Department of Food Science and Biotechnology, Graduate School, Kyungpook National University, Daegu, 41566, Korea.
Food and Bio-Industry Research Institute, Inner Beauty/Anti-Ageing Center, Kyungpook National University, Daegu, 41566, Korea.
Sci Rep. 2018 Sep 17;8(1):13928. doi: 10.1038/s41598-018-32303-7.
Medicinal plants have been used to treat diseases from time immemorial. We aimed to examine the efficacy of the ethyl acetate fraction of Nymphaea nouchali flower extract (NNFE) against melanogenesis process, and the underlying mechanisms in vitro and in vivo. Paper spray ionisation mass spectroscopy and (+) mode electrospray ionisation revealed the presence of seven flavonoids, two spermidine alkaloids, 3,4,8,9,10-pentahydroxy-dibenzo[b,d]pyran-6-one, and shoyuflavone C in NNFE. NNFE (100 µg/mL) significantly inhibited the monophenolase and diphenolase activities of mushroom tyrosinase at 94.90 ± 0.003% and 93.034 ± 0.003%, respectively. NNFE significantly suppressed cellular tyrosinase activity and melanin synthesis in vitro in melan-a cells and in vivo in HRM2 hairless mice. Furthermore, NNFE inhibited tyrosinase (TYR), tyrosinase-related protein (TYRP)-1, TYRP-2, and microphthalmia-associated transcription factor (MITF) expression, thereby blocking melanin synthesis. In particular, NNFE suppressed cAMP production with subsequent downregulation of CREB phosphorylation. Additionally, it stimulated MAP kinase phosphorylation (p38, JNK, and ERK1/2) and the proteasomal debasement pathway, leading to degradation of tyrosinase and MITF and the suppression of melanin production. Moreover, selective inhibitors of ERK1/2, JNK, and p38 attenuated NNFE inhibitory effects on melanogenesis, and MG-132 (a proteasome inhibitor) prevented the NNFE-induced decline in tyrosinase protein levels. In conclusion, these findings indicate that NNFE is a potential therapy for hyperpigmentation.
自古以来，药用植物就被用于治疗疾病。我们旨在研究睡莲花提取物的乙酸乙酯部分（NNFE）对黑色素生成过程的功效，并在体外和体内研究其潜在机制。纸喷雾电离质谱和（+）模式电喷雾电离显示 NNFE 中存在七种类黄酮、两种亚精胺生物碱、3,4,8,9,10-五羟基二苯并[b，d]吡喃-6-酮和酱油黄素 C。NNFE（100μg/mL）可显著抑制蘑菇酪氨酸酶的单酚酶和二酚酶活性，分别为 94.90±0.003%和 93.034±0.003%。NNFE 可显著抑制体外黑素瘤细胞和体内 HRM2 无毛小鼠的细胞酪氨酸酶活性和黑色素合成。此外，NNFE 可抑制酪氨酸酶（TYR）、酪氨酸酶相关蛋白 1（TYRP-1）、TYRP-2 和小眼畸形相关转录因子（MITF）的表达，从而阻断黑色素合成。特别是，NNFE 抑制 cAMP 产生，随后下调 CREB 磷酸化。此外，它还刺激 MAP 激酶磷酸化（p38、JNK 和 ERK1/2）和蛋白酶体降解途径，导致酪氨酸酶和 MITF 的降解以及黑色素生成的抑制。此外，ERK1/2、JNK 和 p38 的选择性抑制剂可减弱 NNFE 对黑色素生成的抑制作用，而 MG-132（蛋白酶体抑制剂）可阻止 NNFE 诱导的酪氨酸酶蛋白水平下降。综上所述，这些发现表明 NNFE 可能是一种治疗皮肤色素沉着过度的方法。
