Memory-Enhancing Effects of Silk Fibroin-Derived Peptides in Scopolamine-Treated Mice

Abstract

Although enzyme-hydrolyzed silk fibroin has been reported to enhance cognitive function before, it has been still unknown which peptides can improve memory. Here we report that amino acid sequences of three novel peptides were identified from fibroin hydrolysate. Fibroin hydrolysate was obtained by hydrolysis with protease after partial hydrolysis with 5M CaCl2. Synthesized peptides derived from these sequences improved scopolamine-induced memory impairments in mice. We confirmed this hydrolysate had effects that improved learning and memory abilities by performing the Rey-Kim test. From this hydrolysate of silk fibroin, amino acid sequences of eight peptides were identified by LC-MS/MS. Three peptides (GAGAGTGSSGFGPY, GAGAGSGAGSGAGAGSGAGAGY, and SGAGSGAGAGSGAGAGSGA) were synthesized to investigate whether they could improve memory. Passive avoidance test and Morris water maze test were performed, and all peptides showed memory-enhancing abilities on scopolamine-induced memory impairments in mice. In this study, we identified three novel peptides that could improve memory, and that silk fibroin hydrolysate was a mixture of various active peptides that could enhance memory.

Protective Effect of Boiled and Freeze-dried Mature Silkworm Larval Powder Against Diethylnitrosamine-induced Hepatotoxicity in Mice

“… 5 – 7 In this study, 100 mg/kg of DEN was injected and this dose was enough to induce cell death and initiate carcinogenesis in the liver. 33 The major goal of this study was to identify the hepatoprotective effect of BMSP because several silkworm byproducts have been shown to give a wide range of health benefits, such as blood glucose control, 18 – 20 improving male sexual function, 21 enhancing cognitive function, 22 , 23 and protection against alcoholic hepatotoxicity. 24 Because diet containing BMSP is enriched with diverse identified functional materials, such as silk fibroin proteins, flavonoids, polyphenols, vitamins, fatty acids, dietary fibers, and essential minerals, 22 it may have unidentified health improvement effects.…”

“…In addition to eating silkworm pupae, several important functional materials have been discovered in silkworm byproducts. Control of blood glucose concentrations has been shown to be induced by silk protein hydrolysate, 18 – 20 improvements in male sexual function have been shown to be induced by male silkworm pupal extracts, 21 enhancements in cognitive function have been shown to be induced by degraded silk fibroin proteins 22 , 23 and protection against alcoholic hepatotoxicity has been reported by silkworm excrement powder. 24 Recently, we have developed a technique for processing mature silkworm larvae that were formerly inedible because of the hardness of their silk glands.…”

Neuroprotective Function of a Novel Hexapeptide QMDDQ from Shrimp via Activation of the PKA/CREB/BNDF Signaling Pathway and Its Structure–Activity Relationship

“…The Morris water maze test, which assessed spatial learning and memory, was performed as previously described with modification. 20 The Morris water maze test (Institute of Materia Medica, Chinese Academy of Medical Sciences, Beijing, China) was carried out in a black plexiglass cuboid tank (73 × 42 × 20 cm) and was divided into four blind sides. mouse failed to find the platform within 120 s, it would be assisted with a plastic board and guided out of the maze.…”

Unlocking the biological potential of proteins from edible insects through enzymatic hydrolysis: A review

“…Inhibition of -glucosidase may currently be used to reduce intestinal uptake of glucose and subsequently lower post-prandial hyperglycemia in type 2 diabetics (Umpierrez et al, 2017). Animal studies describing the antihypertensive (Onsa-ard et al, 2013;Yuan, Wang, & Zhou, 2012), antioxidant (Sangwong, Sumida, & Sutthikhum, 2016;Yuan et al, 2012), antidiabetic (Han, Lee, Lee, Suh, & Park, 2016;Jung et al, 2010), memory enhancement (Kang, Lee, Kang, & Kang, 2013) and hypocholesterolemic (Lapphanichayakool, Sutheerawattananonda, & Limpeanchob, 2017) properties of silk protein hydrolysates have been reported. However, it appears that, to date, BAPs and protein hydrolysates derived from edible insects (other than B. mori), having bioactive properties in vitro and in small animals, have not been extensively studied in comparison to silk protein-derived peptides (Xia et al, 2013).…”