Diverse effects of single molecules of rice-derived functional lipids, glucosylceramides, ceramides, and β-sitosterol glucoside, on epidermal and lung functions
2023 年 10 巻 3 号 p. 94-109
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2023 年 10 巻 3 号 p. 94-109
Glucosylceramides (GlcCer), ceramides (Cer), and β-sitosterol glucoside (BSG) are produced in the refining process of rice bran oil. GlcCer are used for functional foods that claim to promote skin barrier functions and moisturization. However, the efficacies of single molecules of GlcCer, Cer, and BSG remain unclear. Therefore, we herein examined the effects of rice-derived GlcCer, Cer, and BSG on skin. The anti-inflammatory effects of BSG in a mouse pneumonia model were also investigated. Skin barrier effects were assessed based on transepidermal water loss (TEWL) in a reconstructed human epidermal keratinization model. The results obtained showed that GlcCer[d18:2(4E,8Z)] with C18 to C26 fatty acids, Cer[t18:0/24:0], and BSG decreased TEWL. The suppressive effect of GlcCer was dependent on the length of fatty acids, while Cer[t18:0/24:0] and GlcCer[d18:2(4E,8Z)/26:0] exerted similar strong effects. GlcCer[d18:2(4E,8Z)] with C18 and C20 fatty acids and Cer[t18:0/24:0] suppressed melanogenesis in B16 melanoma cells. Furthermore, BSG prolonged the survival of influenza-infected mice and increased blood O2 saturation in lipopolysaccharide-induced pneumonia mice. In conclusion, GlcCer promoted barrier function in a fatty acid length-dependent manner and up-regulated the expression of filaggrin. Cer[t18:0/24:0] strongly promoted barrier functions by increasing the production of Cer[NS/NDS]. GlcCer[d18:2(4E,8Z)] with C18 and C20 fatty acids and Cer[t18:0/24:0] suppressed melanogenesis. These results suggest that specific GlcCer and Cer promote epidermal barrier functions and exhibit anti-melanogenic activity, leading to clinical efficacy. BSG also contributed to epidermal and lung barrier functions. Therefore, these 3 components in rice oil by-products are beneficial for skin and lung health.
