rhamnetin and kaempferol

This study is aimed at determining the relationship of flavonoid structures to their chemical and intracellular antioxidant activities. The antioxidant activities of 60 flavonoids were investigated by three different antioxidant assays, including 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, oxygen radical absorption capacity (ORAC), and cellular antioxidant activity (CAA) assays. The result showed 6 flavonoids as good cellular antioxidants evaluated for the first time. The cellular antioxidant activities of compounds 7-methoxy-quercetin, 3-

Topics: Antioxidants; Catalase; Cell Proliferation; Flavonoids; Hep G2 Cells; Humans; Kaempferols; Quercetin; Structure-Activity Relationship; Superoxide Dismutase; Up-Regulation

Three new flavonoid glycosides-soyaflavonosides A (1), B (2), and C (3)-together with 23 known ones were obtained from the 70% EtOH extract of Flos Sophorae (Sophora japonica, Leguminosae). Their structures were elucidated by chemical and spectroscopic methods. Among the known isolates, 14, 18, 20, 22, and 26 were isolated from the Sophora genus for the first time; 12, 19, 24, and 25 were obtained from the species firstly. Moreover, NMR data for compounds 18 and 26 are reported for the first time here. Meanwhile, compounds 4, 8-13, 15, 16, 19, 21, and 22 presented obvious inhibitory effects on TG accumulation in HepG2 cells. Analysis of the structure-activity relationship indicated that all of the quercetin glycosides examined in this study possess significant activity that is not significantly influenced by the amount of glycosyl present, whereas increasing the amount of glycosyl reduced the activities of isorhamnetin glycosides and orobol. In addition, a high dose (30 μmol/l) of kaempferol was found to inhibit HepG2 cell growth, while a low dose (10 μmol/l) was observed to decrease TG accumulation.

Topics: Cell Proliferation; Flavonoids; Flowers; Glycosides; Hep G2 Cells; Hormesis; Humans; Kaempferols; Plant Extracts; Quercetin; Rutin; Sophora; Structure-Activity Relationship; Triglycerides

Quantitative parameters for interaction of flavonoids-the naturally occurring antioxidants, with solvents and surfactants are determined using UV-visible absorption spectroscopy. The availability of flavonoids; kaempferol, apigenin, kaempferide and rhamnetin in micelles of sodium dodecyl sulfate (SDS) is reflected in terms of partition coefficient, K(c). Thermodynamic calculations show that the process of transfer of flavonoid molecules to anionic micelles of SDS is energy efficient. A distortion in flavonoid's morphology occurs in case of kaempferol and apigenin in surfactant and water, exhibited in terms of a new band in the UV region of electronic spectra of these flavonoids. The partition coefficients of structurally related flavonoids are correlated with their antioxidant activities.

Topics: Antioxidants; Apigenin; Flavonoids; Kaempferols; Methanol; Micelles; Quercetin; Sodium Dodecyl Sulfate; Solubility; Solutions; Spectrophotometry, Ultraviolet; Spectrum Analysis; Temperature; Thermodynamics; Water

Preliminary studies with the four extracts of Oxytropis falcate Bunge exhibited that the chloroform and ethyl acetate extracts showed stronger antibacterial activities against the nine tested Gram-positive and Gram-negative bacteria. The HPLC-scanned and bioassay-guided fractionation led to the isolation and identification of the main flavonoid compounds, i.e. rhamnocitrin, kaempferol, rhamnetin, 2',4'-dihydroxychalcone and 2',4',beta-trihydroxy-dihydrochalcon. Except 2',4',beta-trihydroxy-dihydrochalcon, four other compounds had good antibacterial activities. The minimal inhibitory concentrations (MICs) and minimal bactericidal concentrations (MBCs) of the four compounds ranged between 125 and 515 microg mL(-1). Staphylococcus aureus was the most susceptible to these compounds, with MIC and MBC values from 125 to 130 microg mL(-1). This is the first report of antibacterial activity in O. falcate Bunge. In this study, evidence to evaluate the biological functions of O. falcate Bunge is provided, which promote the rational use of this herb.

Topics: Anti-Bacterial Agents; Bacteria; Chalcone; Chromatography, High Pressure Liquid; Flavonoids; Kaempferols; Microbial Sensitivity Tests; Oxytropis; Plant Extracts; Quercetin

To study the chemical constituents of Myricaria bracteata.. The chemical constituents were isolated by silica gel column chromatography and the structures were elucidated by spectroscopic methods.. Eleven compounds were obtained and identified as rhamnetin, 3,5,4'-trihydroxy-7,3'-dimethoxyflavone, 3,5,4'-trihydroxy-7-methoxyflavone, quercetin-3-O-alpha-L-rhamnopyranoside, kaempferol, quercetin, chrysoerio, gallic acid, gallic acid ethylester, beta-sitosterol, daucosterol.. All compounds were obtained from M. bracteata for the first time.

Topics: Flavones; Flavonoids; Glycosides; Kaempferols; Monosaccharides; Plants, Medicinal; Quercetin; Tamaricaceae