Preparation of nano/submicrometer yam and its benefits on collagen secretion from skin fibroblast cells.

Nano/submicrometer-scaled yam particles have been prepared by using media-milling. The particle size of media-milled yam was confirmed by the laser light scattering method and scanning electron microscopy. Influences of media-milled yam on skin fibroblast cells (WS1) were evaluated. The size reduction did not significantly alter the proximate composition, and the presence of nanoparticles was not toxic to WS1 cells. The contents of bioactive compounds (diosgenin, stigmasterol, and β-sitosterol) were significantly increased by media-milling, which enhanced the secretion of hTGF-β and inhibited the formation of MMP-1. Thus, the collagen secretion from WS1 was significantly increased by size reduction. Diosgenin was employed as a positive control. Nevertheless, media-milled yam exhibited greater effects on WS1 cells than diosgenin. It appeared that both diosgenin and size reduction were helpful for enhancing the secretion of collagen by WS1 cells. In addition, the irritancy of yam was eliminated by media-mil...