Table 2.

Protective effect and mechanism of brown algae-derived polysaccharides on intestinal health.

Source	Type	Inducer	Models	Function	References
Cladosiphon okamuranus Tokida	Fucoidan	H2O2	Caco-2 cells	Fucoidan remarkably reduced H2O2-induced paracellular permeability. Up-regulation of endogenous expression of claudin-1, claudin-2, and occludin in Caco-2 cells.	[15]
Acaudina molpadioides	Fucoidan	Cyclophosphamide (CPA)	Mice	Fucoidan intervention alleviates inflammation, increases tight junction protein expression, and increases the abundance of Coprococcus, Rikenella, and Butyricicoccus.	[54]
Laminaria japonica	Fucoidan	cefoperazone	Mice	Inhibiting the production of pro-inflammatory cytokines, restored the richness and diversity of intestinal microbiota, and improved the structural damage of intestinal mucosa.	[53]
Cladosiphon okamuranus	Fucoidan	-	Zebrafish	Down-regulation of the relative expression of the pro-inflammatory gene IL-1β.	[71]
Ascophyllum nodosum	Fucoidan	ciprofloxacin-metronidazole	Mice	Increased the abundance of Ruminococcaceae, and Akkermansia, and decreased the abundance of Proteus and Enterococcus; inhibited the overproduction of TNF-α, IL-1β, and IL-6, and promoted the expression of IL-10.	[28]
Sargassum fusiforme	Sulfated polysaccharide	-	-	In vitro fermentation increased the abundance of Faecalibacterium, Phascolarctobacterium, Bifidobacterium, and Lactobacillus.	[72]
Laminaria	Alginate	CPA	Mice	Up-regulation of tight junction protein expression reduced intestinal mucosal damage, decreased serum D-lactate and lipopolysaccharide concentrations, and downregulated toll-like receptor 4 (TLR4) and mitogen-activated protein kinase (MAPK) pathway expression to reduce intestinal inflammation.	[73]
Fucus vesiculosus	Fucoidan	LPS	RAW 264.7 Cell	Inhibited the secretion of NO, PGE 2 and TNF-α, IL-1β and reduced the production of intracellular reactive oxygen species.	[74]
Ascophyllum nodosum	Alginate	-	-	Promoted the growth of Bifidobacteria and Lactobacilli, increased levels of acetate and propionate.	[75]
Laminaria japonica	Alginate	-	-	Increased the abundance of Bacteroides.	[76]
Eisenia bicyclis	Laminaran	-	-	Inhibited ammonia, phenol, and indole production by human fecal microbiota and reduced indole levels in the cecum.	[77]
Ecklonia radiata	Polysaccharides	-	-	Increase in total bacteria, Bifidobacterium, Lactobacillus and increase in total SCFA, acetic and propionic acids.	[19]
Ecklonia cava	Fucoidan	LPS	Zebrafish	Inhibiting ROS and NO production induced by LPS treatment to alleviate inflammation.	[20]
Sargassum fusiforme	Fucoidan	Streptozotocin	Mice	Fucoidan significantly reduced fasting blood glucose, improved glucose tolerance, reduced oxidative stress in diabetic mice, and increased the abundance of beneficial intestinal microbes including Bacteroides, Faecalibacterium and Blautia.	[24]
Sargassum fusiforme	Fucoidan	High-fat diet	Mice	Fucoidan improves HFD-induced insulin resistance by activating the Nrf2 pathway, remodeling the intestinal microbiota, and reducing intestinal inflammation.	[25]
Laminaria japonica	Fucoidan	CPA	Mice	Fucoidan increased spleen and thymus indices, increased serum levels of IL-6, IL-1β, TNF-α, and IgG, and improved immunosuppression in mice. Increased the abundance of Lactobacillaceae and Alistipes, and decreased the abundance of Erysipelotrichia, Turicibacter, Romboutsia, Peptostreptococcaceae, and Faecalibaculum.	[78]
Ascophyllum nodosum	Fucoidan	ciprofloxacin-metronidazole	Mice	Dietary fucoidan prevented colon shortening and alleviated colon tissue damage by increasing the abundance of potentially beneficial bacteria (e.g., Ruminococcaceae_UCG_014 and Akkermansia) and decreasing the abundance of harmful bacteria (e.g., Aspergillus and Enterococcus), fucoidan also inhibited the overproduction of TNF-α, IL-1β, and IL-6 and promoted the expression of IL-10.	[28]
Fucus vesiculosus	Fucoidan	Sodium palmitate	HepG2 Cells Mice	Fucoidan significantly reduced the phosphorylation level of JNK and increased the phosphorylation of protein kinase B (pAkt). It improved hyperglycemia and serum insulin levels in mice with metabolic syndrome.	[31]
Undaria pinnatifida	Fucoidan	High-fat diet	Mice	Fucoidan reduces weight gain, fat accumulation and intestinal permeability in mice with metabolic syndrome. Intestinal Firmicutes and Bacteroidetes in fucoidan-treated high-fat diet mice were restored to normal levels and promoted the production of SCFAS and enhanced the expression level of IL-10.	[32]
Sargassum thunbergii	crude polysaccharide	-	-	Increased abundance of intestinal beneficial bacteria such as Bifidobacterium, Roseburia, Parasutterella, and Fusicatenibacter by in vitro fecal fermentation after 24 h of fermentation.	[79]
Laminaria japonica	Fucoidan	-	Mice	Increased in the abundance of Ruminococcaceae and Lactobacillu and decreased in the serum levels of lipopolysaccharide-binding protein.	[80]