Oryza Oil & Fat Chemical Co., Ltd., Ichinomiya, Japan.
Pharmaceutical Research and Technology Institute, Kindai University, Higashi-osaka, Japan.
J Food Biochem. 2022 Oct;46(10):e14353. doi: 10.1111/jfbc.14353. Epub 2022 Aug 19.
Glucosylceramides (GlcCer), which are present in many edible plants, suppress melanin production in mouse melanocytes. Rice GlcCer consist of multiple molecules that comprise different types of sphingoid bases as well as diverse lengths and stereotypes of free fatty acids. Adjacent to the GlcCer fraction, there are free ceramides (Cer) as minor constituents. However, the anti-melanogenic activities of individual GlcCer and Cer remain unknown. Therefore, we herein isolated 13 GlcCer and elasticamide, a Cer [AP] from the gummy by-products of rice bran oil, and examined their anti-melanogenic activities. In theophylline-induced melanogenesis in B16 melanoma cells, GlcCer [d18:2(4E,8Z)/18:0], GlcCer [d18:2(4E,8Z)/20:0], and elasticamide significantly suppressed melanin production with IC values of 6.6, 5.2, and 3.9 μM, respectively. Elasticamide, but not GlcCer [d18:2 (4E,8Z)/20:0], suppressed melanogenesis in human 3D-cultured melanocytes and the expression of tyrosinase-related protein 1 in normal human melanocytes. Based on these results, we conducted a clinical trial on the effects of rice ceramide extract (Oryza ceramide®), containing 1.2 mg/day of GlcCer and 56 μg/day of elasticamide, on UV-B-induced skin pigmentation. The ingestion of Oryza ceramide for 8 weeks significantly suppressed the accumulation of melanin 7 days after UV irradiation (1288 and 1546 mJ/cm ·S). Rice-derived GlcCer and elasticamide, which exhibited anti-melanogenic activities, were suggested to contribute to the suppressive effects of Oryza ceramide on UV-induced skin pigmentation. Although the mechanisms underlying the anti-melanogenic activities of GlcCer remain unclear, elasticamide was identified as a promising Cer that exhibits anti-melanogenic activity. PRACTICAL APPLICATIONS: The anti-melanogenic activities of rice-derived GlcCer and elasticamide currently remain unclear. We herein demonstrated the inhibitory effects of individual GlcCer and elasticamide on melanogenesis in melanoma cells, melanocytes, and human skin.
葡萄糖神经酰胺（GlcCer）存在于许多食用植物中，可抑制小鼠黑素细胞中黑色素的生成。大米神经酰胺由多种分子组成，这些分子包含不同类型的神经酰胺碱基以及不同长度和类型的游离脂肪酸。在 GlcCer 馏分附近，还有少量的游离神经酰胺（Cer）作为次要成分。然而，单个 GlcCer 和 Cer 的抗黑色素生成活性仍然未知。因此，我们从米糠油的胶状副产物中分离出 13 种 GlcCer 和弹性酰胺[AP]，并检查了它们的抗黑色素生成活性。在茶碱诱导的 B16 黑色素瘤细胞的黑色素生成中，GlcCer[d18:2(4E,8Z)/18:0]、GlcCer[d18:2(4E,8Z)/20:0]和弹性酰胺的 IC 值分别为 6.6、5.2 和 3.9μM，可显著抑制黑色素生成。弹性酰胺，但不是 GlcCer[d18:2(4E,8Z)/20:0]，可抑制人 3D 培养黑素细胞中的黑色素生成和正常人黑素细胞中酪氨酸酶相关蛋白 1 的表达。基于这些结果，我们在紫外线 B 诱导的皮肤色素沉着患者中进行了含有 1.2mg/天 GlcCer 和 56μg/天弹性酰胺的大米神经酰胺提取物（Oryza ceramide®）的临床研究。Oryza ceramide 摄入 8 周可显著抑制紫外线照射后 7 天黑色素的积累（1288 和 1546mJ/cm·S）。具有抗黑色素生成活性的大米衍生 GlcCer 和弹性酰胺被认为有助于 Oryza ceramide 对紫外线诱导的皮肤色素沉着的抑制作用。尽管 GlcCer 的抗黑色素生成活性的机制尚不清楚，但弹性酰胺被确定为具有抗黑色素生成活性的有前途的 Cer。实际应用：大米衍生的 GlcCer 和弹性酰胺的抗黑色素生成活性目前尚不清楚。我们在此证明了单个 GlcCer 和弹性酰胺对黑色素瘤细胞、黑素细胞和人皮肤中黑色素生成的抑制作用。
