Showing papers on "Flavanone published in 1998"
TL;DR: In this investigation, effects of naturally occurring flavonoids on epidermal cyclooxygenase/lip oxygengenase were studied using five selected derivatives: flavanone, apigenin, quercetin (flavonol), amentoflavone and ginkgetin (biflavone) because eicosanoids generated in the epidermis are believed to be involved in various biological activities of the skin.
Abstract: Although there have been numerous topical applications of plant extracts having flavonoids known as anti-inflammatory compounds, only a few studies were reported concerning effects of flavonoids on epidermal cyclooxygenase/lipoxygenase. In this investigation, effects of naturally occurring flavonoids on epidermal cyclooxygenase/lipoxygenase were studied using five selected derivatives: flavanone, apigenin (flavone), quercetin (flavonol), amentoflavone and ginkgetin (biflavone) because eicosanoids generated in the epidermis are believed to be involved in various biological activities of the skin. Microsomal and cytosolic fractions were obtained from guinea-pig epidermal homogenate by centrifugation and used as a source for cyclooxygenase and lipoxygenase. It was found that quercetin inhibited both cyclooxygenase and lipoxygenase, being more potent against lipoxygenase, while flavanone and apigenin did not show any inhibition. Amentoflavone, one of the biflavones tested, showed potent and selective inhibitory activity on cyclooxygenase (IC50 = 3 microM) which was comparable to indomethacin (IC50 = 1 microM). In contrast, structurally similar ginkgetin possessed weak inhibitory activity on cyclooxygenase. The in vivo effects of these flavonoids on the normal and diseased skin remain to be studied.
282 citations
TL;DR: Differentiation of orange juice varieties and mixtures containing tangor juice using polyphenolic profiles and flavonoid content has been achieved and the determination of flavonoids compounds in grapefruit- and orange juice is applied.
169 citations
TL;DR: It is found that 7-hydroxyflavone and apigenin are the most effective aromatase and 17beta-Hydroxysteroid dehydrogenase inhibitors, respectively.
135 citations
TL;DR: Inhibition of 17β-HSORs could lead to an alteration in the availability of the highly active endogenous estrogen, but the effects of these compounds in vivo cannot be predicted on the basis of these results alone.
Abstract: Several flavonoids and isoflavonoids were found to inhibit 17beta-oxidoreduction of estrogens by the purified 17beta-HSOR type 1, or in cell lines expressing 17beta-HSOR type 1 enzyme (T-47D breast cancer cells) or type 2 (PC-3 prostate cancer cells). The structural demands for the inhibition of estrone (E1) reduction and estradiol (E2) oxidation catalyzed by 17beta-HSOR types 1 and 2, respectively, were not identical. Flavones, flavanones, and isoflavones hydroxylated at both the double ring (positions 5 and 7) and ring B (position 4') were the most potent inhibitors of E1 reduction in T-47D cells, and by the purified type 1 enzyme whereas flavones hydroxylated at positions 3, 5, and 7 of rings A and C, with or without a hydroxyl group in ring B, were capable of inhibiting E2 oxidation in PC-3 cells. Change to flavanone structure, or hydroxylation at position 3 of ring C of flavones, or methylation of the hydroxyl group at position 4' of ring B of flavones and isoflavones reduced or abolished their inhibitory activity on E1 reduction in T-47D cells. On the contrary, hydroxyl group at position 3 of flavones (flavonol structure) markedly increased the inhibition of E2 oxidation in PC-3 cells. Thus, changes in the number and location of hydroxyl groups may discriminate inhibition of E1 reduction and E2 oxidation. Some of the differences may be due to differences in pharmacokinetics of these compounds in T-47D and PC-3 cells. Inhibition of 17beta-HSORs could lead to an alteration in the availability of the highly active endogenous estrogen, but the effects of these compounds in vivo cannot be predicted on the basis of these results alone. Some of these compounds (isoflavones) are estrogenic per se, and they may replace endogenous estrogens, whereas flavones are only very weakly estrogenic or nonestrogenic. Regarding prevention or treatment of estrogen-related diseases, apigenin, coumestrol, and genistein raise special interest.
134 citations
TL;DR: The methanolic extract and ethyl acetate-soluble portion from a Brazilian natural medicine, the leaves of Myrcia multiflora DC, were found to show inhibitory activities on aldose reductase and alpha-glucosidase and on the increase of serum glucose level in sucrose-loaded rats and in alloxan-induced diabetic mice.
Abstract: The methanolic extract and ethyl acetate-soluble portion from a Brazilian natural medicine, the leaves of Myrcia multiflora DC., which has been used as a specific medicine against diabetes, were found to show inhibitory activities on aldose reductase and alpha-glucosidase and on the increase of serum glucose level in sucrose-loaded rats and in alloxan-induced diabetic mice. From the ethyl acetate-soluble portion, new flavanone glucosides, myrciacitrins I and II, and new acetophenone glucosides, myrciaphenones A and B, were isolated together with several known compounds such as five flavonol glycosides, myricitrin, mearnsitrin, quercitrin, desmanthin-1, and guaijaverin. The structures of new compounds were determined on the basis of physicochemical and chemical evidence. The principal components of this natural medicine including new glucosides, myrciacitrin I and myrciaphenone B, were found to show potent inhibitory activities on aldose reductase and alpha-glucosidase.
128 citations
TL;DR: In this article, the structures of Artemisia campestris subsp maritima six flavanones, two chromones and the coumarin scopoletin were reported for the first time in this species.
108 citations
TL;DR: In this paper, two new flavanones were isolated from the stem bark of Erythrina burttii and characterised as 5,7-dihydroxy-4-methoxy-3,5′-di-(3-methylbut-2-enyl)flavanone (trivial name, abyssinone V-4′-methyl ether) and 5.
61 citations
TL;DR: Hesperidin dihydrochalcone is an authentic antioxidant drug as tested at all doses and showed a great scavenger activity and/or inhibition of formation on O(2)(-) radicals and a significant scavenging effect on OH radicals as well as an important inhibitory action on non-enzymatic lipid peroxidation.
54 citations
09 Jun 1998
TL;DR: In this article, the main flavonoids present in lemons were characterized and quantified in the wastes and residues obtained during the industrial processing of lemons, and the results showed that lemons contained a 5-fold increase in the concentration of flavonoid glycosides, but some of the hesperidin present in the initial juice was lost.
Abstract: The flavonoids present in the wastes and residues obtained during the industrial processing of lemons were characterized and quantified. Selected products of the juice-extraction line and essential-oil-recovery line were studied. Industrial lemon juice is characterized by containing hesperidin and eriocitrin as the main flavonoid glycosides (130 μg/ml), other minor flavanones and C-glycosylflavones. After the concentration process, the concentrated juice contained a 5-fold increase in the concentration of flavonoids, but some of the hesperidin present in the initial juice was lost. The flavanone glycosides were mainly concentrated in the peel and solid residues, where hesperidin was present as the prevailing flavonoid with concentrations of up to three times higher than those of eriocitrin. In liquid residues eriocitrin was the main flavonoid. The solid residues (peel and frit precipitates) were the most interesting sources for the industrial recovery of flavonoids (13 kg/t processed lemons).
52 citations
TL;DR: A new prenylated 3-hydroxypyranoflavanone, kanzonol Z, was isolated from cultivated licorice and the structure elucidated from spectral evidence, and the stereochemical structure was shown to be ( α R )-3,5′-diprenyl- α,2,4,4′-tetrahydroxydihydrochalcone by Mosher's method.
41 citations
TL;DR: In this paper, the antifungal activity of the CH2Cl2 extract of Monotes engleri Gilg. (Dipterocarpaceae) was investigated in bioautographic TLC assays.
Abstract: The CH2Cl2 extract of Monotes engleri Gilg. (Dipterocarpaceae) showed antifungal activity against the yeast Candida albicans in our bioautographic TLC assays. After a first fractionation of the crude extract, the bioactivity was located in one of the fractions. To perform an efficient targeted isolation of the active compounds, LC/UV/MS and LC/UV/NMR analyses of the crude extract and the active fraction were performed. LC/UV/, LC/MS, and LC/NMR data (1D and 2D) allowed the identification of 1 as (2S)-2,3-dihydro-5,7-dihydroxy–{3-hydroxy-4-[(3-methylbut-2-enyl) oxy]phenyl}-4H-1-benzopyran-4-one, a new prenylated flavanone, named monoteson A. Subsequent isolation of 1 has permitted the determination of its absolute configuration on the basis of CD measurements. Theree other prenylated flavanoes 2–4 were isolated from the same extract. Compound 3 was identified as 2- (3, 5-dihydroxyphenyl) -2,3-dihydro-5, 7-dihydroxy-6, 8-bis (3-methylbut-2-enyl)-4 H-1-benzopyran-4-one, another new natural product, named monotesone B. The structures of 2 and 4 were established as selinone and lonchocarpol A, respectively. The antifungal activity against Candida albicans was determined for all compounds.
TL;DR: It is concluded that all the flavonoids studied inhibit ECOD activity by interfering with the binding of substrate to the active site and other site(s) of the enzyme and that their structural differences lead to different binding affinities at the active sites and possibly to binding at other sites of the enzymes for the Flavonoids.
Abstract: 1. The inhibitory effects of several naturally occurring flavonoids and related compounds on cytochrome P450-dependent 7-ethoxycoumarin O-deethylase (ECOD) and the structure-activity relationships were studied in liver microsomes from rats treated with 3-methylcholanthrene (MC). 2. All the flavonoids (flavone, apigenin, chrysin, flavonol, fisetin, kaempferol, morin, myrisetin, quercetin, flavanone, hesperetin and naringenin) studied inhibited microsomal ECOD activity in the following order: flavones > flavonols > flavanones, were mixed type inhibitors and had Ki in the range of 0.17-4.5 microM. (+/-)-Catechin had no effect. 3. The double bond between C2 and C3 of the C ring, the keto group and hydroxyl group of this ring in the flavonoids seem to play major roles in inhibiting the ECOD activity. 4. The hydroxyl groups in the C5 and C7 positions of A ring in the flavone and the hydroxyl group in the C3 position of C ring in the flavonol classes, respectively, were important factors for the inhibition of the enzyme. 5. In a series of 3, 5, 7-trihydroxyflavones, the hydroxyl group at the C4 in the B ring was also an important factor for the inhibition of ECOD activity, but hydroxyl groups in other positions of the B ring had little effect on the inhibition. 6. We conclude that all the flavonoids studied inhibit ECOD activity by interfering with the binding of substrate to the active site and other site(s) of the enzyme and that their structural differences lead to different binding affinities at the active site and possibly to binding at other site(s) of the enzyme for the flavonoids.
TL;DR: A significant increase in the antifungal effect of the substituted flavones could be observed if mixtures in combination with the unsubstituted flavone or flavanone were used.
TL;DR: In this article, a prenylated flavanone glucoside (sophoraflavanone I 7-O-β-glucopyranoside) and three resveratrol oligomers, stenopyllols A-C, were isolated from the roots of Sophora stenophylla along with six known flavonoids and three known reagent oligomers.
Abstract: A new prenylated flavanone glucoside (sophoraflavanone I 7-O-β-glucopyranoside) and three new resveratrol oligomers, stenopyllols A-C, were isolated from the roots of Sophora (S.) stenophylla along with six known flavonoids and three known resveratrol oligomers. Their structures were determined by spectroscopic analysis of correlation spectroscopy involving long-range coupling and nuclear Overhouser effect experiments.
TL;DR: Dioflorin was isolated as a minor constituent from the rootbark of Dioclea grandiflora and determined to be 5,7,2'-trihydroxy-8-methoxy-6-(3-methyl-2-butenyl)flavanone on the basis of spectral analysis.
Abstract: Dioflorin (1) was isolated as a minor constituent from the rootbark of Dioclea grandiflora, the crude extract of which demonstrated analgesic activity. The structure of 1 has been determined to be 5,7,2'-trihydroxy-8-methoxy-6-(3-methyl-2-butenyl)flavanone on the basis of spectral analysis.
Patent•
04 Dec 1998TL;DR: The use of flavone derivatives and flavanone derivatives, in particular flavonoids for stabilizing cosmetic or dermatologically acceptable substances, was discussed in this paper, where the structural moiety of dibenzoylmethane against the decomposition caused by UV radiation was discussed.
Abstract: Use of flavone derivatives and flavanone derivatives, in particular flavonoids for stabilizing cosmetic or dermatologically acceptable substances, the chemical formula of which includes the structural moiety of dibenzoylmethane, against the decomposition caused by UV radiation.
TL;DR: Four new prenylated flavanones, abyssinone-V 4'-methyl ether (1) and abyssinoflavanones IV (2), V (3), and VI (4), have been isolated from the African medicinal plant, Erythrina abyssinica.
Abstract: Four new prenylated flavanones, abyssinone-V 4'-methyl ether (1) and abyssinoflavanones IV (2), V (3), and VI (4), have been isolated as minor flavanones from the African medicinal plant, Erythrina abyssinica, together with a known flavanone, sigmoidin D. The structure elucidation of compounds 1-4 by spectroscopic studies is described.
TL;DR: In this paper, a 4′- O -sulphated analogue of wedeloside, a new flavanone, 7,4′-dihydroxy-8,3′-dimethoxyflavanone and its related chalcone, together with the 4′ − O -β- d -glucopyranoside of the latter, and a number of known compounds were isolated from the aerial parts of Wedelia asperrima.
TL;DR: From the roots of Amorpha fruticosa, a new prenylated flavanone was isolated, in addition to seven known phenolic compounds as mentioned in this paper, which was confirmed to be 5,7,3,trihydroxy-6,8,5′-triisoprenyl-4′-methoxyflavanone (isoamoritin).
TL;DR: Lonchocarpol A, a flavanone, demonstrates in vitro inhibitory activity against methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecium.
Abstract: Lonchocarpol A, a flavanone, demonstrates in vitro inhibitory activity against methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecium. This activity is antagonized by mouse plasma, which may account for its lack of in vivo activity. This compound demonstrates no differentiation with respect to the inhibition of RNA, DNA, cell wall, and protein synthesis.
TL;DR: Analysis of the structure activity relationship among these novel diarylheptanoids led to the conclusion that the position of attachment of a chalcone or a flavanone to a diaryl heptanoid does not affect their inhibitory potency although their presence in association causes a substantial enhancement of the inhibitory activity.
Abstract: Thirteen novel diarylheptanoids bearing a chalcone or a flavanone moiety (1-13), a new curcumin derivative, 1,2-dihydrobis(de-O-methyl)curcumin (14), and two known flavonoids (15 and 16) isolated from the seeds of Alpinia blepharocalyx K. Schum. were tested for their inhibitory effects on nitric oxide (NO) production in lipopolysaccaride (LPS)-activated murine macrophages J774.1 in vitro. All the tested compounds inhibited NO production in a concentration-dependent manner (IC50=36-568 microM). Among the compounds examined, blepharocalyxin B (13) was the most potent inhibitor of NO production (IC50=36 microM). Analysis of the structure activity relationship among these novel diarylheptanoids led to the conclusion that the position of attachment of a chalcone or a flavanone to a diarylheptanoid does not affect their inhibitory potency although their presence in association causes a substantial enhancement of the inhibitory activity. Moreover, a conjugated double bond in a chalcone moiety potentiated the inhibitory activity. On the other hand, hexamethoxydeoxycalyxin A (17) and pentamethoxycalyxin B (18), a methylated product of calyxin A (1) and an epimeric mixture of calyxin B, showed greatly reduced activity suggesting that phenolic hydroxyl groups are involved in the inhibitory activity.
TL;DR: In this article, the diarylheptanoids having a chalcone or a flavanone moiety were isolated from Alpinia blepharocalyx K. and their structures, including the corrected one of calyxin A (1), were elucidated by spectroscopic methods.
Abstract: Calyxins A (1), E (2) and F (3), 6-hydroxycalyxin F (4), Calyxin G and epicalyxin G (5 and 6), novel diarylheptanoids having a chalcone or a flavanone moiety, were isolated from Alpinia blepharocalyx K. Schum. and their structures, including the corrected one of calyxin A (1), were elucidated by spectroscopic methods.
TL;DR: A study of the phenolic compounds of the closely related papilionoid tribes, Podalyrieae and Liparieae, proved that the flavonoid patterns of hydrolysed seed extracts are remarkably conservative, favouring the opinion that the two tribes should be combined.
Abstract: A study of the phenolic compounds of the closely related papilionoid tribes,Podalyrieae andLiparieae, proved that the flavonoid patterns of hydrolysed seed extracts are remarkably conservative. Butin (7, 3′, 4′-trihydroxyflavanone), 3′-hydroxydaidzein (7, 3′, 4′-trihydroxyisoflavone), vicenin-2 (6, 8-di-β-D-glucopyranosyl-5, 7, 4′-trihydroxyflavone) and orobol (5, 7, 3′, 4′-tetrahydroxyisoflavone) were isolated and identified as the major flavonoids. The seeds ofAmphithalea, Coelidium, Liparia, Xiphotheca, Calpurnia, Stirtonanthus andPodalyria accumulated three isoflavone O-glycosides that yielded 3′-hydroxydaidzein on hydrolysis. In contrast,Virgilia contained a unique combination of vicenin-2 and orobol. Vicenin-2 was also present inCalpurnia as a major compound, butStirtonanthus insignis was the only other species studied that contained orobol (in trace amounts only). Butein, a chalcone, was reported byHarborne from the seed ofCyclopia subternata. This compound's flavanone analog, butin, was the principal component inCyclopia. A cladistic analysis, using flavonoid, alkaloid and morphological data, showed that the seed flavonoids of thePodalyrieae andLiparieae behave rather poorly as cladistic characters. They are, however, of considerable taxonomic value at the tribal level favouring the opinion that the two tribes should be combined. The apparent absence of flavonoids in the seed ofHypocalyptus supports the suggestion that it should be excluded from theLiparieae. Flavonoids also show that theArgyrolobium-group is very different from the tribeCrotalarieae and support the recent transfer of this group to the tribeGenisteae.
TL;DR: In this article, the visnagin cleavage product with O-acetyl-protected glycosyl donor 5a afforded O-glycoside 6a, which could be transformed into the O-benzylprotected compound 6b.
TL;DR: A series of novel flavonoids comprising structural elements present in the antineoplastic agents podophyllotoxin and etoposide was synthesized, finding that oxygen-containing analogues of antiproliferative quinolones moderate cytotoxicity towards L1210 and HT-29 cell lines.
Abstract: A series of novel flavonoids comprising structural elements present in the antineoplastic agents podophyllotoxin and etoposide was synthesized. These oxygen-containing analogues of antiproliferative quinolones exhibited moderate cytotoxicity towards L1210 and HT-29 cell lines.
Patent•
27 Feb 1998TL;DR: In this paper, a composition for accelerating cell differentiation into a fat cell was proposed, consisting of a flavanone in an amount that was effective in accelerating celldifferentiation into fat cells.
Abstract: Provided is a composition for accelerating cell differentiation into a fat cell
comprising a flavanone in an amount effective for accelerating cell
differentiation into a fat cell. Said flavanone can, furthermore, be used for the
preparation of a composition for the activation of sugar or lipid metabolism, and,
consequently, for the improvement or the prevention of diseases such as
diabetes, hyperlipemia and the like.
Patent•
24 Feb 1998TL;DR: Use of a flavone (IA), flavanone (IB) and/or flavonoid (IC) to protect ascorbic acid or ascorbyl compounds against oxidation, including photo-oxidation is claimed as discussed by the authors.
Abstract: Use of a flavone (IA), flavanone (IB) and/or flavonoid (IC) to protect ascorbic acid or ascorbyl compounds against oxidation, including photo-oxidation is claimed.
TL;DR: The relative and absolute stereochemistries of (+)-purpurin (3), a flavanone natural product from Tephrosia, were determined to be 2S,7aR,10S,10aS by synthesis from semiglabrin in conjunction with X-ray crystallographic analysis.
Abstract: The relative and absolute stereochemistries of (+)-purpurin (3), a flavanone natural product from Tephrosia, were determined to be 2S,7aR,10S,10aS by synthesis from semiglabrin in conjunction with X-ray crystallographic analysis.
TL;DR: In this article, the effects of the C-ring heteroatoms on the 13C NMR chemical shifts of the ringexpanded products were found to be of diagnostic value in distinguishing the isomeric products from one another and from the corresponding precursors.
Abstract: 13C NMR spectra of 1,4- and 1,5-benzoheterazepinones and their tetrazolo derivatives, prepared by the Schmidt rearrangement of flavanone analogues, are reported. The effects of the C-ring heteroatoms on the 13C NMR chemical shifts of the ring-expanded products were found to be of diagnostic value in distinguishing the isomeric products from one another and from the corresponding precursors. © 1998 John Wiley & Sons, Ltd.