Antimelanogenesis of quercetin-related compounds in B16 melanoma cells: the difference moieties of C-3 position and its effect on H2O2

Quercetin ( compound 2 ), isolated from the dried skin of Allium cepa , and 3-prenyl luteolin ( compound 6 ), derived from the wood of Artocarpus heterophyllus , are polyphenolic compounds with demonstrated potential in regulating melanogenesis. This study investigated their anti-melanogenic activity and reactive oxygen species (ROS) scavenging effects, particularly against hydrogen peroxide (H₂O₂), in B16 melanoma cells. Both compounds significantly suppressed melanin synthesis, indicating potential as natural depigmenting agents. Quercetin ( 2 ) exhibited a half-maximal inhibitory concentration (IC₅₀) of 8.0 µg/mL, while 3-prenyl luteolin ( 6 ) showed an IC₅₀ of 20.1 µg/mL. For comparison, compound 1 displayed the strongest activity with an IC₅₀ of 3.0 µg/mL, whereas compounds 3 – 5 demonstrated no appreciable inhibitory effects. Additionally, both compounds reduced intracellular H₂O₂ levels, supporting their antioxidative role in mitigating oxidative stress-induced melanogenesis. These findings highlight the potential application of quercetin and 3-prenyl luteolin as novel active ingredients in skin-whitening formulations through dual mechanisms of melanin synthesis inhibition and ROS reduction.