Preparation, purification and identification of cadmium-induced osteoporosis-protective peptides from chicken sternal cartilage

Abstract Five novel peptides (GGAP, QIGPA, QLGPA, MPKYA and QGPAN) were identified from the purified sub-fraction (F1-c) of chicken sternal cartilage hydrolysate produced using alcalase (E/S 0.50%, pH 7.0, 55 °C, 9 h). The protective effect of the peptides was evaluated based on a cadmium-induced osteoporosis model (48 hr-LD 50 of 3.2 μM) by analyzing the cell viability, mitochondrial membrane potential (ΔΨm) and apoptosis rate. Except for MPKYA and GGAP, the other three identified peptides which contained the same GPA amino acid sequence showed favorable reversal effects with cell viability ranging from 62.93 to 90.96%, a significant increase of ΔΨm reaching more than 61.28% and a percentage of early apoptotic cells lower than 25.48% ( p