## 3 Results and Discussion
### Effect of FNGB and FGB Ethanol Extracts on the Morphology of Zebrafish Embryos  
Antioxidants can reduce excessive reactive oxygen species (ROS) generation caused by ultraviolet and oxidative stress, which may lead to skin-related diseases. Therefore, ROS scavengers or inhibitors, in addition to other antioxidants, have melanogenesis reducing potential [9]. The results displayed that the ethanol extract of germinated black soy milk fermented with TWK10 had higher total phenolic and flavonoid content than the water extract. In addition, in the DPPH free radical scavenging capacity test, the ethanol extracts of FNGB and FGB had better antioxidant activity, with no significant differences in the capacity of scavenging DPPH free radicals from ASA, which was marketed for skin-lightening (\(p>0.05\)). Zebrafish embryos produce large amounts of melanin during normal growth and development. Therefore, a zebrafish animal model was used to evaluate the effects of FNGB and FGB ethanol extracts on melanogenesis in its embryos.  
The effects of the FNGB and FGB ethanol extracts on the morphology of zebrafish embryos are shown in Figures 3 and 4. No malformation of the zebrafish embryo was observed when the FNGB or FGB ethanol extract concentration was 10-100 \(\upmu\)g/mL. However, when treated with 250 \(\upmu\)g/mL of FNGB or FGB ethanol extract, curved tails, deformed backs, and enlarged yolk cysts were observed in zebrafish embryos. Based on the preliminary results above, FNGB or FGB ethanol extract concentration of lower than 100 \(\upmu\)g/mL would not lead to zebrafish malformations.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Samples**} & \multicolumn{3}{c}{**Inhibition (\% of Control)**} \\ \cline{2-4}  & \multicolumn{2}{c}{**Concentrations (mg/mL)**} & \multicolumn{1}{c}{**ASA**} \\ \cline{2-4}  & **10** & **5** & **2** & **(100 \(\upmu\)g/mL)** \\ \hline Water extracts & & & \\ NNGB & 43.24 \(\pm\) 4.64  & 25.93 \(\pm\) 1.67  & 10.34 \(\pm\) 3.05  & \\ FNGB & 44.24 \(\pm\) 1.45  & 23.35 \(\pm\) 1.19  & 11.77 \(\pm\) 2.33  & \\ NGB & 67.35 \(\pm\) 9.87  & 31.95 \(\pm\) 7.88  & 10.52 \(\pm\) 7.00  & 35.12 \(\pm\) 5.23  & 83.57 \(\pm\) 0.76  \\ \hline \hline \end{tabular}
\end{table}
Table 2: Scavenging effects of DPPH radicals by ethanol or water extracts of nonfermented-nongermination black soy milk, fermented-nongermination black soy milk, nonfermented-germination black soy milk, and fermented-germination black soy milk.  
Figure 4: Depigmenting effect of ethanol extracts from fermented-germination black soy milk on melanogenesis in zebrafish embryos in an in vivo phenotype-based system. Representative images of synchronized zebrafish embryos treated with ethanol extracts from fermented-germination black soy milk at 55 hpf (48 h treatment). Depigmenting efficacy of ethanol extracts of fermented-nongermination black soy milk in zebrafish embryos were photographed under stereomicroscope at the same magnification. PTU, phenylthiourea; hpf, h post fertilization. (**a**) Zebrafish embryos without treatment as a control, (**b**) 0.2 mM PTU as a standard positive control, (**c**) 250 \(\upmu\)g/mL, (**d**) 100 \(\upmu\)g/mL, (**e**) 50 \(\upmu\)g/mL, (**f**) 25 \(\upmu\)g/mL, and (**g**) 10 \(\upmu\)g/mL.  
Figure 3: Depigmenting effect of ethanol extracts from fermented-nongermination black soy milk on melanogenesis in zebrafish embryos in an in vivo phenotype-based system. Representative images of synchronized zebrafish embryos treated with ethanol extracts from fermented-nongermination black soy milk at 55 hpf (48 h treatment). Depigmenting efficacy of ethanol extracts from fermented-nongermination black soy milk on zebrafish embryos were photographed under a stereomicroscope at the same magnification. PTU, phenylthiourea; hpf, h post fertilization. (**a**) Zebrafish embryos without treatment as a control, (**b**) 0.2 mM PTU as a standard positive control, (**c**) 250 \(\upmu\)g/mL, (**d**) 100 \(\upmu\)g/mL, (**e**) 50 \(\upmu\)g/mL, (**f**) 25 \(\upmu\)g/mL, and (**g**) 10 \(\upmu\)g/mL.