Unveiling interaction mechanisms between myricitrin and human serum albumin: Insights from multi-spectroscopic, molecular docking and molecular dynamic simulation analyses.

Myricitrin is a natural polyhydroxy flavonoid and is mainly derived from the bark and leaves of the Chinese Bayberry tree (Myrica rubra). It has different pharmacological activities, including antioxidative, anti-inflammatory, hypoglycemic, antiviral, liver protection and cholagogue properties, and may be added to foods, pharmaceuticals, and cosmetic products for antioxidant purposes. In this study, the interaction mechanism between myricitrin and human serum albumin (HSA) was investigated using spectroscopic methods, molecular docking techniques, and molecular dynamic simulations. We showed that the HSA/myricitrin interaction exhibited a static fluorescence quenching mechanism, and that binding processes were spontaneous in nature, with the main forces exemplified by hydrogen bonding, hydrophobic interactions, and electrostatic interactions. Fluorescence spectroscopy, ultraviolet-visible (UV-vis) spectroscopy, synchronous fluorescence spectroscopy, three-dimensional (3D) fluorescence spectroscopy, micro-Fourier transform infrared spectroscopy (micro-FTIR), and circular dichroism (CD) spectroscopy showed that myricitrin binding altered the HSA conformation to some extent. Competitive binding and molecular docking studies showed that the preferred binding of myricitrin on HSA was in the sub-structural domain IIA (Site I); molecular dynamic simulations revealed that myricitrin interacted with HSA to produce a well stabilized complex, and it also generated a conformational change in HSA. The antioxidant capacity of the HSA-myricitrin complex was reduced when compared with free myricitrin. The identification of HSA-myricitrin binding mechanisms provides valuable insights for the application of myricitrin to the food and pharmaceutical industries.

Molecular Insight into the Binding of Astilbin with Human Serum Albumin and Its Effect on Antioxidant Characteristics of Astilbin.

Astilbin is a dihydroflavonol glycoside identified in many natural plants and functional food with promising biological activities which is used as an antioxidant in the pharmaceutical and food fields. This work investigated the interaction between astilbin and human serum albumin (HSA) and their effects on the antioxidant activity of astilbin by multi-spectroscopic and molecular modeling studies. The experimental results show that astilbin quenches the fluorescence emission of HSA through a static quenching mechanism. Astilbin and HSA prefer to bind at the Site Ⅰ position, which is mainly maintained by electrostatic force, hydrophobic and hydrogen bonding interactions. Multi-spectroscopic and MD results indicate that the secondary structure of HSA could be changed because of the interaction of astilbin with HSA. DPPH radical scavenging assay shows that the presence of HSA reduces the antioxidant capacity of astilbin. The explication of astilbin-HSA binding mechanism will provide insights into clinical use and resource development of astilbin in food and pharmaceutical industries.

Lamiophlomis herba: A comprehensive overview of its chemical constituents, pharmacology, clinical applications, and quality control.

Lamiophlomis rotata (Benth.) Kudo (LR) is an extensively used Chinese herbal medicine. It contains a variety of chemical constituents with significant biological activities that were first recorded in the classical masterpiece of Tibetan Medicine, Somaratsa. In this review, we summarize the information regarding the traditional uses, chemical constituents, pharmacological effects, clinical applications, quality control, toxicology, and pharmacokinetics of LR. At least 223 chemical constituents have been isolated from LR, including phenylethanoid glycosides, flavonoids, iridoids, volatile oils, et al. Their various physiological activities have been demonstrated as analgesic, hemostatic, anti-inflammatory, anti-tumor, marrow-supplementing, anti-bacterial, and immunity-strengthening. The clinical applications of LR and quality control are also discussed, as well as some existing problems. This article aims to provide more comprehensive information on the chemical composition, pharmacological activity, and clinical application of LR, so as to provide a theoretical basis for the further reasonable development of LR in clinical practice and of new drugs.