FISHERIES RESEARCH INSTITUTE,MOA,TAIWAN

The maintenance of bones is referred to as the "bone remodeling cycle," which has two components: osteogenesis and bone loss. On the other hand, E. serra is an abundant source of calcium and phytochemicals in Taiwan that is used as an edible algal raw material. This study aims to investigate the mechanism and enzymatic hydrolysis of E. serra for the development of bone healthcare products. We discovered that 100 grams of E. serra contains 1.3 ± 0.06 g of calcium, which is sufficient to meet the daily calcium needs of humans, and that 23.11 ± 0.08 g of sulfated polysaccharide can promote osteogenesis in a synergistic manner. When 0.625 mg/ml E. serra hydrolyzate was added to the maturation of osteoblasts (MG-63), the type I procollagen and alkaline phosphatase levels increased by 154.36% (p < 0.05) and 164.43% (p < 0.05), respectively. Which demonstrated that E. serra hydrolyzate can promote osteoblast maturation and mineralization. In addition, it was confirmed that 250-500 µg/ml E. serra hydrolyzate down-regulated the mRNA expression of genes related to osteophyte maturation and differentiation, including RANK, NFATc1, and DC-STAMP, which were 0.11-0.06; 0.24-0.10; and 0.75-0.50 in the control group. In addition, nuclear staining revealed that it inhibited the formation of mature multinucleated osteophytes and exhibited a dose-dependent inhibition of cell TRAP activity. BCL-2 and BAX mRNA expression were 0.45-fold and 2.91-fold of the control group, respectively. This variant demonstrated that E. serra hydrolyzate mitigates bone loss by promoting osteoblast apoptosis and inhibiting the decomposition of calcium minerals in the bone matrix. In ovarian removal animal experiments, after 6 weeks of continuous administration of 500 mg/kg/day E. serra hydrolyzate, the B-ALP content (0.19 ± 0.03 ng/ml) increased and the NTx content (4.69 ± 1.80 μmol/ml) decreased in the serum of test rats, indicating that E. serra hydrolyzate promoted bone formation and prevented bone loss. Also, the femoral bone mineral density, trabecular bone thickness, and trabecular bone area ratio of rats were found to be slightly or significantly greater than those of the control solution group, just as Fosamax PLUS did. In addition, genotoxicity testing revealed that E. serra hydrolyzate and its metabolites were not mutagenic, and the median lethal dose (LD50) for acute oral toxicity was greater than 1 g/kg BW. Based on all available data, the recommended daily adult dose of E. serra hydrolyzate is 4.8 g.