Quercetin diglucoside

Silk dyed with Reseda luteola, Sophora japonica and Allium cepa Rutin, quercetin, kaempferol, kaempferol 3,7 diglucoside, quercetin 4 glucoside, luteolin HCI/Me0H/H20, HCOOH/MeOH, H2EDTA/ACN/MeOH A H20 B ACN C H20 with HCOOH 350, 450, 490 nm/ ESI( ) Column C4 6... 

Development of suitable sample handling, extraction, and HPLC/diode array detector (DAD) based methods for the analysis of flavonoids and their conjugates in four varieties of onions were described (125). The predominant flavonoids in onions (white, brown, red, and pink varieties) were quercetin mono- and diglucosides, which accounted for approximately 80% of the total flavonol fraction. 

AF Finger, UH Engelhardt, V Wray. Flavonol glycosides in tea—kaempferol and quercetin rhamno-diglucosides. J Sci Food Agric 55 313-321, 1991. 

Flavonols that accumulate in plant tissues are almost always in the form of glycosylated conjugates. The main flavonols in onions are quercetin- 4 -O-glucoside and quercetin-3,4 -0-,diglucoside with smaller amounts of isorham-netin-4 -0-glucoside (Fig. 1.3) [Mullen et al., 2004]. 

Equisetum silvaticum (6) similar pattern of green kaempferol glycoside zones as in sample 5. In addition, the yellow-orange zones of quercetin-3, 7-diglucoside (R, 0.4) and isoquercitrin (R, — 0.7) as in E. arvense (1,2). 

A wide range of kaempferol and quercetin glycosides has also been reported, among them quercetin 3-rutinoside, kaempferol 3-rutinoside and quercetin 3-rutinoside 4 -diglucoside [16]. 

It has been reported that the epidermis of onion scales contains only glucosides of quercetin, while the dry outer skin contains quercetin mainly in its free state [73]. Quercetin 4 -glucoside and other diglucosides are... 

Fig. (10). HPLC chromatogram of red onion anthocyanins and other phenols (1) quercetin 3,4 -diglucoside, (2) quercetin 4 -glucoside, (3) isorhamnetin 4 -glucoside, (4) cyanidin 3-glucoside, (5) cyanidin 3-arabinoside, (6) cyanidin 3-malonylglucoside, and (7) cyanidin 3-malonylarabinoside. HPLC conditions RP Cig column (12 x 0.4 cm particle size 5 im). Mobile phase acidified water (5% formic acid) (A) and methanol (B). Gradient 0 min- 15% B, 15 min- 35% B, 25 min- 40% B. Flow rate 1 mL/min.

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