Oryza Ceramide®, a rice-derived extract consisting of glucosylceramides and β-sitosterol glucoside, improves facial skin dehydration in Japanese subjects

Background and objective: The ingestion of plant-derived glucosylceramides (GlcCer) has been reported to contribute to skin barrier function and hydration of the epidermis. b-sitosterol glucoside (BSG) colocalized with GlcCer in the rice hydrophobic fraction has been shown to increase ceramides in the stratum corneum in vitro. Although clinical studies demonstrated that GlcCer reduced transepidermal water loss (TEWL), the contribution of BSG to epidermal dehydration when applied with GlcCer remains unknown. Therefore, we herein conducted a clinical trial on the effects of a rice-derived mixed fraction of GlcCer and BSG (Oryza Ceramide®) on TEWL and other skin parameters. Methods: A randomized, double-blind, placebo-controlled study design was used. Oryza Ceramide® (type PCD, 40 mg daily) containing 1.2 mg of GlcCer and 40 mg of BSG was used as the active sample. We enrolled 44 healthy Japanese women with epidermal dehydration. All subjects were randomly allocated to an active group (n=22) or placebo group (n=22) using a computerized random number generator. Capsules containing the active sample or placebo were administered for 12 weeks between August and December 2020. Cheek TEWL after 12 weeks was assessed as the primary outcome, and TEWL on a different part of the skin and various skin parameters, including epidermal moisture, pigmentation, pores, and elasticity, were measured before and after 4, 8, and 12 weeks of the intervention. Blood, urine, and body parameters were also examined to evaluate safety.Results: Forty-four subjects completed the trial, and the per protocol set comprised 22 each in the active and placebo groups. Cheek TEWL significantly reduced after the Oryza Ceramide® intervention for 4 and 12 weeks. Among the secondary outcomes examined, lip moisture (12 weeks) and visible pore number (4 weeks) were improved by Oryza Ceramide®. Laboratory tests revealed no abnormalities to suggest any adverse effects of Oryza Ceramide®.Conclusions: Oryza Ceramide® (40 mg/day) consisting of GlcCer and BSG improved facial TEWL, lip moisture, and visible pores, and these effects may be attributed to increases in epidermal ceramides. The combination of rice GlcCer and BSG appears to be beneficial for improving facial skin conditions.Trial Registration: UMIN-CTR: UMIN000041295Foundation: The study was funded by Oryza Oil & Fat Chemical Co., Ltd. and Aichi Prefectural Subsidies for Research and Development of Creative Products in 2020.Keywords: rice; glucosylceramide; β-sitosterol glucoside; trans epidermal water loss; pore