Evaluation of the genotoxic, DNA-protective and antioxidant profile of synthetic alkyl gallates and gallotannins using in vitro assays

An Integrated Approach to the Anti-Inflammatory, Antioxidant, and Genotoxic Potential of Portuguese Traditional Preparations from the Bark of Anacardium occidentale L

Anacardium occidentale L. stem bark Traditional Herbal Preparations (AoBTHPs) are widely used in traditional medicine to treat inflammatory conditions, such as diabetes. The present study aims to evaluate the anti-inflammatory, antioxidant, and genotoxic potential of red and white Portuguese AoBTHPs. Using a carrageenan-induced rat paw edema model, a significant anti-edema effect was observed for all tested doses of white AoBTHP (40.2, 71.5, and 127.0 mg/kg) and the two highest doses of red AoB THP (71.5 and 127.0 mg/kg). The anti-edema effect of red AoBTHP's highest dose was much more effective than indomethacin 10 mg/kg, Trolox 30 mg/kg, and Tempol 30 mg/kg. In DPPH, FRAP, and TAC using the phosphomolybdenum method, both types of AoBTHPs showed similar antioxidant activity and no genotoxicity up to 5000 µg/plate in the Ames test. The LC-UV/DAD-ESI/MS fingerprint allowed the identification of gallic and protocatechuic acids as the two main marker compounds and the presence of catechin, epicatechin, epigallocatechin gallate, and ellagic acid in both AoBTHPs. The obtained results support the validation of red and white AoB and their THPs as anti-inflammatory agents and contribute to the possible development of promising new therapeutic options to treat inflammatory conditions.

Recognition of Gallotannins and the Physiological Activities: From Chemical View

Gallotannins, characterized with the glycosidic core and galloyl unit, are seemed as vital components of hydrolyzable tannins. Benefit from the more and more discoveries of their bioactivities and edibility, application of gallotannins in food industry, pharmacy industry, and other fields is increasing. Inheriting previous study achievements, chemical structure of gallotannins was illustrated and degradation as well as synthetic routes to gallotannins were summarized. On this basis, distribution in the nature also including the distinction of gallotannins was discussed. More than that, activities involving in antioxidant, anti-inflammatory, enzyme inhibitions, protein binding, and so on, as well as applications in the field of food industry, biopharmaceutical science, agricultural production, etc., were combed. Finally, improvement of bioavailability, chemical modification of the structure, and accurate determination of new gallotannins were pointed out to be the orientation in the future.

Laccase-Catalyzed Grafting of Lauryl Gallate on Chitosan To Improve Its Antioxidant and Hydrophobic Properties

Biografting is a promising and ecofriendly approach to meet various application requirements of products. Herein, a popular green enzyme, laccase, was adopted to graft a hydrophobic phenolic compound (lauryl gallate, LG) onto chitosan (CTS). The resultant chitosan derivate (Lac/LG-CTS) was systematically analyzed by Fourier transform infrared (FTIR), grafting efficiency, scanning probe microscopy (SPM), and X-ray diffraction (XRD). This grafting technique produced a multifunctional chitosan copolymer with remarkably enhanced antioxidant property, hydrophobicity, and moisture barrier property. Furthermore, the swelling capacity and acid solubility of the copolymer film decreased significantly, although the tensile strength and elongation were slightly weakened as compared to those of native chitosan. These results suggest that the Lac/LG-CTS holds great potential as a food-packaging material, preservative agent, or edible coating material.

New Unnatural Gallotannins: A Way toward Green Antioxidants, Antimicrobials and Antibiofilm Agents

Nature has been a source of inspiration for the development of new pharmaceutically active agents. A series of new unnatural gallotannins (GTs), derived from d-lyxose, d-ribose, l-rhamnose, d-mannose, and d-fructose have been designed and synthesized in order to study the protective and antimicrobial effects of synthetic polyphenols that are structurally related to plant-derived products. The structures of the new compounds were confirmed by various spectroscopic methods. Apart from spectral analysis, the antioxidant activity was evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging and iron reducing power (FRAP) assays. Antibacterial activity of compounds was tested in vitro against Staphylococcus aureus ATCC 29213, Enterococcus faecalis ATCC 29212 (reference and control strains), three methicillin-resistant isolates of S. aureus, and three isolates of vancomycin-resistant E. faecalis. For screening of antimycobacterial effect, a virulent isolate of Mycobacterium tuberculosis and two non-tuberculous mycobacteria were used. Furthermore, antibiofilm activity of structurally different GTs against S. aureus, and their ability to inhibit sortase A, were inspected. Experimental data revealed that the studied GTs are excellent antioxidants and radical-scavenging agents. The compounds exhibited only a moderate antibacterial effect against Gram-positive pathogens S. aureus and E. faecalis and were practically inactive against mycobacteria. However, they were efficient inhibitors and disruptors of S. aureus biofilms in sub-MIC concentrations, and interacted with the quorum-sensing system in Chromobacteriumviolaceum. Overall, these findings suggest that synthetic GTs could be considered as promising candidates for pharmacological, biomedical, consumer products, and for food industry applications.

Antioxidant, Cytotoxic, Genotoxic, and DNA-Protective Potential of 2,3-Substituted Quinazolinones: Structure-Activity Relationship Study

The evaluation of antioxidant compounds that counteract the mutagenic effects caused by the direct action of reactive oxygen species on DNA molecule is of considerable interest. Therefore, a series of 2,3-substituted quinazolinone derivatives (Q1-Q8) were investigated by different assays, and the relationship between their biological properties and chemical structure was examined. Genotoxicity and the potential DNA-protective effects of Q1-Q8 were evaluated by comet assay and DNA topology assay. Antioxidant activity was examined by DPPH-radical-scavenging, reducing-power, and total antioxidant status (TAS) assays. The cytotoxic effect of compounds was assessed in human renal epithelial cells (TH-1) and renal carcinoma cells (Caki-1) by MTT assay. Analysis of the structure-activity relationship disclosed significant differences in the activity depending on the substitution pattern. Derivatives Q5-Q8, bearing electron-donating moieties, were the most potent members of this series. Compounds were not genotoxic and considerably decreased the levels of DNA lesions induced by oxidants (H2O2, Fe2+ ions). Furthermore, compounds exhibited higher cytotoxicity in Caki-1 compared to that in TH-1 cells. Substantial antioxidant effect and DNA-protectivity along with the absence of genotoxicity suggested that the studied quinazolinones might represent potential model structures for the development of pharmacologically active agents.

Effects of Functionalized Fullerenes on ROS Homeostasis Determine Their Cytoprotective or Cytotoxic Properties

BACKGROUND

Functionalized fullerenes (FF) can be considered regulators of intracellular reactive oxygen species (ROS) homeostasis; their direct oxidative damage-as well as regulation of oxidant enzymes and signaling pathways-should be considered.

METHODS

Uptake of two water-soluble functionalized C₇₀ fullerenes with different types of aromatic addends (ethylphenylmalonate and thienylacetate) in human fetal lung fibroblasts, intracellular ROS visualization, superoxide scavenging potential, NOX4 expression, NRF2 expression, oxidative DNA damage, repair genes, cell proliferation and cell cycle were studied.

RESULTS & CONCLUSION

The intracellular effects of ethylphenylmalonate C₇₀ derivative (FF1) can be explained in terms of upregulated NOX4 activity. The intracellular effects of thienylacetate C₇₀ derivative (FF2) can be probably resulted from its superoxide scavenging potential and inhibition of lipid peroxidation. FF1 can be considered a NOX4 upregulator and potential cytotoxicant and FF2, as a superoxide scavenger and a potential cytoprotector.