Inhibition of Hyperpigmentation by Padina australis Hauck on B16F10 Melanoma Cells In Vitro and Emulgel Formulation

Several types of brown seaweed (Phaeophyceae) Hauck have been studied as active ingredients in skin-brightening cosmetics. However, Padina australis has not been specifically investigated as a skin-whitening agent. This study aims to examine the anti-melanogenic effects of Padina australis Hauck through ethyl acetate fractionation, purification using Preparative Thin Layer Chromatography (PTLC), and purity analysis with High-Performance Liquid Chromatography (HPLC) using fucoxanthin as a reference. The results showed that the isolate had the same spot pattern as fucoxanthin and a purity level of 96.8%, confirming its identity as fucoxanthin. Melanin content and depigmentation assays on B16F10 murine melanoma cells revealed that the ethyl acetate fraction (EAF) exhibited depigmentation activity of 55.47% without α-MSH (alpha-Melanocyte-Stimulating Hormone)  and 38.08% with α-MSH, with no significant difference compared to kojic acid (72,09% without and 66.813% with, α-MSH, p>0.05). An emulgel formulation containing EAF as an active ingredient showed a Sun Protection Factor (SPF) value of 13.289, categorized as providing maximum protection. Stability testing using a 12-cycle cycling test (4ºC and 40ºC) and additional evaluation on day 30 demonstrated that spreadability, adhesiveness, and viscosity remained stable. This study suggests that Padina australis has potential as an active skin-brightening agent, with an emulgel formulation offering effective SPF protection and excellent physical stability.