Topic
Flavanone
About: Flavanone is a research topic. Over the lifetime, 1965 publications have been published within this topic receiving 54729 citations. The topic is also known as: flavanones.
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TL;DR: In this paper, the 2 S configuration and 3-hydroxy-flavanones of 2 R, 3 R configuration, having equatorial 2-aryl substituents in the former or diequatorial 2,3-substituents of the latter, exhibit a positive Cotton effect due to the n → π * transition (∼ 330 nm) and a negative Cotton effect in the n α π ∆ * region(∼ 280-290 nm).
412 citations
TL;DR: Naturally occurring polyphenolics tested followed the expected general trends of phenolic acids and flavonoids, and synthetic antioxidant food additives conventionally used in the food industry were less effective antioxidants than ascorbic acid.
Abstract: Antioxidant capacity for a wide range of natural or synthetic polyphenolics was comprehensively evaluated by vitamin C equivalent antioxidant capacity (VCEAC) assay using free blue/green ABTS radicals. The polyphenolics tested are grouped into the following categories: vitamins (β-carotene, α -tocopherol, vitamin A, and vitamin C), phenolic acids (benzoic acid, phenylacetic acid, cinnamic acid, and their derivatives), flavonoids (anthocyanidin, flavanol, chalcone, flavanone, flavone, flavonol, isoflavone, and their derivatives), synthetic food additives (BHA, BHT, TBHQ, and PG), and other miscellaneous polyphenolics (ellagic acid, sesamol, eugenol, thymol, etc.). A positive linear relationship between VCEAC and the number of free OH groups around the flavonoid framework was found, whereas, for phenolic acids, the linear relationship was not as good as with the flavonoid aglycones. Groups of chemicals having comparable structures generally showed similar trends. Polyphenolics commonly showed a higher VCEAC...
381 citations
TL;DR: It is suggested that prenylchalcones and prenylflavanones found in hops and beer protect human LDL from oxidation and thatPrenylation antagonizes the prooxidant effects of the chalcone, CN, and the flavanone, NG.
Abstract: Prenylated flavonoids found in hops and beer, i.e., prenylchalcones and prenylflavanones, were examined for their ability to inhibit in vitro oxidation of human low-density lipoprotein (LDL). The oxidation of LDL was assessed by the formation of conjugated dienes and thiobarbituric acid-reactive substances (TBARS) and the loss of tryptophan fluorescence. At concentrations of 5 and 25 μM, all of the prenylchalcones tested inhibited the oxidation of LDL (50 μg protein/ml) induced by 2 μM copper sulfate. The prenylflavanones showed less antioxidant activity than the prenylchalcones, both at 5 and 25 μM. At 25 μM, the nonprenylated chalcone, chalconaringenin (CN), and the nonprenylated flavanone, naringenin (NG), exerted prooxidant effects on LDL oxidation, based on TBARS formation. Xanthohumol (XN), the major prenylchalcone in hops and beer, showed high antioxidant activity in inhibiting LDL oxidation, higher than α-tocopherol and the isoflavone genistein but lower than the flavonol quercetin. When combined,...
347 citations
TL;DR: The strong antiproliferative activities of the polymethoxylated flavones suggest that they may have use as anticancer agents in humans.
Abstract: Citrus fruits contain high concentrations of several classes of phenols, including numerous hydroxycinnamates, flavonoid glycosides, and polymethoxylated flavones. The latter group of compounds occurs without glycosidic linkages and has been shown to inhibit the proliferation of a number of cancer cell lines. This antiproliferative property was further demonstrated against additional human cancer cell lines, and the antiproliferative actions of a series of synthetic methoxylated flavones were also studied. Similar to the naturally occurring compounds, the synthetic compounds exhibited strong antiproliferative activities. In many cases the IC(50) values occurred below 10 microm. Other hydroxylated flavone and flavanone aglycons also exhibited antiproliferative activities against the cancer cell lines, with the flavones showing greater activities than the flavanones. Glycosylation of these compounds removed their activity. The strong antiproliferative activities of the polymethoxylated flavones suggest that they may have use as anticancer agents in humans.
344 citations
TL;DR: It was found that these three flavonoids exhibited comparable antioxidant activities against different oxidants leading to the conclusion that the presence of ortho -catechol group (3',4'-OH) in the B-ring is determinant for a high antioxidant capacity.
Abstract: The antioxidant and prooxidant activities of flavonoids belonging to several classes were studied to establish their structure-activity relationships against different oxidants. Special attention was paid to the flavonoids quercetin (flavone), taxifolin (flavanone) and catechin (flavanol), which possess different basic structures but the same hydroxylation pattern (3,5,7,3'4'-OH). It was found that these three flavonoids exhibited comparable antioxidant activities against different oxidants leading to the conclusion that the presence of ortho-catechol group (3',4'-OH) in the B-ring is determinant for a high antioxidant capacity. The flavone kaempferol (3,5,7,4'-OH), however, in spite of bearing no catechol group, also presents a high antioxidant activity against some oxidants. This fact can be attributed to the presence of both 2,3-double bond and the 3-hydroxyl group, meaning that the basic structure of flavonoids becomes important when the antioxidant activity of B-ring is small.
340 citations