Stability, release, and tyrosinase inhibition behaviors of kojic acid encapsulated in the interlayer space of layered yttrium hydroxide

• Published in: Applied clay science Vol. 260; p. 107547
• Main Authors: Kang, Myeongjin, Choi, Yoonjae, Byeon, Song-Ho
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-11-2024
• Subjects: Host-guest reaction; Kojic acid; Layered yttrium hydroxide; Tyrosinase inhibition; Host-guest reaction; Tyrosinase inhibition; Layered yttrium hydroxide; Kojic acid
• ISSN: 0169-1317
• DOI: 10.1016/j.clay.2024.107547

Kojic acid (KA) is widely utilized in cosmetic formulations for skin brightening and as a food preservative to prevent oxidative browning in fruits and vegetables. However, its effectiveness is compromised by susceptibility to pH and temperature fluctuations, as well as oxidation after exposure to UV light. These limitations highlight the need for improvements to facilitate sustainable applications. In this study, KA was encapsulated within the interlayer space of layered yttrium hydroxide (LYH) through a two-step host-guest reaction involving dodecylsulfate and basic ethoxide anions. Examination of the X-ray diffraction (XRD) pattern of the resulting product (KA-LYH) revealed an expanded interlayer space from approximately 8.4 to 16.7 Å, conducive to a partially interdigitated bilayer arrangement of KA anions within the LYH interlayer. KA-LYH demonstrated significantly improved stability against light, heat, and oxygen compared to free KA, indicating effective confinement and protection of KA from photoreaction and oxidation in the interlayer space of LYH host. Minimal release of KA was observed in saline solution and simulated seawater, while sustained release occurred in a phosphate buffer solution even after 24 h. Notably, the KA released from the LYH interlayer space retained potent tyrosinase inhibition activity, showcasing the sustainable efficacy of KA-LYH under physiological conditions.
•Kojic acid (KA) utilized in cosmetic formulations and as a food preservative requires improvements.•Layered yttrium hydroxide (LYH) has emerged as a promising class of anionic clays.•Two-step host-guest reaction route was developed to intercalate KA into the interlayer space of LYH.•The resulting KA-LYH showed highly enhanced stability while maintaining the tyrosinase inhibition effect.•Sustained release of KA from KA-LYH occurred selectively in PBS of physiological pH.