Water-Loss Prevention and Water-Holding Capacity of Jojoba Oils

Abstract

The seeds of jojoba (Simmondsia chinensis (Link) Schneider) contain approximately 50% of a unique oil known as jojoba oil. It is primarily composed of liquid wax monoesters, whose structure is similar to that of the wax component of human sebum and is widely employed as a cosmetic ingredient. Two types of jojoba oil are used in cosmetics: unrefined jojoba oil called “golden” jojoba oil and refined jojoba oil. Human sebum protects the epidermis by forming an emulsion with water, preventing water loss. In this study, the water-loss prevention and water-holding capacities of golden jojoba oil were measured and compared with those of refined jojoba oil and other oils. Golden jojoba oil exhibited the highest water-loss prevention and water-holding properties among the oils examined. These results suggest that golden jojoba oil is a useful cosmetic ingredient. Conversely, refined jojoba oil exhibited high water-loss prevention, albeit with the lowest water-holding capacity. These findings suggest that the minor components lost during the refining process are responsible for the high water-holding capacity of golden jojoba oil. When the methanol extract of golden jojoba oil was added to refined jojoba oil to examine water-loss prevention and water-holding capacity, no significant difference emerged between the two. Although the water-holding capacity of the refined jojoba oil increased, it remained lower than that of golden jojoba oil. These results suggest that, in addition to the minor substances in the methanol extract, other substances may contribute to the exceptional water-holding capacity of golden jojoba oil.