Flavonol glucosides

Fig. 2.56. HPLC chromatogram of (a) Golden peel and (b) Golden pulp extracts at 280 nm. Peaks 1 = procyanidin B3 2 = procyanidin Bl 3 = ( + )-catechin 4 = procyanin B2 5 = chlorogenic acid 6 = ( — )-epicatechin 7 = caffeic acid 8 = phloretin derivative 9 = phloridzin 10 = rutin 11, 12 and 13 = flavonol glucosides. Reprinted with permission from A. Escarpa et al. [160].

Figure 1. Postulated pathway for the enzymatic synthesis of polymethylated flavonol glucosides in Chrysosplenium americanum GT, O-glucosyl-transferase OH, hydroxylase OMT, O-methyl transferase.

Regulation of Flavonoid Synthesis in C. americanum. Biosynthesis of methylated flavonol glucosides seems to be under tight regulation, not only by the substrate specificity of the enzymes involved, but also by other factors, among which are (a) the strict position specificity of these enzymes towards their hydroxylated or partially methylated substrates (b) the apparent difference in microenvironment of the different methyl-transferases, whereby those earlier in the pathway utilized aglycones whereas later enzymes accepted only glucosides as substrates (c) the subtle characteristic differences in methyl-transferases with respect to their pH optima, pi values and requirement for Mg ions, despite their similar molecular size ... 

Price, K.R., Bacon, J.R., and Rhodes, M.J.C., Effect of storage and domestic processing on the content and composition of flavonol glucosides in onion Allium cepd), J. Agric. Food Chem., 45, 938, 1997. 

Smith, G.J. and Markham, K.R., Tautomerism of flavonol glucosides relevance to plant UV protection and flower colour, J. Photochem. Photobiol A, 118, 99, 1998. 

LC-ESI-MS analyses allowed the detection of intact flavonol glucosides (rutin) in plasma of healthy volunteers after the consumption of tomato extract [65]. 

KHOURI, H.E., ISHIKURA, N., IBRAHIM, R.K., Fast protein liquid chromatographic purification and some properties of a partially 0-methylated flavonol glucoside 2 -/5 -0-methyltransferase. Phytochemistry, 1986, 25, 2475-2479. 

White cabbage is rich in flavonol glucosides, where acylated and unacylated tri- and tetraglucosides of kaempferol and quercetin have been isolated and identified (Nielsen et al., 1993 1998). In broccoli florets, the main flavonol glycosides were identified as sophorosides of quercetin and kaempferol, but all the fiavonoids have not yet been determined. The fiavonols were present in raw florets at 65 mg kg and 166 mg kg fresh weight, respectively (Price et al.,... 

Genes affecting reaction to nutritional factors including phosphorus, iron, and chloride and the presence/absence of a constitutive nitrate reductase enzyme occur in soybean. Palmer et al. (2004) discuss these as well as leaf flavonol glucosides. 

Czimmer, A. G. 1936. The pharmacological action of flavonol glucoside of the species Forsythia. Arch, exptl. Pathol. Pharmahol. 188, 587. 

Lee J, Jang DS, Yoo NH, Lee YM, Kim JH, Kim JS (2010) Single-step separation of bioactive flavonol glucosides from Osteomeles schwerinae by high-speed counter-current chromatography. J Sep Sci 33 582-586... 

Tsushida, T. Suzuki, M. (1996). Content of flavonol glucosides and some properties of enzymes metabolizing the glucosides in onion. Nippon Shokuhin Kagaku Kogaku Kaishi, 43, 642-649. 

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