Identification and structure-activity modeling of ACE inhibitory peptides demonstrating anti-inflammatory effects: Extracted from Antheraea assama and Philosomia ricnii pupae

Abstract

Traditionally edible silkworm pupae abundantly available in North eastern region of India have a notable protein content and comprises vast scope of bioactive peptides with unrevealed possibilities. Therefore, in this study, peptides derived from Muga and Eri pupae with highest potential to inhibit ACE (Angiotensin converting enzyme) and scavenge free radicals have been characterized, followed by understanding molecular interaction mechanism behind inhibition action and anti-inflammatory potential in endothelial model. This study was proposed to generate most potent purified chromatography fractions comprising ACE-inhibitory peptides, identified to contain total 105 peptides in fraction F4 and 53 peptides in fraction F6, majorly acquired from haemolymph protein in pupae. 96 peptides with length 5–12 amino acids were selected and exposed to peptide-ACE interaction by molecular docking and simulation. Among top 15 peptides, LTSDRDFYVSK, VIELPYGVENR and IYVSDQY acted as effective competitive ACE inhibitor, peptide QTLVPFMK indicated its non-competitive inhibition. Fraction F4 and F6 remarkably alleviated COX-2, iNOS expression along with NO release, IL-6 (interleukin-6), IL-1β (interleukin-1 beta) and TNF-α (Tumor necrosis factor-alpha) generation. Additionally, peptide fractions showed significant potential to curb elevated free radical concentration and induced endogenous antioxidant enzymes expression. This conveyed that Muga and Eri pupae protein derived peptide fractions certainly carried an effective role in modulating the cross talk between ACE activity and inflammation mechanisms, supporting their therapeutic potency.