A novel peptide purified from the fermented microalga Pavlova lutheri attenuates oxidative stress and melanogenesis in B16F10 melanoma cells

A novel peptide was purified from marine microalga, Pavlova lutheri fermented by yeast Hansenula polymorpha, and its protective effect against oxidative stress as well as inhibitory effect on melanogenesis was investigated. The purified peptide has a molecular mass of 526 Da and its amino acid sequence was determined as Met-Gly-Arg-Tyr by Q-TOF mass spectroscopy. The purified peptide scavenged DPPH, hydroxyl radicals and hydrogen peroxide (H2O2) at the IC50 values of 0.285, 0.068 and 0.988 mM, respectively. Intracellular reactive oxygen species (ROS) induced H2O2 was attenuated by addition of the purified peptide. The purified peptide demonstrated inhibitory properties against alpha-MSH-induced melanogenesis via melanin content and tyrosinase (TYR) inhibition in B16F10 melanoma cells. We also found that the purified peptide decreased melanogenesis-related proteins; microphthalmia-associated transcription factor (MITF) and TYR protein expressions. Moreover, the purified peptide activated extracellular signal-regulated kinase (ERK) but not that of c-Jun N-terminal kinase (INK) and p38 mitogen-activated protein kinase (MAPK). A specific ERK inhibitor significantly blocks the purified peptide-inhibited melanin synthesis and TYR activity. Hence, these results indicated that the purified peptide isolated from P. lutheri has potential whitening effects and prominent protective effects on oxidative stress-induced cell damages, which might be used in pharmaceutical and cosmeceutical industries. (C) 2015 Elsevier Ltd. All rights reserved.