Backbone of a flavonol, substituent numbers are indicated.
Flavonols are a class of flavonoids that have the 3-hydroxyflavone backbone (IUPAC name: 3-hydroxy-2-phenylchromen-4-one). Their diversity stems from the different positions of the phenolic –OH groups. They are distinct from flavanols (with "a") such as catechin, another class of flavonoids, and an unrelated group of metabolically important molecules, the flavins (with "i"), derived from the yellow B vitamin riboflavin.
Flavonols are present in a wide variety of fruits and vegetables. In Western populations, estimated daily intake is in the range of 20–50 mg per day for flavonols. Individual intake varies depending on the type of diet consumed.[1]
The phenomenon of dual fluorescence (due to excited state intramolecular proton transfer or ESIPT) is induced by tautomerism of flavonols (and glucosides) and could contribute to plant UV protection and flower colour.[2]
Besides being a subclass of flavonoids, flavonols are suggested by a study of cranberry juice to play a role along with proanthocyanidins, in the juice's ability to block bacterial adhesion, demonstrated by the compressing the fimbria of E. coli bacteria in the urinary tract so as to greatly reduce the ability of those bacteria to stay put and initiate an infection.[3] Flavonol aglycones in plants are potent antioxidants that serve to protect the plant from reactive oxygen species (ROS).[4]
^Cermak R, Wolffram S (October 2006). "The potential of flavonoids to influence drug metabolism and pharmacokinetics by local gastrointestinal mechanisms". Curr. Drug Metab. 7 (7): 729–44. doi:10.2174/138920006778520570. PMID 17073577. Archived from the original on 2012-07-20.
^Smith, Gerald J.; Markham, Kenneth R. (1998). "Tautomerism of flavonol glucosides: relevance to plant UV protection and flower colour". Journal of Photochemistry and Photobiology A: Chemistry. 118 (2): 99–105. doi:10.1016/s1010-6030(98)00354-2.
^"Juicy news about cranberries". medicalxpress.com. Retrieved 13 April 2018.
^Nakabayashi R, Yonekura-Sakakibara K, Urano K, Suzuki M, Yamada Y, Nishizawa T, Matsuda F, Kojima M, Sakakibara H, Shinozaki K, Michael AJ, Tohge T, Yamazaki M, Saito K. (2014). "Enhancement of oxidative and drought tolerance in Arabidopsis by overaccumulation of antioxidant flavonoids". Plant J. 77 (3): 367–79. doi:10.1111/tpj.12388. PMC 4282528. PMID 24274116.{{cite journal}}: CS1 maint: multiple names: authors list (link)
tautomerism of flavonols (and glucosides) and could contribute to plant UV protection and flower colour. Besides being a subclass of flavonoids, flavonols are suggested...
Dicotyledons and Monocotyledons of Angiosperms. The total average intake of flavonols and flavones in a normal diet is estimated as 23 mg/day, to which kaempferol...
common buckwheat seeds (0.01% dry weight). Rutin is one of the primary flavonols found in 'clingstone' peaches. It is also found in green tea infusions...
ketone-containing compounds and as such, anthoxanthins (flavones and flavonols). This class was the first to be termed bioflavonoids. The terms flavonoid...
Compared to other processes, Dutch process cocoa contains lower amounts of flavonols (antioxidants). The effect this has on nutritional value is disputed....
In enzymology, a flavonol synthase (EC 1.14.11.23) is an enzyme that catalyzes the following chemical reaction : dihydroflavonol + 2-oxoglutarate + O 2...
Quercetin is a plant flavonol from the flavonoid group of polyphenols. It is found in many fruits, vegetables, leaves, seeds, and grains; capers, red onions...
subcategory known as flavonols, which includes the yellow pigment - quercetin. Like other flavonoids, the concentration of flavonols in the grape berries...
arable ground in the British Isles. Polygonum aviculare contains the flavonols avicularin, myricitrin and juglanin. The flavanoids astragalin and betmidin...
polyphenols present include flavonoids, such as anthocyanins, flavanols, flavonols and phenolic acids, such as hydroxybenzoic acid and hydroxycinnamic acid...
short-term consumption of chocolate up to 105 grams and 670 milligrams of flavonols per day. Flavanols found in dark chocolate include the monomers catechin...
Nielsen; Niels Agerbirk (2011). "Polymorphism for novel tetraglycosylated flavonols in an eco-model crucifer, Barbarea vulgaris". Journal of Agricultural...
production of a diverse array of natural products. Methoxylated and oxygenated flavonols, flavones, and triterpenes accumulate on the vegetative and floral buds...
caerulea var. kamtschatica) showed the presence of iridoids, anthocyanins, flavonols, flavanonols, flavones, flavan-3-ols, and phenolic acids. While sugars...
Vrhovsek U, Stefanini M, Velasco R (2006). "Metabolite profiling of grape: Flavonols and anthocyanins". J Agric Food Chem. 54 (20): 7692–702. doi:10.1021/jf061538c...
Oryza is a genus in the plant family Poaceae, of which Oryza sativa (cultivated rice) is a member. Oryza is a genus of 24 species, most of which are annual...
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