Kaempferol-3-glucuronide

Harborne and Saleh (1971) confirmed the presence of quercetin 3-arabinoside in the leaves of fennel and three other flavo-nol glycosides, kaempferol 3-arabinoside, kaempferol 3-glucuronide and quercetin 3-glucuronide. A chemotypic characterization of populations of fennel based on the occurrence of glycosides has been attempted. The dried distillation residue of fennel fruits contains 14-22% protein and 12-18% fat and is suitable for stock feed (Weiss, 2002). 

Figure 2.16 HPLC profile of flavonols of a Cabernet Sauvignon grape skins extract recorded at wavelength 360nm. (1) myricetin glucuronide, (2) myricetin gluco-side, (3) quercetin glucuronide, (4) quercetin glucoside, (5) quercetin rutinoside, (6) kaempferol glucuronide, (7) kaempferol glucoside, (8) unidentified flavonol...

Myricetin glucoside Quercituron Isoquercitrin Kaempferol glucuronide Astragalin Myricetin rutinoside Rutin Nicotiflorin... 

The main kaempferol metabolite in human plasma is the 3-glucuronide. The three major metabolites of quercetin are quercetin-3-glucuronide, quercetin-3 -sulfate, and iso-rhamnetin-3-glucuronide (found at 0.1 to 1 iuM). These are accompanied by lesser amounts of the 4 -glucuronides of quercetin and isorhamnetin, and several uncharacterized metabol-... 

Oliveira, E.J. and Watson, D.G., In vitro glucuronidation of kaempferol and quercetin by human UGT-1A9 microsomes, FEES Lett., 471, 1, 2000. 

Glucuronide Kaempferol 7-methyl ether (rhamnocitrin) Centaurea bracteata aerial parts Compositae 275... 

Recently, nine flavonol glycosides including 3-/ -monoglucosides and 3- -glucuronides of quercetin and kaempferol were detected and purified from strawberry fruit (168). A summary of phenolic compounds in soft fruits is presented by Green (40). 

Wang et al. studied the disposition of quercetin and kaempferol in 10 adult volunteers following oral administration of ginkgo biloba extract. Quercetin and kaempferol were determined in human urine using reversed-phase HPLC. Quercetin and kaempferol were excreted from urine mainly as glucuronides. " An HPLC protocol using the ion-pairing... 

Flavonols are also present, particularly in the skin. 3-Glucosides and 3-glucuronides of kaempferol, quercetin and myricetin have been reported (8-97 mg/kg) [16]. 

The external part of the fruit contains several quercetin and kaempferol derivatives, mainly quercetin and kaempferol 3-glucosides and glucuronides. However, other less frequent glycosidic combinations have been reported in specific cultivars [32 33]. 

The 3-glucuronide and 3-glucoside derivatives of kaempferol and quercetin are the main flavonoid constituents. They particularly accumulate in the external tissues of the fruit [36]. In a study of 20 cultivars the content varied from 21 to 174 mg/kg f.w. 

Kaempferol 3-glucoside and 3-glucuronide were the only flavonoids found in endive [66]. In this case, the kaempferol content of the external leaves reached 225 mg/kg, while the inner leaves only contained 5 mg/kg. 

The mass spectrometric fragmentation in combination with a metabolic pathway was explored in profiling components in bile samples. The in vivo metabolic reactions of fiavonols were mainly methylation, glucuronidation, and sulfation (Mullen et ah, 2004 Day et al., 2000 Williamson et al., 2000). The neutral losses of 15, 80, and 176 Da observed in MS/MS spectra were used to characterize methyl, sulfate, and glucuronide conjugate, respectively. In comparison with the blank sample, a total of 31 quercetin-based and 12 kaempferol-based compounds were identified in rat biles after oral and intravenous (IV) administration of AB-8-2. All the components were sorted and numbered by the retention time under the same chromatographic condition. The parent constituents and metabolites are listed in Tables 18.2 and 18.3, respectively. 

The rat urine sample after oral administration of AB-8-2 was analyzed by using the method established. In one analytical run, 51 constituents including 35 di-glucuronidated metabolites, 12 monoglucuronidated metaboKtes and 4 flavonol aglycones were characterized. The main aglycone of metaboKtes was quercetin or kaempferol (Table 18.4). 

Kaempferol, kaempferol-3-O-P-D-galactopyranoside kaempferol-3-O-P-D-rutinoside (nicotiflorin), quercetin, quercetin-3-0-P-D-glucuronide methyl ester, quercetin-3-O-P-D-glucopyranoside (isoquercitrin), quercetin-3-O-P-D-galactopyranoside (hyperoside)... 

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