480-19-3Relevant articles and documents
Flavonoid glycosides from seeds of Hippophae rhamnoides subsp. Sinensis with α-glucosidase inhibition activity
Li, Rui,Wang, Qing,Zhao, Menghao,Yang, Peiming,Hu, Xiao,Ouyang, Danwei
, (2019)
Hippophae rhamnoides subsp. Sinensis is a famous traditional medicinal plant in Tibet and Mongolia of China. Three novel flavonoid glycosides and ten known analogues were obtained from the seeds of H. rhamnoides. The structures of new compounds were elucidated by spectroscopics, chemical methods as well as literature data. In vitro assay, compounds 5–9, kaempferol and 70% ethanolic elution fraction showed prominent α-glucosidase inhibitory activities with IC50 values ranging from 8.30 to 112.11 μM, better than that of the positive control, acarbose, whose IC50 value was 1727.07 μM.
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Tsepkova et al.
, (1972)
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Two new flavonol glycosides and biological activities of Diplotaxis harra (Forssk.) Boiss.
Kassem, Mona E.S.,Afifi, Manal S.,Marzouk, Mona M.,Mostafa, Manal A.
, p. 2272 - 2280 (2013)
Two new flavonol glycosides, isorhamnetin 3-O-β-glucopyranoside- 4′-O-β-xylopyranoside (1) and kaempferol 3-O-β-glucopyranoside -4′-O-β-xylopyranoside (2), were isolated from the defatted aqueous methanol extract of the whole plant Diplotaxis harra along with 12 known flavonols (3-14). They were characterised by chemical and spectral methods. The 70% aqueous methanol, chloroform and defatted aqueous methanol plant extracts exhibited significant antioxidant effects (nitroblue tetrazolium reduction method). Their cytotoxic activity was carried out against 11 tumour cell lines (sulphorhodamine B assay). The three extracts expressed the greatest antiproliferative activity against colon 38, P388 and MKN-28 with GI50 (0.45, 0.4, 0.07 g/mL) and against P388 [3-(4,5-dimethylthiazol-2yl)-2,5- diphenyltetrazolium bromide assay] with IC50 (0.26, 0.24, 0.25 g/mL), respectively. The chloroform extract showed the highest activity as eukaryotic DNA topoisomerase II inhibitors of P388 with IC50 0.24 g/mL. Antiviral screening of the extracts and the pure compounds against foot-and-mouth disease virus types A and O revealed a prominent inhibition of its cytopathic effect. 2013
FLAVONOL GLYCOSIDES FROM SEDUM ACRE
Wolbis, Maria,Krolikowska, Maria
, p. 3941 - 3944 (1988)
Three new flavonol glycosides, isohamnetin 3-(2''-acetyl) glucoside, limocitrin 7-glucoside, and limocitrin 3,7-diglucoside were isolated from the aerial parts of Sedum acre.The known compounds quercetin, isohamnetin and their 3- and 3,7-di-glucosides, isohamnetin-7-glucoside an d limocitrin and its 3-glucoside were also identified.The structure of the compounds was determined by means of spectroscopic and chemical methods.
Influence of Substrate Binding Residues on the Substrate Scope and Regioselectivity of a Plant O-Methyltransferase against Flavonoids
Tang, Qingyun,Vianney, Yoanes M.,Weisz, Klaus,Grathwol, Christoph W.,Link, Andreas,Bornscheuer, Uwe T.,Pavlidis, Ioannis V.
, p. 3721 - 3727 (2020/06/02)
Methylation of free hydroxyl groups is an important modification for flavonoids. It not only greatly increases absorption and oral bioavailability of flavonoids, but also brings new biological activities. Flavonoid methylation is usually achieved by a specific group of plant O-methyltransferases (OMTs) which typically exhibit high substrate specificity. Here we investigated the effect of several residues in the binding pocket of the Clarkia breweri isoeugenol OMT on the substrate scope and regioselectivity against flavonoids. The mutation T133M, identified as reported in our previous publication, increased the activity of the enzyme against several flavonoids, namely eriodictyol, naringenin, luteolin, quercetin and even the isoflavonoid genistein, while a reduced set of amino acids at positions 322 and 326 affected both, the activity and the regioselectivity of the methyltranferase. On the basis of this work, methylated flavonoids that are rare in nature were produced in high purity.
Glucuronidation of Methylated Quercetin Derivatives: Chemical and Biochemical Approaches
Docampo-Palacios, Maite L.,Alvarez-Hernández, Anislay,Adiji, Olubu,Gamiotea-Turro, Daylin,Valerino-Diaz, Alexander B.,Viegas, Luís P.,Ndukwe, Ikenna E.,De Fátima, ?ngelo,Heiss, Christian,Azadi, Parastoo,Pasinetti, Giulio M.,Dixon, Richard A.
, p. 14790 - 14807 (2020/12/23)
Botanical supplements derived from grapes are functional in animal model systems for the amelioration of neurological conditions, including cognitive impairment. Rats fed with grape extracts accumulate 3′-O-methyl-quercetin-3-O-β-d-glucuronide (3) in their brains, suggesting 3 as a potential therapeutic agent. To develop methods for the synthesis of 3 and the related 4′-O-methyl-quercetin-7-O-β-d-glucuronide (4), 3-O-methyl-quercetin-3′-O-β-d-glucuronide (5), and 4′-O-methyl-quercetin-3′-O-β-d-glucuronide (6), which are not found in the brain, we have evaluated both enzymatic semisynthesis and full chemical synthetic approaches. Biocatalysis by mammalian UDP-glucuronosyltransferases generated multiple glucuronidated products from 4′-O-methylquercetin, and is not cost-effective. Chemical synthetic methods, on the other hand, provided good results; 3, 5, and 6 were obtained in six steps at 12, 18, and 30% overall yield, respectively, while 4 was synthesized in five steps at 34% overall yield. A mechanistic study on the unexpected regioselectivity observed in the quercetin glucuronide synthetic steps is also presented.