Sericin, a Versatile Protein from Silkworm - Biomedical Applications

Abstract

The silkworm, Bombyx mori, which feeds solely on the leaves of the mulberry plant, produces mulberry silk. The components of Bombyx mori silk are 60-80 percent fibroin, 15-35 percent sericin and 1-5 percent non-sericin, including wax, pigments, sugars and other impurities. Silk sericin is a natural polymer that encloses and holds together two filaments of fibroin in the silk thread used in the cocoon. In the research and production of medical biomaterials and biomedicines, protein-based silk fibroin has been widely used for two decades. Sericin is often neglected and abandoned in the manufacturing of traditional silk fabrics, silk floss or synthetic silk biomaterials as a by-product or waste. However, sericin is not only a highly useful biological substance, but also has a great deal of biological activity, similar to fibroin. General characteristics of both silk proteins, fibroin and sericin, extracted from Bombyx mori silkworm, and the biological activity and possible use of sericin were addressed in this review. Due to its amino acid make-up and antioxidant properties, sericin has been used in the food and cosmetic industry. The moisturizing power provides guidance for wound healing as a therapeutic agent, protection against ultraviolet radiation, and formulation of creams and shampoos. Antioxidant activity associated with low sericin digestibility, which increases application in the medical field, such as antitumor, antimicrobial and anti-inflammatory agent, anticoagulant, works in the health of the colon, enhances constipation and, by improving plasma lipid profile, protects the body from obesity. In addition, the properties of sericin allow its application in tissue engineering and drug delivery as a culture medium and cryopreservation, demonstrating its efficient use as an essential biomaterial.