Sulfated Glucuronorhamnoxylan from Capsosiphon fulvescens Ameliorates Osteoporotic Bone Resorption via Inhibition of Osteoclastic Cell Differentiation and Function In Vitro and In Vivo

Polysaccharides from Psoralea corylifolia seeds suppress osteoclastogenesis and alleviate osteoporosis

Psoralea corylifolia seeds, traditionally used in East Asia for their bone-strengthening properties, contain polysaccharides as one of their main components. However, the anti-osteoporotic potential of these polysaccharides remains underexplored. This study investigated the effects of polysaccharides extracted from P. corylifolia seeds (PCEP) on osteoclast differentiation and bone loss. PCEP effectively inhibited receptor activator of NF-κB ligand (RANKL)-induced osteoclast differentiation. Chemical composition analysis revealed that PCEP is predominantly composed of glucose and galactose, along with uronic acids. Mechanistically, PCEP suppressed the expression of c-Fos and NFATc1 transcription factors, key regulators of osteoclast differentiation, and significantly inhibited RANKL-induced phosphorylation of JNK, p38, and ERK MAPKs and the degradation of IκBα, pathways involved in the induction of c-Fos and NFATc1. This inhibition downregulated osteoclast-specific marker genes, including Atp6v0d2, DC-STAMP, and CtsK. In an ovariectomized mouse model of estrogen deficiency, PCEP administration mitigated bone loss and reduced body weight gain and fat accumulation. These findings indicate that PCEP is a bioactive polysaccharide capable of inhibiting osteoclast differentiation and ameliorating bone loss associated with estrogen deficiency, highlighting its potential as a novel therapeutic agent for postmenopausal osteoporosis.

Anti-inflammatory potential of ulvan

Green seaweeds are a widespread group of marine macroalgae that could be regarded as biorenewable source of valuable compounds, in particular sulfated polysaccharides like ulvans with interesting biological properties. Among them, anti-inflammatory activity represents an interesting target, since ulvans could potentially avoid side effects of conventional therapies. However, a great variability in ulvan content, composition, structure and properties occurs depending on seaweed specie and growth and processing conditions. All these aspects should be carefully considered in order to have reproducible and well characterized products. This review presents some concise ideas on ulvan composition and general concepts on inflammation mechanisms. Then, the main focus is on the importance of adequate selection of extraction, depolymerization and purification technologies followed by an updated survey on anti-inflammatory properties of ulvans through modulation of different signaling pathways. The potential application in a number of diseases, with special emphasis on inflammaging, gut microbiota dysbiosis, wound repair, and metabolic diseases is also discussed. This multidisciplinary overview tries to present the potential of ulvans considering not only mechanistic, but also processing and applications aspects, trusting that it can aid in the development and application of this widely available and renewable resource as an efficient and versatile anti-inflammatory agent.

Metabolic bone disorders and the promise of marine osteoactive compounds

Metabolic bone disorders and associated fragility fractures are major causes of disability and mortality worldwide and place an important financial burden on the global health systems. These disorders result from an unbalance between bone anabolic and resorptive processes and are characterized by different pathophysiological mechanisms. Drugs are available to treat bone metabolic pathologies, but they are either poorly effective or associated with undesired side effects that limit their use. The molecular mechanism underlying the most common metabolic bone disorders, and the availability, efficacy, and limitations of therapeutic options currently available are discussed here. A source for the unmet need of novel drugs to treat metabolic bone disorders is marine organisms, which produce natural osteoactive compounds of high pharmaceutical potential. In this review, we have inventoried the marine osteoactive compounds (MOCs) currently identified and spotted the groups of marine organisms with potential for MOC production. Finally, we briefly examine the availability of in vivo screening and validation tools for the study of MOCs.