Scholarlink

<p>The aim of this study was to develop a bioactive keratin-based nanocomposite for modulation of tyrosinase structure and function. Keratin nanoparticles (KNPs) were synthesized from ostrich feathers and functionalized with <i>Diospyros lotus</i> leaf extract (DLE). Physicochemical analyses (XRD, FT-IR, <i>ζ</i>-potential, DLS, TEM) confirmed a stable surface-functionalized nanocomposite, evidenced by a <i>ζ</i>-potential shift from − 16.9 mV to -40.9 mV and increased particle sizes (TEM: 87.1 to 113.3&#xa0;nm; DLS: 275.3 to 325.2&#xa0;nm). DLE-KNPs exhibited dose-dependent inhibition of mushroom tyrosinase with an IC<sub>50</sub> of 0.077&#xa0;mg/mL. Kinetic evaluation revealed a mixed-type inhibitory mechanism, supported by fluorescence quenching (<i>K</i><sub>A</sub>=1.83 mL/mg). Far-UV CD spectroscopy showed a reduction in α-helical content (14.1% to 10.2%) with increased β-sheet (33.9% to 35.3%) and random coil (35.0% to 39.8%), indicating conformational modulation without global unfolding. Cellular evaluation on A-375 melanoma cells showed excellent biocompatibility at low doses (≤ 50&#xa0;µg/mL; &gt;90% viability) and an IC<sub>50</sub> of approximately 300&#xa0;µg/mL for the composite, compared to 230&#xa0;µg/mL for free DLE extract. Flow cytometry revealed that DLE-KNPs induced 44.6% total apoptosis at 300&#xa0;µg/mL (predominantly early apoptosis), while free DLE extract caused 54% apoptosis and bare KNPs 18.5%. Overall, this study identifies DLE-KNPs as a natural, mechanistically well-defined nano-bio platform with potential for modulating tyrosinase conformation and melanogenic activity, while simultaneously providing preliminary antiproliferative activity against melanoma cells.</p> Graphical Abstract <p></p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Tyrosinase Structural Perturbation and Functional Inhibition by an Ostrich-Derived Keratin-Diospyros lotus Nanobiocomposite: Biochemical Mechanism and Melanoma Cell Response

  • 期刊论文

  • 发表日期：

    2026年7月14日

查看全文
  • Marzieh Karimian Amroabadi,
  • Azadeh Hekmat,
  • Asghar Taheri-Kafrani,
  • Aghdas Banaei

摘要

The aim of this study was to develop a bioactive keratin-based nanocomposite for modulation of tyrosinase structure and function. Keratin nanoparticles (KNPs) were synthesized from ostrich feathers and functionalized with Diospyros lotus leaf extract (DLE). Physicochemical analyses (XRD, FT-IR, ζ-potential, DLS, TEM) confirmed a stable surface-functionalized nanocomposite, evidenced by a ζ-potential shift from − 16.9 mV to -40.9 mV and increased particle sizes (TEM: 87.1 to 113.3 nm; DLS: 275.3 to 325.2 nm). DLE-KNPs exhibited dose-dependent inhibition of mushroom tyrosinase with an IC50 of 0.077 mg/mL. Kinetic evaluation revealed a mixed-type inhibitory mechanism, supported by fluorescence quenching (KA=1.83 mL/mg). Far-UV CD spectroscopy showed a reduction in α-helical content (14.1% to 10.2%) with increased β-sheet (33.9% to 35.3%) and random coil (35.0% to 39.8%), indicating conformational modulation without global unfolding. Cellular evaluation on A-375 melanoma cells showed excellent biocompatibility at low doses (≤ 50 µg/mL; >90% viability) and an IC50 of approximately 300 µg/mL for the composite, compared to 230 µg/mL for free DLE extract. Flow cytometry revealed that DLE-KNPs induced 44.6% total apoptosis at 300 µg/mL (predominantly early apoptosis), while free DLE extract caused 54% apoptosis and bare KNPs 18.5%. Overall, this study identifies DLE-KNPs as a natural, mechanistically well-defined nano-bio platform with potential for modulating tyrosinase conformation and melanogenic activity, while simultaneously providing preliminary antiproliferative activity against melanoma cells.

Graphical Abstract