Abstract:
Hibiscus syriacus is the national flower of South Korea and grows in varied climates range from
mild to tropical temperatures. In the Korean herbal medicine, the bark and roots of H. syriacus
have been used to cure diarrhea and bacterial infection, and its seeds were reported to effective
for fever and cold. Recently, native flowers of H. syriacus possessed promising potential as a
new edible colorant with various anthocyanins. In the current study, anthocyanin-rich extract of
two varieties of H. syriacus namely Pulsae and Paetanshim (PS and PTS, respectively) were
evaluated for, inhibition of melanin biogenesis. Results showed that PS and PTS did not strongly
downregulate mushroom tyrosinase activity in vitro; but significantly decreased the extracellular
and intracellular melanin production in B16F10 cells accompanied by the inhibition of α-
melanocyte-stimulating hormone (α-MSH)-induced microphthalmia-associated transcription
factor (MITF) and tyrosinase expression. It is also found that PS and PTS attenuated
pigmentation in α-MSH-stimulated zebrafish larva without any severe toxicity. Furthermore, PS
and PTS activated the phosphorylation of extracellular signal-regulated kinase (ERK) and a
specific ERK inhibitor, PD98059, which resulted in the recovery of intracellular and
extracellular melanin downregulation induced by PS and PTS in B16F10 cells and of
melanogenesis in zebrafish larvae. These findings suggest that anthocyanins from PS and PTS
inhibit melanogenesis in vitro and in vivo by activating the ERK signalling pathway.
