Atheroprotective effect of novel peptides from Porphyridium purpureum in RAW 264.7 macrophage cell line and its molecular docking study

Objective To explore the atherogenic foam cell prevention efficiency of two dipeptides purified from Porphyridium purpureum on RAW 264.7 cell line and to study its molecular interaction through molecular docking. Result P. purpureum consists of 29.9% protein and 2.98% phycoerythrin on a dry weight basis. The two dipeptides namely of Histidine–Glutamic acid (HE) and Glycine–Proline (GP) isolated from the total protein and purified phycoerythrin of P. purpureum respectively, were evaluated for atherogenic foam cell prevention capacity in RAW 264.7 cell line. The IC 5O values of peptides were found to be 91.2 ± 1.81 µg/ml (GP), 103.3 ± 4.8 µg/ml (HE) in MTT assay. The two peptides reduce the foam cell formation, intracellular lipid accumulation (cholesterol and triglycerides) and the secretion of TNF-α and IL-6 which are inflammatory cytokines in RAW 264.7 cell line at non-cytotoxic concentrations. A molecular interaction study proposed the binding pose for GP and HE peptides targeting the scavenging receptors CD36, SRA1, and Map Kinase p38 (a protein mediator). Conclusions The cell line and molecular docking study indicated that among the two dipeptides, peptide GP has the highest atherogenic foam cell prevention efficiency.