![]() ![]() By using all the above-mentioned methods, yellow-green sericin indicated higher values. The yellow-green and white sericin proteins indicated high antioxidant activity wherein the activity of white sericin protein was higher than that of yellow-green sericin protein although there was no significant difference. ![]() Measurement of hydroxyl radical scavenging activity by the ESR methodAs shown in, the hydroxyl radical scavenging activity was measured by the ESR method. Particularly, the value of yellow-green sericin protein (29.3 mmol Trolox eq./100 g) was significantly higher than that of the white sericin protein (10.0 mmol Trolox eq./100 g) (p. ![]() It has been reported by Yamaguchi et al that peroxyl radical eliminating activities of burdock, ginger, and komatsuna (Japanese mustard spinach) were 7.5, 4.8, and 12.3 mmol Trolox eq./100 g, respectively, and the activity of kamaboko was also reported by Harada et al as 0.166 mmol Trolox eq./100 g. Fluorescein sodium salt was purchased from Sigma-Aldrich Japan (Tokyo, Japan), and 6-hydroxy-2,5,7,8-tetramethyl-chroman-2-carboxylic acid (Trolox) was purchased from Tokyo Kasei Kogyo Co., Ltd. ChemicalsDPPH, tris (hydroxymethyl) aminomethane (Tris), 2,2′-Azobis (2-amidinopropane) dihydrochloride (AAPH), potassium dihydrogenphosphate (KH 2PO 4), dipotassium hydrogenphosphate (K 2HPO 4), ethanol (99.5%), methanol (HPLC grade), hydrochloric acid, sodium dihydrogenphosphate (NaH 2PO 4), disodium hydrogenphosphate (Na 2HPO 4) and sodium tetraborate were purchased from Wako Pure Chemical Industries, Ltd. Furthermore, we examined whether or not the antioxidant activity of bread was elevated by the addition of sericin protein. In this study, we investigated the antioxidant activities of different types of sericin proteins extracted from the shell of the cocoon, designated hereafter as white sericin protein and yellow-green sericin protein, using the 1,1-Diphenyl-2-picrylhydrazyl (DPPH), chemiluminescence, ORAC and ESR methods. Among different colored cocoons, yellow-green cocoon shells contain various flavonol compounds with antioxidant activity. The color components coexist and accumulate in the sericin layer of cocoons. Zhaorigetu et al demonstrated that sericin protein exerts a suppressant effect on skin cancer and colon cancer, while Li et al demonstrated a protective effect of sericin and sericin peptide against alcohol-induced liver and gastric injuries in mice (,). Additionally, recent studies have focused on the antioxidative activity of seafood using oxygen radical absorbance capacity (ORAC), hydroxyl radical averting capacity (HORAC) and electron spin resonance (ESR) methods (,).By contrast, Dash et al showed that sericin protein from silkworm inhibited UVB-induced apoptosis in human skin keratinocytes, and that the antioxidant potential of the protein against hydrogen peroxide-induced oxidative stress in skin fibroblasts using the indicators of catalase, lactate dehydrogenase and malondialdehyde activities. Lipid oxidation on vegetable oil and frying oil using the indicators peroxide value (POV), carbonyl value (COV) and anisidin value (AnV) has been previously identified (,). Notably, during the production of silk cloth, the sericin protein is discarded.In a previous study, we reported the dyeing property of silkworm cocoon (,). Silk emitted by the silkworm consists of two main proteins, sericin and fibroin, with fibroin being the structural center of the silk, and sericin being the sticky material surrounding it. ![]() By contrast, a higher antioxidative property was determined in white sericin protein by the ESR method. A comparison of the two types of sericin proteins revealed that yellow-green sericin protein exhibited high antioxidative properties as indicated by the DPPH, chemiluminescence and ORAC methods. High antioxidative properties of sericin proteins were indicated by all four methods. The antioxidative properties were measured in sericin proteins extracted from the shell of the cocoon, designated hereafter as white sericin protein and yellow-green sericin protein, as well as bread without sericin protein and bread to which white sericin powder had been added using four measurement methods: 1,1-Diphenyl-2-picrylhydrazyl (DPPH), chemiluminescence, oxygen radical absorbance capacity (ORAC) and electron spin resonance (ESR). In this study, we focused on the antioxidative properties of sericin proteins. Recent efforts have focused on the use of sericin proteins extracted from cocoons of silkworm as a healthy food source for human consumption. ![]()
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