Showing papers on "Flavanone published in 1991"
TL;DR: It is shown that the presence of hydroxyl groups in the B ring of flavonoids is essential for their scavenger activity, and the existence of a hydroxYL at C-3 enhances the scavenger ability of Flavonoids.
297 citations
TL;DR: In this paper, the authenticity of the ethylene-forming enzyme was fully recovered in vitro for the first time, and the enzyme was extracted in a soluble form from fruits of melon (Cucumis melo ).
277 citations
TL;DR: The natural polymethoxyflavone gardenin D has shown a potency comparable to that of (+)-catechin and higher than that of silybin, and may be considered as a new type of natural antioxidant with potential therapeutical applications.
Abstract: The antiperoxidative effects of 35 phenolic compounds, most of them belonging to the flavonoid class, were investigated using CCl4-induced peroxidation of rat liver microsomes. This system was rather insensitive to gallic acid, methyl gallate and ellagic acid. Nevertheless it was inhibited by flavonoids and structure/activity relationships were established. The most potent compounds were gardenin D, luteolin, apigenin (flavones), datiscetin, morin, galangin (flavonols), eriodictyol (flavanone), amentoflavone (biflavone) and the reference compound, (+)-catechin. The natural polymethoxyflavone gardenin D has shown a potency comparable to that of (+)-catechin and higher than that of silybin. Thus, it may be considered as a new type of natural antioxidant with potential therapeutical applications.
255 citations
TL;DR: Results indicate that flavones or flavonols that contain free 5- and 7-hydroxyls are potent inhibitors of P-450 induced by beta-naphthoflavone (P-450IA1 and/or P- 450IA2) and may potentially be useful as chemopreventive agents against hydrocarbon-induced carcinogenesis.
53 citations
TL;DR: In this article, the diastereomers of prunin, naringin, neohesperidin, and narirutin were separated by high-performance liquid chromatography elution in the reversed phase mode on a β-cyclodextrin bonded stationary phase (Cyclobond I).
50 citations
TL;DR: In this paper, radioactively labeled acetate and phenylalanine were fed to grapefruit seedlings to characterize the biosynthesis and subsequent metabolic fate of the flavanone glycoside naringin.
22 citations
TL;DR: In this paper, two new complicated flavanone derivatives containing stilbenoid nuclei were isolated from the roots of Sophora leachiana and the structures of leachianones B and C were established by means of spectroscopic analysis.
22 citations
TL;DR: In this article, Pinostrobin 5-glucoside, a novel flavanone glycoside, was isolated from the bark of Prunus cerasus.
21 citations
TL;DR: In this article, four new flavonoids from the roots of Euchresta formosana were characterized as 5,5′-dihydroxy-8-γ,γ-dimethylallyl-{(6,6)-dimethylpyrano(2,3 :4′,3′)}-coumaronochromone euchretin E.
17 citations
TL;DR: In this article, the aereal parts of Tephrosia leiocarpa afforded two new flavanones, 5-hydroxy-7-methoxy-8-(3-hydrox-3-methyl trans -but-1-enyl)flavanone, named tephroleocarpin A and B, respectively.
17 citations
TL;DR: In this article, the synthesis of (2-phenyl)dihydrobenzopyrone-and 2-hydroxychalcone thiosemicarbazones (1c, 2c, 3c, and 7c) was described.
TL;DR: A malonic acid ester derivative of the flavanone naringin was found to be abundant in the young leaves and fruits of grapefruit plants, but not in the mature leaves and fruit.
TL;DR: In this article, the synthesis of pyrano[2,3-c]pyrazole derivatives 4, 5, and 7 starting from (E)-(1, 3-dimethyl-5-hydroxy-4-pyrazolyl)-3-phenyl-2-propen-1-one (2) is reported.
TL;DR: A series of new flavonoid aglycones have been identified in the frond exudates of the fern Cheilanthes argentea, in five species of Notholaena, in Pityrogramma triangularis, and in Platyzoma microphylla.
Abstract: A series of new flavonoid aglycones have been identified in the frond exudates on the fern Cheilanthes argentea, in five species of Notholaena, in Pityrogramma triangularis, and in Platyzoma microphylla. These aglycones comprise several rare flavonoids and five novel natural products: 5,7,8-trihydroxy-3-methoxy-6-methyl flavone, 3-5,2'-trihydroxy-7,8,4'-trimethoxy flavone, 5,2'-dihydroxy-3,7,8-trimethoxy flavone, 5,7,4'-trihydroxy-2'-methoxy flavanone, and 3,5,4'-trihydroxy-6,7-8-trimethoxy flavone. The novel flavonoids were characterized by their NMR spectral data
TL;DR: Callus cultures were established to produce prenylated flowanones as well as pterocarpans as mentioned in this paper, and the effect of various media on the production of flavanones was also investigated.
Abstract: Callus cultures were established to produce prenylated flowanones as well as pterocarpans. The effect of various media on the production of flavanones was also investigated
TL;DR: Analysis by GC-MS separated 50 components of bud exudate from P. sieboldii of which 36 were phenolics and the bulk was composed of the flavanone naringenin and its methyl ethers sakuranetin and isosakuranETin, together with their corresponding chalcones.
TL;DR: In this article, a mechanism of pyrolysis and elucidation of the structures of rearranged ions (for example [M + 146 + H]+), often generated in the FD-mass spectra of glycosides, are presented.
TL;DR: In this article, the conversion of flavanone and 7-hydroxyflavanone in alkaline water and heavy water and of the same compounds and of 4′ -nitroflavanones in alkali-methanolic media into the corresponding substituted chalcones was studied kinetically and spectroscopically.
TL;DR: In this paper, the authors examined the origin of double peaks in the gas chromatograms of trimethylsilyl derivatives of flavanone aglycones and defined the effects of derivatization temperature, time and capillary column injection technique on the rate of interconversion.
TL;DR: In this article, 17 flavonoids were isolated from the roots of Scutellaria luzonica Rolfe, including two flavanones, a chalcone and a glucoside.
Abstract: Seventeen flavonoids were isolated from the roots of Scutellaria luzonica Rolfe. These compounds in elude thirteen flavones (1–13), two flavanones (14–15), a chalcone (16) and a flavone glucoside (17).
TL;DR: Ratibinolide II, a new eudesmanolide, and the known flavanone hispidulin have been isolated from Ratibida latipalearis and the structure elucidation of the new compound was unequivocally established by spectral and X-ray crystallographic analyses.
Abstract: Ratibinolide II, a new eudesmanolide, and the known flavanone hispidulin have been isolated from Ratibida latipalearis. The structure elucidation of the new compound was unequivocally established by spectral and X-ray crystallographic analyses.
TL;DR: From the dried leaves of Pyracantha coccinea, a new acylated glucoside, 3′,4′-diacetoxy-5-hydroxy-7- O -β- d -tetraacetylglucopyranosyloxy flavanone was isolated and its structure was determined by spectral procedures.
TL;DR: In this paper, an enzyme-linked immunoassay (ELISA) is described; it can be used for the qualitative analysis of flavanone neohesperidosides in citrus.
Abstract: An enzyme-linked immunoassay (ELISA) is described; it can be used for the qualitative analysis of flavanone neohesperidosides in citrus.Naringin, a hapten, was conjugated with bovine serum albumin (BSA) at the position of sugar moeity of naringin with BrCN. Using the alkaline diethylene glycol method of Davis, the coupling ratio was found to be 18 mol of naringin/mol BSA. The naringin-BSA conjugate at 2.53 mg was emulsified by mixing with Freund's complete adjuvant and injected intradermally to a rabbit biweekly 4 times to make the anti-naringin antibody. The assay was carried out by direct competitive solid phase immunoassay using anti-naringin antibody and naringin-alkaline phosphatase conjugate prepared by the same conjugation method as hapten-BSA conjugate.The antibody showed a marked specificity for the dissaccharide linkage at position C7 of flavanone glycosides. Flavanone neohesperidosides were highly immunoreactive ; prunin was less reactive, whereas rutinosides and aglycones were not immunoreactive.The assay showed a high sensitivity within a range of 0.120 ng naringin. Therefore, leaf extracts had to be diluted 10- to 160- fold, corresponding to 0.1 mg6.25 μg leaf fresh weight, respectively. Flavanone neohesperidosides could be detected qualitatively by the naked eye by the color change from yellow to transparent in accordance with the increase in the amount of flavanone neohesperidosides.Thus, the qualitative ELISA of flavanone neohesperidosides could be carried out accurately using 10-fold dilution of the extracts. An average of 2, 000 samples of citrus seedlings could be analyzed within 10 days including the pretreatment of the leaf extract and the ELISA.Fruit juice and leaf extracts of 40 cultivars and some hybrid seedlings were analyzed qualitatively for flavanone neohesperidosides by ELISA and high performance liquid chromatography (HPLC). The results of the analysis for flavanone neohesperidosides coincides completely by ELISA for leaf extracts and by HPLC for fruit juice and leaf extracts.Thus, we conclude that the ELISA method described in this paper is well suited for the analysis of flavanone neohesperidosides, particularly when a large number of samples must be analyzed. For example, the method would be useful to study the inheritance of citrus bitter component by analyzing leaves of the young citrus seedlings.
TL;DR: In this paper, a new synthesis of chromones and flavones based on the ortho-directed metalation of methoxymethyl aryl ethers with alkyllithium reagents is described.
Abstract: A new synthesis of chromones and flavones based on the ortho-directed metalation of methoxymethyl aryl ethers with alkyllithium reagents is described. It entails reaction of the ortho-lithiated intermediates with a conjugated unsaturated aldehyde followed by oxidation of the allylic alcohol product with «periodinane» to yield an ortho-allylic ketone. The latter on heating in acetic acid undergoes loss of the methoxymethyl protecting group and cyclization to a chromanone (or flavanone, if a β-phenyl substituent is present). Dehydrogenation by treatment with pyrrolidone hydrotribromide (PHT) in dimethyl sulfoxide yields the corresponding chromones (or flavones). This synthetic approach appears general in its applicability
TL;DR: Inheritance of flavanone neohesperidosides, the bitter component, in citrus was studied using about 9,000 F1 seedlings obtained from 131 crosses and it was concluded that the formation of citrus bitter component is controlled by two dominant multiple genes.
Abstract: Inheritance of flavanone neohesperidosides, the bitter component, in citrus was studied using about 9, 000 F1 seedlings obtained from 131 crosses. Flavanone neohesperidosides in leaf extract were analysed with a competitive enzyme-linked immunosorbent assay (ELISA) using rabbit anti-naringin antiserum derived from naringin-bovine serum albumin conjugate and alkaline phosphatase-naringin conjugate. This antiserum is specific for the flavanone neohesperidosides, i. e., naringin, neohesperidin and poncirin, and does not react with the non-bitter isomeric rutinosides, i. e., narirutin, hesperidin and didymin.Inheritance of flavanone neohesperidoside was proposed as follows:1. Formation of bitterness for flavanone neohesperidosides is controlled by dominant genes.and pomelo cultivars are homozygous for 1 or 2 pairs of dominant genes.2. Among progenies of interspecific crosses between cultivars of mandarins, oranges and others which do not contain neohesperidoside (N-), the bitter compounds were not detected in leaf extracts of any F1 seedlings. Thus, these cultivars are homozygous for the recessive genes.3. Among crosses between cultivars which contain neohesperidosides (N+), except the pomelo, and those cultivars which do not contain the bitter constituents (N-), the seedling progenies segregated into N+ : N- ratios of 1 : 1 or 3 : 1. Therefore, the N+ parents were designated as the (1 : 1) or as the (3 : 1) segregant types, respectively.4. When the (1 : 1) segregant cultivars (N+) were selfed or crossed with the same (1 : 1) genotype, the segregation ratio, N+ : N-, was 3 : 1. When the (1 : 1) type was hybridized with the (3 : 1) type, the progenies segregated into a N+ : N- ratio of 7: 1, whereas selfing or crossing of two (3 : 1) types resulted in a N+ : N- ratio of 15 : 1. From these segregation ratios, it was concluded that the formation of citrus bitter component, flavanone neohesperidoside, is controlled by two dominant multiple genes.
Journal Article•
Journal Article•
TL;DR: In this article, a structure composed of a unite flavone liee par son X en α au C en β d'une unite hydroxydihydrochalcone, avec tous les groupements carbonyl presents en tant que leurs derives methylimine.
Abstract: C 32 H 29 N 2 O 2 cristallise dans P2 1 /c avec a=10,090, b=16,662, c=16,478 A, β=114,68 o , Z=4, T=123 K; affinement jusqu'a R=0,0423. La structure est composee d'une unite flavone liee par son X en α au C en β d'une unite hydroxydihydrochalcone, avec tous les groupements carbonyl presents en tant que leurs derives methylimine. L'hydrogene de l'hydroxy est lie de facon intramoleculaire par l'hydrogene a lm'azote adjacent de l'imine