Biotransformation of paeonol by Panax ginseng root and cell cultures

Incorporating pH/NIR responsive nanocontainers into a smart self-healing coating for a magnesium alloy with controlled drug release, bacteria killing and osteogenesis properties

Magnesium (Mg)-based orthopedic implant materials can potentially be protected from deterioration using a protective polymer coating. However, this coating is susceptible to excessive corrosion and accidental scratches. Moreover, the inadequate bone integration and infections associated with bone implants present additional challenges that hinder their effective use. In this work, a spin-spray layer-by-layer (SSLbL) assembly technique was employed to develop a smart self-healing coating for Mg alloy WE43. This coating was based on paeonol-encapsulated nanocontainers (PMP) that were modified with a stimuli-responsive polydopamine (PDA). The leached paeonol could form a compact chelating layer when complexed with Mg2+ ions. Dynamic reversible hydrogen bonds were formed between assembly units, which ensured that the hybrid coating possessed rapid and cyclic self-healing properties. Under 808 nm near-infrared (NIR) laser irradiation, the self-healing coating exhibited antibacterial properties due to the synergistic effects of hyperthermia, reactive oxygen species (ROS), and paeonol. In addition, the incorporation of nanoparticles into the hybrid coating led to improvements in the cytocompatibility and osteogenic properties of the implant material. The smart coating enhanced alkaline phosphatase activity, extracellular matrix (ECM) mineralization, and the expression of osteogenic genes. This study presents a promising opportunity to explore the application of a smart self-healing coating for a Mg alloy. STATEMENT OF SIGNIFICANCE: Herein, we report a self-healing coating comprised of polyethyleneimine and nanocontainer-crosslinked hyaluronic acid to achieve drug-controlled release, antimicrobial activity, and osteogenesis performance. The formation of hydrogen bonds between HA and PEI facilitated the self-assembly process, thereby improving the coating's corrosion resistance and adhesion strength. The hybrid coating exhibited a rapid and cyclic self-healing activity due to paeonol and dynamic reversible bonds. The release of paeonol was controlled by pH and NIR stimuli owing to polydopamine modification. In vitro testing revealed that the hybrid coating achieved effective bacteria eradication through synergistic effects of hyperthermia, reactive oxygen species, and paeonol. Moreover, the smart coating was found to enhance alkaline phosphatase activity, extracellular matrix mineralization, and the expression of osteogenic genes.

Paeonol Derivatives and Pharmacological Activities: A Review of Recent Progress

Paeonol, 2-hydroxy-4-methoxy acetophenone, is one of the main active ingredients of traditional Chinese medicine such as Cynanchum paniculatum, Paeonia suffruticosa Andr and Paeonia lactiflora Pall. Modern medical research has shown that paeonol has a wide range of pharmacological activities. In recent years, a large number of studies have been carried out on the structure modification of paeonol and the mechanism of action of paeonol derivatives has been studied. Some paeonol derivatives exhibit good pharmacological activities in terms of antibacterial, anti-inflammatory, antipyretic analgesic, antioxidant and other pharmacological effects. Herein, the research progress on paeonol derivatives and their pharmacological activities were systematically reviewed.

Enzymic synthesis of gastrodin through microbial transformation and purification of gastrodin biosynthesis enzyme

Gastrodin, a major bioactive component of a famous Chinese herb Gastrodia elata B1., has diverse pharmaceutical functions. It is usually obtained by extraction from a plant or through chemical synthesis. However, traditional extraction from Gastrodia elata B1. is time and money consuming, while chemical synthesis is a complicated procedure and always leads to very serious environmental pollution. Thus it is urgent to explore a new gastrodin source which is more economical and environmental. The present study reports a novel approach to the production of gastrodin through biosynthesis and microbial transformation. Rhizopus chinensis SAITO AS3.1165 was screened from about 50 fungal and bacterial strains and found capable of biotransforming p-hydroxybenzaldehyde into gastrodin for use in gastrodin production. A series of purification steps including (NH(4))(2)SO(4) precipitation, ion exchange chromatography and gel filtration column chromatography was successfully used for purification of the gastrodin biosynthesis enzyme (GBE). The purity of GBE was above 95% and its molecular weight was about 63.2 kDa. We further characterized GBE's function condition, and found that the optimal temperature was 50 °C and the optimum pH 6.0. The enzyme was stable at a temperature lower than 50 °C and a pH between 6.0 and 9.0. The result indicated that gastrodin could be successfully synthesized by microbial transformation, providing a new approach for gastrodin production.