No abstract

Bui et al.: Antimicrobial, antioxidant and cytotoxic activities of Dialium cochinchinensisThis study was undertaken to evaluate the phytoconstituents present in the seed extract of Dialium cochinchinensis for antioxidant, antimicrobial and cytotoxic properties. Results showed the presence of polyphenols, flavonoids, alkaloids, saponins, coumarins and a polyuronid compound in the Dialium cochinchinensis seed extract. The total polyphenol and flavonoid contents of the dry extract were 133.5±2.87 mg GAE/g and 227.0±23.20 mg rutin equivalent/g, respectively. Dialium cochinchinensis seed extract exhibited antioxidant property in 2,2-diphenyl-1-picrylhydrazyl, 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid and potassium ferricyanide reducing antioxidant power methods. Moreover, Dialium cochinchinensis seed extract exerted inhibitory effect on Gram-positive bacteria. Finally, Dialium cochinchinensis seed extract was found to be toxic to Vero cell lines and the pathogens with selectivity index ranging from 0.01 to 0.04. In conclusion, Dialium cochinchinensis seed extract could be considered as a new source of natural antioxidant and antimicrobial agents for research and application.

In this study, the adhesive collagen-based hydrogels with antibacterial ability were prepared via arginine and dopamine modification, and the corresponding characterizations were also performed. A significant increase of N atom content from guanidine group was found via X-ray photoelectron spectroscopy (XPS), suggesting the guanidine groups were successfully introduced into the systems. The XRD and FTIR patterns indicated that arginine and dopamine did not interrupt the intact triple-helix conformation of collagen. Both the thermal stability and dynamic modulus of collagen hydrogels first increased and then decreased with the rising introduction of arginine. The increasing attachment of arginine retarded the further aggregations of collagen molecules due to the enhanced electrostatic repulsion, which was also confirmed by the microstructure observed by SEM. The antimicrobial activity of hydrogels modulus intensified significantly with the initial introduction of arginine (0.07 $ 0.28 mM) (p < 0.05) via the measurements of inhibition zone diameter and OD 260 value. However, the further addition of arginine did not result in the significant changes in the antibacterial performance. The biocompatibility of collagen hydrogels was not compromised, while the cell adhesiveness was improved. This work may provide a new strategy for the design of collagenbased antibacterial hydrogels for the wound dressing applications.

No abstract