Antioxidant potency of highly purified polyepicatechin fractions

In Vitro Culture of Human Dermal Fibroblasts on Novel Electrospun Polylactic Acid Fiber Scaffolds Loaded with Encapsulated Polyepicatechin Physical Gels

Polyepicatechin (PEC) in a hydrogel has previously shown promise in enhancing physiological properties and scaffold preparation. However, it remains unclear whether PEC-based fibers can be applied in skin tissue engineering (STE). This study aimed to synthesize and characterize electrospun PEC physical gels and polylactic acid (PLA) scaffolds (PLAloadedPECsub) for potential use as constructs with human dermal fibroblasts (HDFs). PEC was produced through enzymatic polymerization, as confirmed by Fourier transform infrared (FTIR) spectroscopy. Scanning electron microscopy (SEM) demonstrated the feasibility of producing PLAloadedPECsub by electrospinning. The metabolic activity and viability of HDFs cocultured with the scaffolds indicate that PLAloadedPECsub is promising for the use of STE.

Antioxidant Activity of Synthetic Polymers of Phenolic Compounds

In recent years, developing potent antioxidants has been a very active area of research. In this context, phenolic compounds have been evaluated for their antioxidant activity. However, the use of phenolic compounds has also been limited by poor antioxidant activity in several in vivo studies. Polymeric phenols have received much attention owing to their potent antioxidant properties and increased stability in aqueous systems. To be truly effective in biological applications, it is important that these polymers be synthesized using benign methods. In this context, enzyme catalyzed synthesis of polymeric phenols has been explored as an environmentally friendly and safer approach. This review summarizes work in enzymatic syntheses of polymers of phenols. Several assays have been developed to determine the antioxidant potency of these polymeric phenols. These assays are discussed in detail along with structure-property relationships. A deeper understanding of factors affecting antioxidant activity would provide an opportunity for the design of versatile, high performing polymers with enhanced antioxidant activity.

Antioxidant Capacity and Cytotoxic Effects of Catechins and Resveratrol Oligomers Produced by Enzymatic Oxidation against T24 Human Urinary Bladder Cancer Cells

In this work the polymerization of catechin, epicatechin, and resveratrol was carried out through a peroxidase oxidation process in order to improve the biological activity of these phenolic compounds. The antioxidant activity of the oligomers was evaluated by their ability to scavenge reactive oxygen species (ROS) and their capacity to chelate metal ions Fe2+ and Cu2+. The antitumor effect of the oligomers was determined by their ability to induce toxicity in the T24 human bladder cancer cell line. By enzymatic peroxidase oxidation, it was possible to produce oligomers of catechin, epicatechin, and resveratrol with antioxidant capacity significantly higher than their preceding monomers. The ROS scavenging capacity of the oligomers was 20 times higher than that of the monomers, while the ability of the oligomers to chelate metal ions increased up to about 1000 times. Our data show the antitumor effect of the oligomers of catechin, epicatechin, and resveratrol in the T24 cell line, which was similar to that observed with cisplatin. Oligomers of catechin, epicatechin, and resveratrol have great potential to be used as therapeutic agents for the treatment of oxidative stress-related diseases and bladder cancer.

Comprehensive investigation of the enzymatic oligomerization of esculin by laccase in ethanol : water mixtures

The oligomerization of esculin by laccase in aqueous medium resulted in a precipitate fraction with excellent antioxidant properties.

A computational investigation on the structure, global parameters and antioxidant capacity of a polyphenol, Gallic acid

A computational DFT-B3LYP structural analysis of a poly phenol, Gallic acid (GA) has been performed by using 6-311++ G (df, p) basis set. The GA is a relatively stable molecule with considerable radical scavenging capacity. It is a well known antioxidant. The NBO analysis shows that the aromatic system is delocalized. The results reveal that the most stable radical is formed at O₃-atom upon scavenging the free radicals. Global descriptive parameters show that GA acts as an acceptor center in charge transfer complex formation which is supported by ESP and contour diagrams and also by Q^max value. The GA is a good antioxidant and it can be better understood by HAT and TMC mechanisms as it has low BDE, ΔH_acidity and ΔG_acidity values. The ΔBDE and ΔAIP values also confirm that the antioxidant capacity of GA can be explained through HAT rather than the SET-PT mechanism.

α-Glucosidase inhibiton and antiglycation activity of laccase-catalyzed catechin polymers

Catechin polymers were produced by laccase (12 U/mL) in a mixture of sodium acetate buffer (1% (+)-catechin, 100 mM, pH 5) and methanol (buffer:methanol = 95:5, v/v). The freeze-dried catechin polymers were recovered from the precipitate after dialysis followed by centrifugation. Catechin polymers extracted with 20% ethanol had potent inhibitory activity against α-glucosidase with an IC50 value of 4 μg/mL, and they were present as a mixture of dimers, trimers, and tetramers. The antihyperglycemic effect of the catechin polymers was confirmed by an oral maltose tolerance test. The catechin polymers also had significantly improved antiglycation and superoxide dismutase-like activities compared to those of (+)-catechin. Since formation of advanced glycation end products and oxidative stress are accelerated in hyperglycemic conditions, we suggest that enzymatic production of catechin polymers could have a potential protective effect in type 2 diabetes, diabetic complications, and other free radical related diseases.