The anti-angiogenic, anti-inflammatory and anticoagulant potential of a polysaccharide extracted from the brown alga Cystoseira humilis

• Approximately 5.44% (w/w) crude polysaccharide, designated PSCH, was extracted from Cystoseira humilis; • SEC analysis showed that the molecular weight of the extracted PSCH was 379.44 kDa; • FT-IR, HPLC-RID, SEM and XRD revealed the structural properties of the polysaccharides; • PSCH significantly inhibited angiogenesis in the chorioallantoic membrane (CAM) assay model; • PSCH showed anti-inflammatory activity similar to that of diclofenac in vivo ; • PSCH can inhibit both intrinsic and extrinsic coagulation pathways. The present study aimed to evaluate the properties of a sulfated polysaccharide (PSCH) extracted from the brown alga Cystoseira humilis . We analyzed the chemical composition, anti-angiogenesis activities, anticoagulant, and anti-inflammatory effects of the PSCH, using various techniques encompassing UV–visible spectroscopy, fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (X-RD), scanning electron microscopy (SEM), steric exclusion chromatography (SEC) and high-performance liquid chromatography coupled to refractive index detector (HPLC-RID). The study found that PSCH was a sulfated heteropolysaccharide consisting of glucuronic acid, arabinose, galacturonic acid, xylose and fructose, and has a semi-crystalline nature with a molecular weight of about 379.44 kDa. The PSCH contains 41.77 % carbohydrates, 12.33 % proteins, and 4.59 % sulfates. The PSCH fraction has anti-angiogenic potential highlighted through assays on the chorioallantoic membrane, where vascular branching was inhibited by about 41.65 % and 61.38 % at concentrations of 50 and 100 μg/egg, respectively, compared to the untreated group. PSCH displayed an anti-edematous effect in vivo by reducing malondialdehyde and advanced oxidation protein products in paw tissue after five hours of carrageenan injection. When rats were co-treated with PSCH, there was evidence of a significant increase in antioxidant enzyme activity (superoxide dismutase, glutathione peroxidase, and glutathione) in edematous paw tissues compared to untreated rats. Furthermore, PSCH significantly influenced hematological parameters and the rate of anti-inflammatory serum protein fractions compared to the inflamed group. Interestingly, PSCH may exhibit anticoagulant properties by extending activated partial thrombosis time, thrombin time and prothrombin time. The present study has shown that Cystoseira humilis polysaccharides have antioxidant, anti-angiogenic, anti-inflammatory, and anti-coagulant properties, making them suitable for therapeutic purposes.