Development and efficacy of arbutin-loaded agarose hydrogel for antioxidant and depigmentation applications

Skin whitening and depigmentation are key strategies in skincare, representing a major global market. However, prolonged use of high concentrations of chemicals in skincare products can lead to skin disorders and premature aging. Biopolymer-based hydrogels offer a promising alternative by enabling sustained transdermal delivery of bioactive molecules while minimizing adverse effects. This study aimed to develop a novel bioactive hydrogel using thermosensitive, low-temperature-melting agarose (AGE) and the non-toxic tyrosinase inhibitor arbutin (ABN). Fourier transform infrared spectroscopy (FTIR) analysis confirmed the successful incorporation of ABN into the AGE hydrogel, while X-ray diffraction (XRD) analysis revealed the formation of new amorphous peaks, indicating composite hydrogel formation. Field emission scanning electron microscope (FE-SEM) imaging showed that freeze-dried AGE-ABN exhibited a smaller, more longitudinal porous structure compared to AGE alone. ABN release was dependent on its initial concentration, with higher release rates correlating with increased antioxidant activity. The 10-minute extract of freeze-dried AGE-ABN (0.1 %) hydrogel demonstrated DPPH (39.16 ± 0.72 %), FRAP (78.37 ± 2.24 %), and ABTS (92.40 ± 0.02 %) radical scavenging activities. Additionally, AGE-ABN (0.1 %) exhibited significant tyrosinase inhibition (27.90 ± 0.02 %), highlighting its potential for depigmentation. Importantly, the hydrogel promoted a human keratinocyte (HaCaT) cell growth without inducing cytotoxicity.