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.
Antioxidant flavonoids from Alhagi maurorum
Ahmad, Saeed,Riaz, Naheed,Saleem, Muhammad,Jabbar, Abdul,Nisar-Ur-Rehman,Ashraf, Mohammad
, p. 138 - 143 (2010)
A new flavonoid, isorhamnetin-3-O-[-α-L-rhamnopyranosyl-(1→3)]- β-D-glucopyranoside (1), along with two known flavonoids 3′-O-methylorobol (2) and quercetin 3-O-β-D-glucopyranoside (3), was isolated from Alhagi maurorum. Their structures were established with the help of mass spectrometry, 1D and 2D NMR spectroscopy, and in comparison with the literature data. Compounds 1 and 2 exhibited moderate antioxidant activity in the 2,2-diphenyl-1-picrylhydrazyl free radical scavenging assay.
Antioxidant effects of isorhamnetin 3,7-di-O-β-D-glucopyranoside isolated from mustard leaf (Brassica juncea) in rats with streptozotocin-induced diabetes
Yokozawa, Takako,Kim, Hyun Young,Cho, Eun Ju,Choi, Jae Sue,Chung, Hae Young
, p. 5490 - 5495 (2002)
To investigate the effects of isorhamnetin 3,7-di-O-β-D-glucopyranoside (isorhamnetin diglucoside), a major flavonoid compound of mustard leaf, on oxidative stress due to diabetes mellitus, in vivo and in vitro studies were carried out. Oral administration of isorhamnetin diglucoside (10 or 20 mg/kg of body weight/day for 10 days) to rats with streptozotocin-induced diabetes significantly reduced serum levels of glucose and 5-(hydroxymethyl)furfural (5-HMF), which is glycosylated with hemoglobin and is an indicator of oxidative stress. After intraperitoneal administration, isorhamnetin diglucoside did not show these activities. In addition, after oral administration, the thiobarbituric acid-reactive substance levels of serum, and liver and kidney mitochondria declined significantly compared with the control group in a dose-dependent manner, whereas after intraperitoneal administration these levels fell only slightly. On the basis of the oral and intraperitoneal results, it was hypothesized that isorhamnetin diglucoside was converted to its metabolite in vivo, and its conversion to its aglycone, isorhamnetin, by β-glucosidase was confirmed; isorhamnetin acted as an antioxidant. Moreover, it was observed that isorhamnetin diglucoside had no effect on the 1,1-diphenyl-2-picrylhydrazyl radical, whereas isorhamnetin showed a potent antioxidant effect in vitro. In addition, intraperitoneal administration of isorhamnetin reduced serum glucose and 5-HMF levels. Furthermore, lipid peroxidation in blood, liver, and kidney associated with diabetes mellitus declined after the administration of isorhamnetin. These results suggest that isorhamnetin diglucoside is metabolized in vivo by intestinal bacteria to isorhamnetin and that isorhamnetin plays an important role as an antioxidant.
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
A new isorhamnetin glycoside and other phenolic compounds from Callianthemum taipaicum
Wang, Dong-Mei,Pu, Wen-Jun,Wang, Yong-Hong,Zhang, Yu-Juan,Wang, Shan-Shan
, p. 4595 - 4603 (2012)
A new flavonol glycoside together with five known phenolic compounds were isolated from the whole herb of Callianthemum taipaicum. The compounds were identified as isorhamnetin-3-O-α-L-arabinoside-7-O-β-D-glucoside (1), isorhamnetin-3-O-β-D-glucoside (2), dibutyl phthalate (3), (+)-1-hydroxylpinoresinol-4'-β-D-glucoside (4), pinoresinol-4'-O-β-D- glucoside (5) and 2-phenylethyl-β-primeveroside (6). Compound 1 was identified as a new flavonol glycoside. The compound 6 was isolated for the first time as natural product. All compounds were isolated for the first time from the Callianthemum genus. Furthermore, the 2D-NMR data of the four known compounds 2-5 are given for the first time in this paper. All the structures were identified on the basis of detailed spectral analysis. The compounds 1 and 4 exhibited certain antifungal activity.
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.
Isolation, characterization, complete structural assignment, and anticancer activities of the methoxylated flavonoids from rhamnus disperma roots
Abd El-Wahab, Mohammed F.,Abdalla, Ashraf N.,Mohammed, Abd El-Salam I.,Mohammed, Hamdoon A.,Ragab, Ehab A.,Shaheen, Usama
, (2021/10/01)
Different chromatographic methods including reversed-phase HPLC led to the isolation and purification of three O-methylated flavonoids; 5,4’-dihydroxy-3,6,7-tri-O-methyl flavone (penduletin) (1), 5,3’-dihydroxy-3,6,7,4’,5’-penta-O-methyl flavone (2), and 5-hydroxy-3,6,7,3’,4’,5’-hexa-O-methyl flavone (3) from Rhamnus disperma roots. Additionlly, four flavonoid glycosides; kampferol 7-O-α-L-rhamnopyranoside (4), isorhamnetin-3-O-β-D-glucopyranoside (5), quercetin 7-O-α-L-rhamnopyranoside (6), and kampferol 3, 7-di-O-α-L-rhamnopyranoside (7) along with benzyl-O-β-D-glucopyranoside (8) were successfully isolated. Complete structure characterization of these compounds was assigned based on NMR spectroscopic data, MS analyses, and comparison with the literature. The O-methyl protons and carbons of the three O-methylated flavonoids (1–3) were unambiguously assigned based on 2D NMR data. The occurrence of compounds 1, 4, 5, and 8 in Rhamnus disperma is was reported here for the first time. Compound 3 was acetylated at 5-OH position to give 5-O-acetyl-3,6,7,3’,4’,5’-hexa-O-methyl flavone (9). Compound 1 exhibited the highest cytotoxic activity against MCF 7, A2780, and HT29 cancer cell lines with IC50 values at 2.17 μM, 0.53 μM, and 2.16 μM, respectively, and was 2–9 folds more selective against tested cancer cell lines compared to the normal human fetal lung fibroblasts (MRC5). It also doubled MCF 7 apoptotic populations and caused G1 cell cycle arrest. The acetylated compound 9 exhibited cytotoxic activity against MCF 7 and HT29 cancer cell lines with IC50 values at 2.19 μM and 3.18 μM, respectively, and was 6–8 folds more cytotoxic to tested cancer cell lines compared to the MRC5 cells.
Synthesis of Flavonols via Pyrrolidine Catalysis: Origins of the Selectivity for Flavonol versus Aurone
Xiong, Wei,Wang, Xiaohong,Shen, Xianyan,Hu, Cuifang,Wang, Xin,Wang, Fei,Zhang, Guolin,Wang, Chun
, p. 13160 - 13176 (2020/11/23)
A novel synthetic method for flavonol from 2′-hydroxyl acetophenone and benzaldehyde promoted by pyrrolidine under an aerobic condition in water is established. This protocol was supported by efficient synthesis of 44 common examples and three natural products. The α, β-unsaturated iminium ion (enimine ion E) was proved to be the key intermediate in the reaction. H218O and 18O2 isotope tracking experiments demonstrated that both water and the aerobic atmosphere were necessary to ensure the transformation. The selectivity for flavonol or aurone was originated from solvent-triggered intermediates, which were determined by UV-visible spectra from isolated enimine. The phenol-iminium E-A is dominant in water and the ketoenamine intermediate E-B is prevalent in acetonitrile. In the presence of pyrrolidine and oxygen, E-A leads to flavonol through E-I, a zwitterionic-like phenoloxyl-iminium ion, following the key steps of cyclization and a [2 + 2] oxidation; E-B proceeds through path II, a radical process induced by photolysis of E-B with both pyrrolidine and oxygen, to afford aurone. Preliminary mechanistic studies are reported.
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.
Characterization of a Flavonoid 3’/5’/7-O-Methyltransferase from Citrus reticulata and Evaluation of the in Vitro Cytotoxicity of Its Methylated Products
Liu, Xiaojuan,Wang, Yue,Chen, Yezhi,Xu, Shuting,Gong, Qin,Zhao, Chenning,Cao, Jinping,Sun, Chongde
, (2020/02/25)
O-methylation of flavonoids is an important modification reaction that occurs in plants. O-methylation contributes to the structural diversity of flavonoids, which have several biological and pharmacological functions. In this study, an O-methyltransferase gene (CrOMT2) was isolated from the fruit peel of Citrus reticulata, which encoding a multifunctional O-methyltransferase and could effectively catalyze the methylation of 3’-, 5’-, and 7-OH of flavonoids with vicinal hydroxyl substitutions. Substrate preference assays indicated that this recombinant enzyme favored polymethoxylated flavones (PMF)-type substrates in vitro, thereby providing biochemical evidence for the potential role of the enzyme in plants. Additionally, the cytotoxicity of the methylated products from the enzymatic catalytic reaction was evaluated in vitro using human gastric cell lines SGC-7901 and BGC-823. The results showed that the in vitro cytotoxicity of the flavonoids with the unsaturated C2-C3 bond was increased after being methylated at position 3’. These combined results provide biochemical insight regarding CrOMT2 in vitro and indicate the in vitro cytotoxicity of the products methylated by its catalytic reaction.
