ovalbumin and isoquercitrin

This research firstly investigated the inhibitory effect of isoquercitrin (ISQ) on Ovalbumin (OVA) glycation. The mechanism was elucidated through the interaction between OVA and ISQ, and changes in glycation sites and degree of each site as deduced by spectroscopy, spectrometry and molecular docking. ISQ significantly inhibited OVA glycation by attenuating the conformational change induced by glycation. It quenched the fluorescence of Trp via static mechanism, and exposed Trp residues to a more hydrophobic surroundings. Formation of OVA-ISQ complex was a endothermic processing driven by hydrophobic interactions, van der Waals forces and hydrogen bonds. LC-Orbitrap-MS/MS revealed that ISQ altered the location of glycation and alleviated the glycation degree of most sites. Molecular docking results indicated that ISQ inserted into the hydrophobic pocket of OVA with six hydrogen bonds and one π-π stacking formed between ISQ and the amino acid residues of OVA, leading to the altered glycation activity of some sites.

Topics: Binding Sites; Chromatography, High Pressure Liquid; Glycosylation; Hydrogen Bonding; Hydrophobic and Hydrophilic Interactions; Molecular Docking Simulation; Ovalbumin; Peptides; Protein Binding; Quercetin; Spectrometry, Fluorescence; Tandem Mass Spectrometry; Thermodynamics

Argemone platyceras is used in Mexico as a remedy for cough, bronchitis and pneumonia. The present study was performed to investigate the pharmacological anti-asthmatic properties of Argemone platyceras on airways and to identify its active principles. Methanol extracts of leaves and flowers, subsequent organic and aqueous extraction phases, and silica gel chromatography fractions were assayed on the carbachol-induced response, and/or on ovalbumin antigenic challenge, and on leukotriene D(4)-induced response of tracheae from sensitized and non-sensitized guinea-pigs. Methanol extracts, ethyl-acetate phase, and its fractions 6 and 7 inhibited the carbachol-induced contractile response. Isoquercitrin and rutin were the main compounds found in fractions 6 and 7 respectively. Isoquercitrin (fraction 6) abolished the response to ovalbumin, and decreased the contractile response to leukotriene D(4). Because of its effect on carbachol-induced contractile response, on the late-phase response to ovalbumin, and on leukotriene D(4)-induced contractile response, isoquercitrin might be highly useful in treatment of asthma.

Topics: Acetates; Animals; Anti-Asthmatic Agents; Anti-Inflammatory Agents, Non-Steroidal; Argemone; Asthma; Bronchoconstriction; Carbachol; Chemical Fractionation; Dose-Response Relationship, Drug; Flowers; Guinea Pigs; Indomethacin; Leukotriene D4; Magnetic Resonance Spectroscopy; Male; Methanol; Molecular Structure; Muscle Contraction; Ovalbumin; Phytotherapy; Plant Leaves; Quercetin; Rutin; Time Factors; Trachea