Bioactivity of Antheraea mylitta silk sericin: effect of the extraction process

Abstract

Bioresourcability is one of the important features for exploring natural biomaterials for sustained and continuous use in the field of medicine. Hence regeneration of silk proteins for various aspects of biomaterial application demands the extraction of silk proteins from silk filaments without compromising their natural properties. In the present study, sericin was extracted from A. mylitta cocoons by autoclave and alkaline method. The surface morphology and degumming ratio were studied to compare the extraction efficiency. The degumming ratio was found to be 13.3% for alkaline and 12.9% for autoclave process. The secondary structure conformations observed through FTIR revealed a higher percentage of α-helix in regenerated sericin of alkaline method (RSNa) and random coils in regenerated sericin of autoclave method (RSA). Total phenol and flavonoid contents of RSA was 618.33±2.27 mgGAE/10g and 472.31±0.63 mg QE/10g and that of RSNa was 521.57±1.18 mgGAE/10g and 449.74±0.57 mgQE/10g respectively. The IC50 value of antioxidant activity of RSNa was 2.84±0.174 mg/mL and RSA 0.995±0.13 mg/mL. Cytocompatibility assays were found to be higher in RSA than RSNa. Overall, regenerated sericin extracted from both methods revealed bioactive functionalities suitable for biomedical applications with RSA being advantageous over RSNa for its cost-effective, timesaving and chemical free extraction method.