Seed Watermelon (Citrullus mucosospermus (Fursa))-Derived Coniferyl Alcohol as a Functional Ingredient in Remedies for Dry Skin: Evidence of Facilitated Lipogenesis in Human Sebocytes

Sebum secreted by sebaceous glands mixes with sweat to form a protective film that aids in maintaining skin health. Reduced sebum production compromises such barrier functions, potentially leading to severe itchiness and inflammation. Therefore, incorporating moisturizers with ingredients promoting sebum secretion is desirable. Wild watermelon possesses moisturizing and antioxidant properties, and its extracts are utilized in skin cosmetics and supplements. This study investigates whether seed watermelon (Citrullus mucosospermus (Fursa))-a species closely related to wild watermelon-influences sebum synthesis and can serve as a skin cosmetic raw ingredient. Several bioactive compounds-including coniferyl alcohol, coniferin, and p-coumaryl alcohol-were identified in the active third fraction of the fruit extract. Subsequently, SZ95 sebocytes stimulated with linoleic acid were stained using Oil Red O to detect lipogenesis facilitated by the identified bioactive compounds. Coniferyl alcohol promoted linoleic acid-stimulated lipogenesis by approximately 2.2-fold at a concentration of 300 µM. Lipidomic analyses confirmed an increase in total lipid content following coniferyl alcohol treatment, with notable increases in Cholesterol ester, cardiolipin, and simple lipid content. Overall, these findings suggest that seed watermelon contains compounds that do influence sebum synthesis. Consequently, skin cosmetics containing seed watermelon fruit extracts with linoleic acid may benefit individuals with dry skin.

SZ95 cells; coniferyl alcohol; linoleic acid; lipogenesis; seed watermelon.