Luffa operculata seed proteins: Identification by LC-ESI-MS/MS and biotechnological potential against Candida albicans and C. krusei.

L: operculata is a plant commonly found in the North and Northeast of Brazil. Although the regional population knows its medicinal potential, there are few scientific studies about its antimicrobial potential. Thus, this study aimed to characterize the proteins from L. operculata seeds extracted using different solutions and evaluate their antimicrobial potentials. The protein extracts obtained with NaCl and sodium acetate buffer presented the best inhibitory activities against Candida albicans and C. krusei. The study of the mechanism of action revealed proteins from L. operculata seeds induced pore formation on the membrane and ROS overaccumulation. Scanning Electron Microscopy images also showed severe morphological changes in Candida albicans and C. krusei. Proteins from L.operculata seeds did not show antibacterial activity. The enzymatic assays revealed the presence of proteolytic enzymes, serine and cysteine protease inhibitors, and chitinases in both protein extracts. Proteomic analysis by LC-ESI-MS/MS identified 57 proteins related to many biological processes, such as defense to (a)biotic stress, energetic metabolism, protein folding, and nucleotide metabolism. In conclusion, the L. operculata seed proteins have biotechnological potential against the human pathogenic yeasts Candida albicans and C. krusei.