Objective: The oxyresveratrol, polyphenol from Morus alba (Mulberry) roots has been known to have potential skin whitening activities. The application of urea-glycerin-based Natural Deep Eutectic Solvent-Ultrasonic Assisted Extraction (NADES-UAE) method was successful on extraction of polyphenols from plant material. The purpose of this research was to get optimum extraction conditions to enhance oxyresveratrol content and get the best lotion formula based on physical properties evaluation. Methods: The roots were extracted with urea-glycerin-based NADES-UAE method. The NADES-UAE method was employed to determine the optimal extraction condition for two parameters: the molar ratio of urea: glycerin and ultrasonic irradiation time. Oxyresveratrol concentration of the extracts was analyzed with HPLC. Morus alba roots extract was formulated into three formulas of lotion preparation and evaluated based on their physical properties. Results: The optimized conditions for the highest oxyresveratrol concentration from Morus alba roots extract were the molar ratio of urea-glycerin (1:3) and ultrasonic irradiation time as 15 mins. It showed that urea-glycerin UAE method produced Morus alba roots extract with higher oxyresveratrol content than conventional method. Based on physical evaluation from three lotion formulas, formula A was chosen as best formula. Conclusion: This urea-glycerin-based NADES-UAE method was suitable as a green alternative method for the extraction of oxyresveratrol from Morus alba roots because cheaper, faster and easier than conventional extraction method. The lotion preparation which has good physical properties can be applied as a skin whitening cosmetic.
Key words: Natural deep eutectic solvent, Ultrasonic assisted extraction, Urea, Glycerin, Oxyresveratrol, Morus alba, Roots extract, Skin whitening.