Skin-protective properties of peptide extracts produced from white sorghum grain kafirins

In recent years, the cosmetic industry has developed products that provide beneficial functions on the skin, with an increase in the production of cosmeceuticals which has generated great scientific and industrial interest in the search for alternative bioactive ingredients. The objective of this research was to determine the protective effects (antioxidant, anti-inflammatory, and anti-aging) of peptide extracts of the grain of white sorghum [Sorghum bicolor (L.) Moench] against the damage induced by exposure to ultraviolet B irradiation (UVB) in organotypic cultures of human skin. The kafirins (alpha, beta, and gamma-kafirin) fraction extracted from the sorghum grain was hydrolyzed with alcalase to produce crude hydrolysates. Then, by ultrafiltration, two peptide extracts with molecular weight 1-3 kDa (PE-3) and < 1 kDa (PE-1) were prepared. Bioassays were performed on organotypic skin cultures (exposed and not exposed to UVB). The results revealed that the treatments with both extracts (PE-3 and PE-1) significantly reduce the damage caused by UVB, by attenuating the depletion of the activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx), as well as by maintaining or increasing the activity of catalase (CAT). Also, PE-3 and PE-1 decreased the levels of pro-inflammatory cytokines such as interleukin 1-beta (1L-beta), interferon-gamma (IFN-gamma), and tumor necrosis factor-alpha (TNF-alpha). Furthermore, PE-3 and PE-1 inhibited collagenase, elastase, and tyrosinase activities. In general, PE-1 exhibited a greater protective effect than PE-3 and like that obtained with glutathione. Therefore, the enzymatic production of PE-3 and PE-1 with protective functions of the skin could be a promising strategy to generate potential ingredients that can be incorporated in new cosmeceutical formulations.

Automated summary

The peptide extracts from white sorghum grain demonstrated significant protective effects against UVB-induced skin damage, by reducing oxidative stress, inflammation, and aging. These extracts have the potential to be incorporated into new cosmeceutical formulations for skin protection.