Dietary Ceramide Prepared from Soy Sauce Lees Improves Skin Barrier Function in Hairless Mice

Dietary sphingolipids such as glucosylceramide and sphingomyelin are known to improve the skin barrier function of damaged skin. In this study, we focused on free-ceramide prepared from soy sauce lees, which is a byproduct of soy sauce production. The effects of dietary soy sauce lees ceramide on the skin of normal mice were evaluated and compared with those of dietary maize glucosylceramide. We found that transepidermal water loss value was significantly suppressed by dietary supplementation with soy sauce lees ceramide as effectively as or more effectively than maize glucosylceramide. Although the content of total and each subclass of ceramide in the epidermis was not significantly altered by dietary sphingolipids, that of 12 types of ceramide molecules, which were not present in dietary sources, was significantly increased upon ingestion of maize glucosylceramide and showed a tendency to increase with soy sauce lees ceramide intake. In addition, the mRNA expression of ceramide synthase 4 and involucrin in the skin was downregulated by sphingolipids. This study, for the first time, demonstrated that dietary soy sauce lees ceramide enhances skin barrier function in normal hairless mice, although further studies are needed to clarify the molecular mechanism

Lipid-soluble polyphenols from sweet potato exert antitumor activity and enhance chemosensitivity in breast cancer

Polyphenols are abundant in vegetables and fruit. They have been shown to have various antitumor, antioxidant, and anti-inflammatory effects. Here, we extracted the lipid-soluble fraction of polyphenols from fermented sweet potato ( Ipomoea batatas) . These lipid-soluble polyphenols (PPL) mainly contained caffeic acid derivatives with strong antioxidant ability, which we hypothesized to affect diseases for which oxidative stress is a factor, such as cancer. We therefore investigated the antitumor and chemosensitizing effects of PPL on E0771 murine breast cancer cells. The PPL accumulated in the cells’ cytoplasm due to its high lipophilicity, and reduced reactive oxygen species through its strong antioxidant activity. The PPL also arrested the cell cycle at G 0 /G 1 by suppressing Akt activity, and enhanced the cytotoxicity of anticancer agents. In this model, PPL inhibited tumor growth and enhanced the efficacy of chemotherapy drugs. These results suggest the potential of PPL as a functional food to support cancer therapy