Effects of aqueous extract from Apostichopus japonicus on melanogenesis in B16F10 cells and zebrafish

Apostichopus japonicus is preserved in dried form after processing and used as food and traditional medicine. During the sea cucumber drying process, the boiled liquid is discarded as waste. In this study, the freeze-dried powder obtained from the boiled aqueous extracts from sea cucumbers cultured in Japan and Taiwan (SCAE-Tw and SCAE-Jp) were used to observe the anti-melanogenesis effects of the extracts on B16F10 cells and zebrafish embryos. A foam test, Fourier transform infrared (FTIR), and ultraviolet (UV) spectra analysis revealed that SCAEs had amphiphilic features similar to saponin. According to the saponin standard, we calculated that SCAE-Tw and SCAE-Jp contained 3.45 and 6.48 mg, respectively, of the saponin component per 100 mg after the lyophilization treatment. The survival rate experiments indicated that the lethal concentration in B16F10 cells is 54 and 201 μg/mL, respectively. The anti-melanogenic activity of the SCAEs was confirmed by assessing the inhibition of melanin content and intracellular tyrosinase activity in B16F10 cells and zebrafish embryos. qPCR analysis demonstrated that SCAEs suppressed the expression of Mitf, Tyr, and Trp-1 in a concentration-dependent manner. This research may provide new insights into the reuse of food processing wastewater and the development of novel anti-melanin treatments and applications in aquaculture, cosmetics, and medicine.