Comparative studies on interactions of baicalein, baicalin and scutellarin with lysozyme

• Published in: European journal of medicinal chemistry Vol. 46; no. 12; pp. 6039 - 6045
• Main Authors: Huang, Yun, Cui, Li-Jian, Wang, Jian-Ming, Huo, Kun, Chen, Chen, Zhan, Wen-Hong, Dou, Yu-Hong
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Masson SAS 01.12.2011; Elsevier
• Subjects: Animals; Anti-Infective Agents - pharmacology; Antibacterial agents; Antibiotics. Antiinfectious agents. Antiparasitic agents; Apigenin - pharmacology; Baicalein; Baicalin; Biological and medical sciences; Chickens; Enzyme Inhibitors - pharmacology; Flavanones - pharmacology; Flavonoids - pharmacology; Fluorescence spectroscopy; General pharmacology; Glucuronates - pharmacology; Lysozyme; Medical sciences; Muramidase - metabolism; Pantothenic acid; Pantothenic Acid - pharmacology; Pharmacognosy. Homeopathy. Health food; Pharmacology. Drug treatments; Protein Binding; Scutellarin; Spectrometry, Fluorescence; Scutellarin; Fluorescence spectroscopy; Baicalein; Baicalin; Lysozyme; Pantothenic acid; Enzyme; Molecular interaction; Stability constant; Flavonoid; Fluorescence spectrometry; Glycosylases; Glycosidases; Uronic acid; Flavone derivatives; Hydrolases; Glycoside; Antibacterial agent; Pharmacokinetics; Thermodynamic properties; Comparative study
• ISSN: 0223-5234; 1768-3254
• DOI: 10.1016/j.ejmech.2011.10.016

The interactions of baicalein, baicalin and scutellarin with lysozyme (LYSO) were studied by fluorescence and UV spectroscopy. The results showed that all the three flavones can quench the fluorescence of LYSO via static quenching with the distance between the donor and acceptor less than 7 nm. The hydroxyl at B-ring gave flavones an advantage to binding with LYSO. Electrostatic forces played a major role in stabilizing baicalein–LYSO complex and baicalin–LYSO complex, whereas hydrophobic interactions in scutellarin–LYSO. Furthermore, the presence of pantothenic acid can increase the binding constant and the number of binding sites between flavones and LYSO. Contour spectra of (a) LYSO, (b) Baicalein–LYSO, (c) Baicalin–LYSO, and (d) Scutellarin–LYSO; C  (LYSO) = 1.0 × 10 −6 M, C (Baicalein) = C (Baicalin) = C (Scutellarin) = 7.0 × 10 −6 M. Peak 1 is the Rayleigh scattering peak ( λ ex = λ em), peak 2 mainly reveals the spectral behavior of Trp residues, and peak 3 the fluorescence characteristic of polypeptide backbone structures. In the presence of baicalein, Trp residues were located in a more hydrophobic environment, while Trp residues were brought to a more hydrophilic environment in the presence of baicalin or scutellarin. The three flavones can change polarity of hydrophobic cavity, thereby influencing the conformation of LYSO. [Display omitted] ► The paper showed the effect of pantothenic acid on flavone–LYSO binding. ► The flavones quenched LYSO fluorescence via static quenching with r less than 7 nm. ► The hydroxyl and steric hindrance of flavones influenced the binding interactions. ► Pantothenic acid decreased K a and n of the flavones to LYSO. ► It provided a support for activity of antibiotics enhanced by pantothenic acid.