The Antioxidant and Skin-Brightening Effects of a Novel Caffeic Acid Derivative, Caffeic Acid-3,4-Dihydroxyphenylpropanolester

Caffeic acid (CA) is a naturally occurring polyphenol antioxidant found in coffee, tea, fruits, and vegetables, known for its strong antioxidant, anti-inflammatory, and anti-aging properties. However, its cosmetic application is limited because of poor dermal absorption due to its high polarity. This study aimed to evaluate the antioxidant and skin-brightening effects of a novel lipophilic CA derivative, CAD (caffeic acid-3,4-dihydroxyphenylpropanolester). CAD was synthesized by conjugating CA with 3,4-DHPEA, a lipophilic antioxidant derived from olive oil. In both DPPH and ABTS assays, CAD exhibited more potent antioxidant activity than CA. In B16F10 melanoma cells, CAD significantly inhibited melanin production without cytotoxicity at concentrations lower than those required for CA. Cellular assays using DCF-DA staining demonstrated that CAD effectively reduced intracellular ROS levels. Mechanistic studies revealed that CAD inhibited tyrosinase activity and downregulated the expression of TYR, TRP-1, and TRP-2. Additionally, CAD suppressed MITF phosphorylation, along with reduced phosphorylation of ERK and JNK, elucidating its anti-melanogenic mechanism. Importantly, CAD showed dose-dependent skin-brightening effects in the 3D human skin model Melanoderm™, as evidenced by increased lightness and histological evaluation. In conclusion, CAD demonstrates strong potential as a safe and effective antioxidant and skin-brightening agent for cosmetic applications.