Antioxidant, anti-inflammatory, α-amylase inhibitory, and thrombolytic properties of proteins derived from the edible pupae of the eri silkworm (<i>Samia ricini</i>): a potential source of functional foods

Abstract Samia ricini is a silkmoth cultivated for the production of eri silk. Its edible pupae are a component of the traditional diet of various communities. The present study aimed to evaluate the beneficial properties of protein extract of S. ricini pupae (PESRP) in vitro and in vivo. PESRP showed significant free radical scavenging activity of 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) (IC50 86.9 ± 2.5 μg/ml) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) (IC50 372.5 ± 4.2 μg/ml) radicals; lower Fe3+ and Cu2+ chelating activities than ascorbic acid (AA) but higher than butylated hydroxytoluene (BHT) assessed through ferric ion reducing antioxidant power (FRAP) and total antioxidant capacity assays; significant in vitro anti-inflammatory efficacy assessed by egg albumin denaturation inhibition and lipoxygenase (LOXs) inhibition assays; and significant alpha-amylase inhibition and thrombolytic efficacies in vitro. PESRP also significantly reduced inflammation and oxidative stress in mouse paw edema induced by carrageenan, in vivo. Administration of PESRP did not increase serum IgE levels in comparison to control mice. Moreover, peptide sequencing by LC–MS/MS revealed the presence of a high percentage of amino acids with free radical scavenging properties in PESRP. Taken together, this study indicates that the proteins extracted from the edible pupae of S. ricini have health benefits as natural antioxidant and anti-inflammatory agents, with potential applications in diabetes control and blood clot lysis.