Synechococcus marine microalgae peptide: Melanogenesis inhibition in cellular and zebrafish models

Abstract

In this study, the AILQSYSAGKTK (named AK-12) peptide, also known as AK-12, from the Synechococcus marine microalgae cell extract is examined to determine the mechanism by which tyrosinase inhibition takes place. According to the docking simulation, it is expected that the peptides bind and interact at the tyrosinase active site, with the potential to support the inhibition of tyrosinase. For testing, the required peptides were first synthesized, before the results revealed tyrosinase inhibitory activity for which the respective IC50 values for mono- and di-phenolase activities were 489.71 ± 0.01 μM, and 765.57 ± 0.01 μM. The characteristics of the different competitive types were shown in a Lineweaver-Burk plot. For the treatment of B16F10 cells, peptide concentrations of 50–400 μM were selected, confirming the absence of cytotoxicity. When the peptide was introduced, both tyrosinase activity and the production of melanin were significantly inhibited. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was then used to assess the suppression of melanin synthesis in MITF (microphthalmia-associated transcription factor, TYR (tyrosinase), TRP-1 (tyrosinase-related protein-1) and TRP-2 (tyrosinase-related protein-2). An in vivo toxicity assay was also carried out to evaluate zebrafish embryo cell death, revealing that AK-12 did not significantly affect cell death, while strong anti-melanogenic activity was observed for the concentration of 50 μM. From these findings it could be concluded that the peptide in question may offer potential in future hyperpigmentation treatments.