How procyanidin C1 sticks to collagen: The role of proline rings

Thermosensitive Porcine Myocardial Extracellular Matrix Hydrogel Coupled with Proanthocyanidins for Cardiac Tissue Engineering

Currently, there are no therapies that prevent the negative myocardial remodeling process that occurs after a heart attack. Injectable hydrogels are a treatment option because they may replace the damaged extracellular matrix and, in addition, can be administered minimally invasively. Reactive oxygen species generated by ischemia-reperfusion damage can limit the therapeutic efficacy of injectable hydrogels. In order to overcome this limitation, grape seed proanthocyanidins were incorporated as antioxidant compounds into a thermosensitive myocardial extracellular matrix hydrogel in this study. For the fabrication of the hydrogel, the extracellular matrix obtained by decellularization of porcine myocardium was solubilized through enzymatic digestion, and the proanthocyanidins were incorporated. After exposing this extracellular matrix solution to 37 °C, it self-assembled into a hydrogel with a porous structure. According to the physicochemical and biological evaluation, the coupling of proanthocyanidins in the hydrogel has a positive effect on the antioxidant capacity, gelation kinetics, in vitro degradation, and cardiomyocyte viability, indicating that the hydrogel coupled with this type of antioxidants represents a promising alternative for potential application in post-infarction myocardial regeneration. Furthermore, this study proposes the best concentrations of proanthocyanidins that resulted in the hydrogels for future studies in cardiac tissue engineering.

Research progress of procyanidins in repairing cartilage injury after anterior cruciate ligament tear

Anterior cruciate ligament (ACL) tear is a common sports-related injury, and cartilage injury always emerges as a serious complication following ACL tear, significantly impacting the physical and psychological well-being of affected individuals. Over the years, efforts have been directed toward finding strategies to repair cartilage injury after ACL tear. In recent times, procyanidins, known for their anti-inflammatory and antioxidant properties, have emerged as potential key players in addressing this concern. This article focuses on summarizing the research progress of procyanidins in repairing cartilage injury after ACL tear. It covers the roles, mechanisms, and clinical significance of procyanidins in repairing cartilage injury following ACL tear and explores the future prospects of procyanidins in this domain. This review provides novel insights and hope for the repair of cartilage injury following ACL tear.

Effects of Covalent or Noncovalent Binding of Different Polyphenols to Acid-Soluble Collagen on Protein Structure, Functionality, and Digestibility

In this study, the structure, function, and digestibility of noncovalent complexes and covalent conjugates formed by acid-soluble collagen with polyphenols of different structures (quercetin, epicatechin, gallic acid, chlorogenic acid, procyanidin, and tannic acid) were investigated. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) showed that polyphenols were covalently bound to collagen by laccase catalytic oxidation. Biolayer interferometry revealed that the noncovalent binding strength of polyphenols to collagen from high to low was quercetin > gallic acid > chlorogenic acid > epicatechin, which was consistent with the trend of covalent polyphenol binding. Procyanidin and tannic acid had strong noncovalent binding, but their covalent binding ability was weak. Compared with the pure collagen, the complexes improved emulsification and antioxidant properties (more than 2.5 times), and the conjugates exhibited better thermal stability (99.4-106.8 °C) and antidigestion ability (reduced by more than 37%). The finding sheds new light on the use of collagen as a functional food ingredient in the food industry.

Polyphenols and polyphenols-based biopolymer materials: Regulating iron absorption and availability from spontaneous to controllable

Iron is an important trace element in the body, and it will seriously affect the body's normal operation if it is taken too much or too little. A large number of patients around the world are suffering from iron disorders. However, there are many problems using drugs to treat iron overload and causing prolonged and unbearable suffering for patients. Controlling iron absorption and utilization through diet is becoming the acceptable, safe and healthy method. At present, many literatures have reported that polyphenols can interact with iron ions and can be expected to chelate iron ions, depending on their types and structures. Besides, polyphenols often interact with other macromolecules in the diet, which may complicate this phenols-Fe behavior and give rise to the necessity of building phenolic based biopolymer materials. The biopolymer materials, constructed by self-assembly (non-covalent) or chemical modification (covalent), show excellent properties such as good permeability, targeting, biocompatibility, and high chelation ability. It is believed that this review can greatly facilitate the development of polyphenols-based biopolymer materials construction for regulating iron and improving the well-being of patients.

Unraveling the interaction of bisphenol A with collagen and its effect on conformational and thermal stability

Evidence suggests the association of bisphenol A (BPA) with increased collagen (COL) expression in the development of fibrosis. Ultraviolet and fluorescence spectra on collagen-BPA interaction showed that 100 ng/ml of BPA initiated loosening of protein backbone through unfolding with exposure of tyrosine residues resulting in an intermediate "Molten Globule" state, which later aggregated with 1 μg/ml of BPA indicated with an apparent red-shift. Conformational changes with CD and ATR-FTIR showed disappearance of negative band with broadening and shifting of peptide carbonyl groups. Light scattering findings with TEM images presented initial dissolution followed by unordered thick fibrillar bundles with 30 μg/ml BPA. The complex was pH sensitive, with calorimetric thermogram revealing increased thermal stability requiring 83°C to denature. Hydrogen bonds of 2.8 Å with hydrophobic interactions of BPA in all grooves of collagen molecule with same pattern and binding energy (-4.1 to -3.9 kcal/mol) confirmed the intensity of aggregate formation via in-silico docking.

Biocompatible Films of Collagen-Procyanidin for Wound Healing Applications

The study investigated the effect of polyphenols present in Cassia auriculata (CA) leaves in enhancing the stability of the collagen protein and the wound healing potential of collagen films. The crude ethanol extract of CA was analyzed for the presence of phytochemicals and purified by column chromatography using solvents with increasing polarity. The ethanol eluted active fractions (EEAF) that precipitated gelatin was characterized using HP-TLC, FTIR spectroscopy, ESI-FT-MS/MS, and ¹H NMR spectroscopy. The active compound was identified to be procyanidin B belonging to the proanthocyanidins group. The wound healing property of EEAF and collagen type I extracted from Clarias batrachus fish skin and the bovine tendon was assessed by in vitro scratch assay on L929 mice fibroblast cell lines. The EEAF-treated collagen coating enhanced in vitro wound closure in comparison with the uncoated dish. It was observed that EEAF treatment improved the physical strength of collagen films. The in vivo wound healing of the EEAF-treated collagen film was examined in male Wister rats and the wound site tissues were assessed. In vivo wound examination showed enhanced healing with EEAF incorporated collagen films. Comparatively, the EEAF-treated bovine tendon collagen films showed improved physical properties and better wound healing property than fish collagen films.