Cath-DM-NT, a peptide derived from the skin of Duttaphrynus melanostictus, shows dual lectin-like and antioxidant activity.

Chansu, a mixture extracted from Duttaphrynus melanostictus or Bufo gargarizans Cantor, is a traditional Chinese medicine with a broad range of medical applications. However, the peptides/proteins in it have not received adequate attention. Herein, a Cathelicidin-DM-derived peptide named Cath-DM-NT was identified from the skin of D. melanostictus. Previous studies have shown that Cathelicidin-DM has significant antibacterial activity, while Cath-DM-NT has no antibacterial activity. In this study, Cath-DM-NT is found to have lectin-like activity which can agglutinate erythrocytes and bacteria, and bind to lipopolysaccharide (LPS). In addition, Cath-DM-NT has antioxidant activity, which can scavenge 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), 1,1-diphenyl-2-picrylhydrazyl (DPPH), and nitric oxide (NO) radicals and reduce Fe3+. Consistently, Cath-DM-NT can protect PC12 cells from H2O2-induced oxidative damage and carrageenan-induced paw edema, reduce malondialdehyde (MDA) and reactive oxygen species (ROS) accumulation, and restore superoxide dismutase (SOD) and glutathione (GSH) levels. Our study suggests that Cath-DM-NT can serve as a lead compound for the development of drugs with dual lectin and antioxidant effects.

Esc-1GN shows therapeutic potentials for acne vulgaris and inflammatory pain.

The inflammatory response plays important roles in acne vulgaris and pain pathogenesis. In previous study, Esc-1GN with anti-inflammatory, antimicrobial, and lipopolysacchride (LPS) binding activity was identified from the skin of the frog Hylarana guentheri. Here, we report its therapeutic potentials for acne vulgaris and inflammatory pain. Esc-1GN destroyed the cell membrane of Propionibacteria acnes in the membrane permeability assays. In addition, bacterial agglutination test suggested that Esc-1GN triggered the agglutination of P. acnes, which was affected by LPS and Ca2+ . Meanwhile, in vivo anti-P. acnes and anti-inflammatory effects of Esc-1GN were confirmed by reducing the counts of P. acnes in mice ear, relieving P. acnes-induced mice ear swelling, decreasing mRNA expression and the production of pro-inflammatory cytokines, and attenuating the infiltration of inflammatory cells. Moreover, Esc-1GN also displayed antinociceptive effect in mice induced by acetic acid and formalin. Therefore, Esc-1GN is a promising candidate drug for treatment of acne vulgaris and inflammatory pain.