Osteogenic activities of four calcium‐chelating microalgae peptides

Abstract

BACKGROUND: Adequate calcium intake is necessary to prevent osteoporosis, which poses significant public health challenges. The natural bioactive peptide calcium chelates have been regarded as superior calcium supplements. Microalgae peptides are regarded as potential candidates for protection from bone loss in osteoporosis. This study aimed to prepare microalgae calcium-chelating peptides from four microalgae proteins and assess their osteogenic activities in osteoporosis-like zebrafish. RESULTS: After in vitro gastrointestinal digestion, 4.42% Chlorella pyrenoidosa protein, 2.74% Nannochloropsis oceanica protein, 6.07% Arthospira platensis protein and 10.47% Dunaliella salina protein were retained. The calcium-chelating capacities of four microalgae protein hydrolysates (MPHs) ranged from 14.10 ± 7.16% to 34.11 ± 9.34%. CaCl 2 addition increased the maximum absorption peaks, absorption intensities and particle sizes of MPHs. Calcium-chelating MPHs showed stronger osteogenic activities than MPHs in the osteoporosis-like zebrafish model, with significantly increased mineralized tissue area and integrated optical density.CONCLUSION: Microalgae proteins have favorable digestibilities. Among the four MPHs, Nannochloropsis oceanica protein hydrolysates showed the highest calcium-chelating capacity, which might be due to its high degree of hydrolysis after in vitro digestion and high content of Ser, Tyr, Thr, Asp and Glu. The absorption intensities and particle sizes of MPHs both increased after calcium addition. MPH treatment could reverse dexamethasone-induced osteoporosis of zebrafish, and MPHs-Ca chelates showed higher osteogenic activities in osteoporosis-like phenotype zebrafish.

Calcium absorption by Alaska pollock surimi protein hydrolysate promotes osteoblast differentiation

“…Chen et al (2014) showed that hydrolysis of tilapia scale protein generated calcium absorption-enhancing peptides with a greater calcium-binding capacity than did trypsin-treated neck after digestion with pepsin, consistent with our results. In a comparative study of the protein hydrolysis and calcium-binding capacity of four types of microalgae (Yu et al, 2022), the DH and calcium-binding capacity increased when the microalgae were digested using both pepsin and trypsin compared to pepsin alone. To determine the effect of the molecular weight of the hydrolysate on the calcium-binding ability, we fractionated the hydrolysate using ultrafiltration membranes and then measured the calcium-binding ability.…”

Anti‐osteoporosis effects of mammalian lignans and their precursors from flaxseed and safflower seed using zebrafish model

“…When the fish larvae are stained with calcein, the backbone could be observed as green fluorescence (Dubale et al., 2022; Peng et al., 2019). Zebrafish models are increasingly being used to evaluate the anti‐osteoporosis effect of food ingredients (Caro et al., 2016; Wu et al., 2022; Yu et al., 2022).…”