Purification and bioactivity of fucoidan from kappaphycus alvarezii alga

Abstract

Kappaphycus alvarezii is a type of seaweed containing numerous carbohydrate with biological activities, especially fucoidan. About chemical aspect, fucoidan is fucose polysaccharides (FCSPs) with diverse biological activities including antioxidant, anticoagulant, anti-inflammatory, antiviral, antitumor... Fucoidan is found not only in brown algae but also in K. alvarezii alga from the central coast of Vietnam. In this study, fucoidan purification, fucoidan structure and biological activities of K. alvarezii alga (collected at Dam Mon area, Khanh Hoa province) were investigated. The yield recovery of two-stage precipitation by ethanol 99% was 84.4%. The protocol of fucoidan purification by ion-exchange chromatography was applied with tris-HCl buffer, elution solvent NaCl 1M; The yield was 60.99%. The structure of fucoidan from K. alvarezii was determined by 1H-NMN spectrum with the specific characteristic properties of fucoidan. The antioxidant activity of the purified fucoidan via IC50 was 303.51±0.12 μg/mL (DPPH assay), 299.97±3.12 μg/mL (ABTS essay). The purified fucoidan was shown better ability in cases of anti-coagulant, antibacterial activities than that of the crude extract. The anti-coagulation time of the purified fucoidan was 22.52 minutes. The minimum inhibitory concentrations (MICs) of the antibacterial activity (Bacillus cereus, Escherichia coli) were 400μg/mL. MICs was 500 μg/mL (Aspergillus flavus) and 600 μg/mL (Aspergillus niger).