Kumar Jadi Praveen, Mandal Biman B
Biomaterial and Tissue Engineering Laboratory, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati (IITG), Guwahati 781039, Assam, India.
Biomaterial and Tissue Engineering Laboratory, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati (IITG), Guwahati 781039, Assam, India.
Free Radic Biol Med. 2017 Jul;108:803-818. doi: 10.1016/j.freeradbiomed.2017.05.002. Epub 2017 May 2.
Sericin, a principal constituent of silk, is widely used in various biomedical applications. In addition, conferring protection against free radicals and oxidative damage add more value to its therapeutic potential. However, the antioxidant (AO) properties of silk sericin (SS) remains contingent on extraction procedures. In the present study, we have evaluated the effect of different extraction methods (conventional, autoclaving, urea, alkali and acid-degradation) on AO properties of SS from three Indian silk varieties [Antheraea assamensis (AA), Philosamia ricini (PR) and Bombyx mori (BM)]. The physico-chemical characterization studies revealed that the molecular weight of SS isolates of each method ranged from 10 to 220kDa along with varied protein structural biochemistry. SS extracts using urea-degradation (BM, PR and AA), conventional method and alkali-degradation (BM) displayed high percentage of β-sheets, random coils and turns. Acid-degraded SS (PR, followed by AA and BM) showed the highest total flavonoid content while conventional method (PR), autoclaving (AA) and alkali-degradation (BM) displayed lowest flavonoid levels. Interestingly, SS extracted by autoclaving (BM and AA), acid-degradation (PR), conventional and alkali-degradation (BM, AA and PR) methods exhibited 50% reduction of 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical. Moreover, the efficacy of antioxidant potential of SS extracted by different methods was found to be in the order of "alkali>autoclaving>conventional" as demonstrated in L929 cells. Correspondingly, the anti-lipid peroxidation activity of SS extracted by alkali method (AA, BM and PR) further confirmed better AO properties amid others. Thus, the present study demonstrates that the extraction methods may significantly affect AO activity of SS which might be of importance for potential cosmetic applications.
丝胶是蚕丝的主要成分，广泛应用于各种生物医学领域。此外，它具有抗自由基和氧化损伤的特性，这进一步提升了其治疗潜力。然而，丝胶（SS）的抗氧化（AO）性能仍取决于提取方法。在本研究中，我们评估了不同提取方法（传统法、高压灭菌法、尿素法、碱法和酸降解法）对来自三种印度丝绸品种[阿萨姆柞蚕（AA）、蓖麻蚕（PR）和家蚕（BM）]的SS的AO性能的影响。物理化学表征研究表明，每种方法提取的SS分离物的分子量在10至220 kDa之间，且蛋白质结构生物化学各不相同。采用尿素降解法（BM、PR和AA）、传统方法和碱降解法（BM）提取的SS提取物显示出较高比例的β-折叠、无规卷曲和转角。酸降解的SS（PR，其次是AA和BM）总黄酮含量最高，而传统方法（PR）、高压灭菌法（AA）和碱降解法（BM）的黄酮含量最低。有趣的是，采用高压灭菌法（BM和AA）、酸降解法（PR）、传统法和碱降解法（BM、AA和PR）提取的SS使2,2-二苯基-1-苦基肼（DPPH）自由基减少了50%。此外，如在L929细胞中所示，不同方法提取的SS的抗氧化潜力功效顺序为“碱法>高压灭菌法>传统法”。相应地，碱法提取的SS（AA、BM和PR）的抗脂质过氧化活性进一步证实了其在其他方法中具有更好的AO性能。因此，本研究表明提取方法可能会显著影响SS的AO活性，这对于潜在的化妆品应用可能具有重要意义。
