Dunaliella salina-derived peptide protects from bone loss: Isolation, purification and identification

Abstract

Protein hydrolysates of Dunaliella salina (DSPH) were prepared and their potential antiosteopenic activity were determined in ovariectomized (OVX) Sprague-Dawley (SD) rats. Ultrafiltration, anion-exchange chromatography, and HPLC-ESI-MS/MS were used to isolate, purify, and identify the antiosteopenic peptides from DSPH. The antiosteopenic peptides were screened using molecular docking and zebrafish model. The results showed that DSPH can significantly improve the bone formation marker, bone mineral density and bone microarchitecture in OVX rats. A novel peptide with the sequence of ALVFQAQH (P32) was identified to be the potential active peptide that plays antiosteopentic activity, which can improve the stained integral optical density (IOD) and area in the larval skull of osteoporosis-like phenotypes zebrafish induced by Dexamethasone (Dex). This may be attributed to its physicochemical properties, such as low molecular weight, high hydrophobicity and the high proportion of antioxidant-related amino acids in its sequence, and ability to stimulate the mRNA expression of osteoblast-specific genes (Runx2α, ALP, OC) and antioxidant-related genes (Cu/Zn SOD and CAT). In conclusion, P32 could play a major role in antiosteopenic activity in DSPH, which could be a potential candidate for protecting from bone loss in osteoporosis.