inhibitory also. However, neither ferulic acid nor salicylic acid inhibited the ATPase. Additional research has shown that even at 10 mM salicylic acid inhibits ATPase activity only 10-15% (49). This lack of activity by salicylic acid was substantiated with the plasma membrane ATPase Isolated from Neurospora crassa (50) however, the flavonols fisetln, morin, myricetin, quercetin, and rutin were inhibitory to the Neurospora ATPase. Flavonoids inhibited the transport ATPases of several animal systems also (51-53). Thus, it appears that flavonoids but not phenolic acids might affect mineral transport by inhibiting ATPase enzymes. 

Table 5.1. Typical flavonoid compounds in major subgroups of selected fruits and vegetables0... 

The antioxidant capacity retained in carrots washed with ASC could be attributed to retention of phenol and flavonoid compounds as well as carotene content (Ruiz-Cruz and others 2007). These results suggest that the use of sanitizers such as ASC is helpful in preserving the antioxidant capacity of carrots. Similar ORAC values were observed between different sanitizers and both water conditions, without significant changes. This is a clear example of a postharvest treatment maintaining the nutritional value of produce. 

Anthocyanins are ubiquitous in the plant kingdom. They are responsible for many of the orange, red, blue, violet, and magenta colors. They have been the object of intensive research from a taxonomic point of view and this has resulted in about 275 known structures and about 5,000 of the chemically closely related flavonoid compounds. Their use as colorants dates back to antiquity since the Romans used highly colored berries to augment the color of wine. 

The quantitative results are compiled in Table 2.6. For peak identification see Fig. 2.3. Storage experiments proved that the carotenoid composition of products did not change markedly in one year, the brownish colouration may be due to the oxidation of flavonoid compounds [27],... 

Yu O, Matsuno M, Subramanian S (2006) Flavonoid compounds in flowers genetics and biochemistry. In da Silva JAT (ed) Floriculture, ornamental and plant biotechnology, vol. 1. Global Sciences Book, London, pp 282-292... 

Based on the chemical structures of the isolated norlignans, several hypothetical biosynthetic pathways were proposed [16-18], All these proposed pathways involved coupling of two phenylpropanoid monomer units followed by a loss of one carbon atom to give rise to norlignans. Although this mechanism seemed plausible, another mechanism that involved the addition of two carbon atoms to flavonoid compounds (C6-C3-C6) to give norlignans (Ce-Cs-Ce) could not be mled out. 

Condensed or catechin tannins (catechol tannins. Fig. 11.3) are the most common tannins in vascular plants, occurring in three quarters of gym-nosperms and over half of the angiosperms. They are unbranched, linear polymers of flavonoid compounds (flavan-3-ols), linked through acid-labile carbon-carbon bonds. Condensed tannins may protect plant cell walls against microbial attack and so may affect microbial fermentation of plant cell walls in herbivores. 

A publication that nicely complements this review is Chang s account of pharmacophore-based in silico models [101] which, in addition to P-gp, is dedicated to the other two major efflux pumps MRPl and BCRP. Unfortunately the most recent nonpharmacophoric in silico modeling efforts around the latter transporters are solely based on flavonoid compounds, which limits the applicability of their conclusions [102, 103]. 

Various analytical methods exist for flavonoids. These range from TLC to CE. With the introduction of hyphenated HPLC techniques, the analytical potential has been dramatically extended. Gas chromatography (GC) is generally impractical, due to the low volatility of many flavonoid compounds and the necessity of preparing derivatives. However, Schmidt et al. ° have reported the separation of flavones, flavonols, flavanones, and chalcones (with frequent substitution by methyl groups) by GC. 

Miyake, Y. et al., Isolation of C-glucosylflavone from lemon peel and antioxidative activity of flavonoid compounds in lemon fruit, J. Agric. Food Ghem., 45, 4619, 1997. 

Kweon, M.H. et al.. Structural characterization of a flavonoid compound scavenging superoxide anion radical isolated from Capsella bursa-pastoris, J. Biochem. Mol Biol, 29, 423, 1996. 

Bramati, L. et al.. Quantitative characterization of flavonoid compounds in Rooibos tea (Aspa-lathus linearis) by LC-UV/DAD, J. Agric. Food Chem., 50, 5513, 2002. 

Introducing Novel Flavonoid Compounds 3.16.3.1 Chalcones, Aurones, and Flavonols... 

Rhodes, M.J.C. and Price, K.R., Analytical problems in the study of flavonoid compounds in onions. Food Chem., 57, 113, 1996. 

Morris, P.F., Bone, E., and Tyler, B.M., Chemotropic and contact responses of Phytophthora sojae hyphae to soybean isoflavonoids and artificial substrates. Plant Physiol, 117, 1171, 1998. Zerback, R., Dressier, K., and Hess, D., Flavonoid compounds from pollen and stigma of Petunia hybrida inducers of the vir region of the Agrobacterium tumefaciens Ti plasmid. Plant Scl, 62, 83, 1989. 

Kosslak, R.M. et al., Strain-specific inhibition of nod gene induction in Bradyrhizobium japonicum by flavonoid compounds, Appl Environ. Microbiol, 56, 1333, 1990. 

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