Rhamnetin

Rhamnetin (3,3 -4, 5-tetrahydroxy-7-methoxy flavone, 7-methyl quercitin) [90-19-7] M 316.3, m >300"(dec), several phenolic pKs -7-10.5. Crystd from EtOH. 

Europe. To extract the dye, the juice of unripe berries is pressed out and then dried. The coloring matter in the dye is a mixture of three organic compounds rhamnazin, rhamnetin, and quercetin. 

Silk and wool fibres of Coptic textiles from fourth to twelfth century Carminic acid, laccaic acids A, B, C and E, xantholaccaic acid A, purpurin, xanthopurpurin, alizarin, monochloroalizarin, dichloroalizarin, ellagic acid, luteolin, apigenin, rhamnetin, indirubin HCI/EtOH, pyridine A ACN B H20 with TFA 278, 350 nm/ESI (+)... 

Fig. 2 Relative effects of rhamnetin, isorhamnetin and total extract from pollen of Phleum pratense on in vitro germination of pollen of Elytrigia repens. Data points are means and standard errors from 50 replicate samples.

The retention behaviour of flavonoids has also been extensively studied on silica stationary phases using heptane, benzene or dichloromethane as weaker components of the binary mobile phase and ethyl acetate and methyl ethyl ketone as modifier. Flavones (3-hydroxy, 5-hydroxy and 7-hydroxyflavone, tectochrysin, chrysin, apigenin, genkwanin, baicalein), flavonols (galangin, pilloin, kaempferol, rhamnetin, quercetin, robinetin,... 

Fig. 2.90. Electropherograms of sterile root exudate before (a) and after incubation with Mesorhizobium loti (b) and Rhizobium leguminosarum bv. trifolii (c). From their UV spectra, peaks 1-6 were identified as resorcinol, rhamnetin, catechin, quercetin glycoside, quercetin aglycone and hesperidin. Differences in the retention times of the same compounds in different samples could be due to the variations in buffer temperature or sample composition. Reprinted with permission from H. L. Steele et al. [213].

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-... 

Glucoside-3 -sulfate Quercetin 7-methyl ether (rhamnetin) Calorphus elongatus cuhns Restionaceae 367... 

Imperato, F., Rhamnetin 3-0-laminaribioside from Pteridium aquilinum. Phytochemistry, 45, 1729, 1997. 

Vaishnov, M.M. and Gupta, K.R., Rhamnetin 3-0-gentiobioside from Cassia fistula roots, Fitoterapia, 67, 78, 1996. 

Ozipek., M. et al., Rhamnetin 3-n-coumaroylrhamnoside from Rhamnus petiolaris. Phytochemistry, 37, 249, 1994. 

N.A. Campanula rotundifolia L. C. palustris L. Lutein-7-primveroside, luteolin-7-0-beta-D-glucopyranosil, rhamnetin-3-0-beta-D-galactoside, esculetin, caffeic, n-coumaric, ferulic acids.302 For faintness or a weak heart, stop bleeding, reduce swelling.274... 

Honey conveys both phenolic antioxidants and increases plasma antioxidant capacity (Nagai et al., 2001 Schramm et al., 2003). Honey contains flavanoids such as rhamnetin, kaempferol, naringenin, quercetin, and apigenin (see Chapter 31). 

Rhamnetin (= 3,5,3, 4 -Tetrahydroxy-7-methoxyflavone) (flavonol) Cistus spp. (Cistaceae) many Asteraceae Lamiaceae Aminopeptidase N (54% inhibition at 300 pM) [63]... 

Eugenol, the primary component of clove s volatile oils, functions as an antiinflammatory substance. In animal studies, the addition of clove extract to diets already high in anti-inflammatory components (like cod liver oil, with its high co-3 fatty acid content) brings a synergistic effect. In some studies, it further reduces inflammatory symptoms by another 15-30%. Clove also contains a variety of flavonoids, including kaempferol and rhamnetin, which also contribute to clove s anti-inflammatory and antioxidant properties. Another constituent of clove oil, /J-caryophyllene, also contributes to the anti-inflammatory activity (Ghelardini et al., 2001). 

Rhamnetin (= 3,5,7,3, 4 -Pentahydroxv-flavone 7-methyl ether Quercetin 7-methyl ether)... 

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