Exploration of an efficient and universal extraction strategy for fucoidan with glycolipid-lowering activity from typical brown algae: The importance of ball milling combined with acid treatment

Abstract

Fucoidan possesses a variety of biological activities beneficial for human wellness. It is a good candidate for ameliorating obesity and diabetes. However, high-purity fucoidan products are limited due to the co-extraction of impurities i.e. alginate, protein and small molecular substances. In this study, the optimal preparation strategy for high-purity fucoidan from a template brown alga (Saccharina japonica) was screened out by the exploration of key and auxiliary steps. The key step was confirmed as moderate-temperature acid extraction and the auxiliary steps were fixed on ethanol refluxing and ball milling pretreatment. The fucose content of S. japonica fucoidan increased by 7.15 times and the sulfate group content increased by 4.87 times compared with those of fucoidans prepared by classic high-temperature acid extraction. Ball milling-assisted moderate-temperature acid extraction performed great effectiveness and universality in the extraction of high-purity fucoidans derived from four brown algae including S. japonica, Undaria pinnatifida, Sargassum fusiforme, and Fucus vesiculosus. Glycolipid-lowering activities of four fucoidans were confirmed by their interactions with intestinal bile acid, cholesterol micellar, glucose and probiotics including butyrate-producing bacteria, Bacteroides, Bifidobacterium, and Lactobacillus. Our study provided an efficient and universal extraction process for high-purity fucoidan with glycolipid-lowering activity from typical brown algae.