Diabetes is a metabolic disease characterized by persistent high blood sugar, resulting in dysfunction of pancreatic beta cells that secrete insulin, and gradual changes in the metabolism of carbohydrates, proteins, and fats, resulting in multiple complications. According to the International Diabetes Federation (IDF), 537 million adults between the ages of 20 and 79 worldwide suffer from diabetes, and current glucose-lowering drugs (e.g., biguidine and thiazolidinediones) are prone to side effects such as gas, vomiting and diarrhea. Therefore, natural plant-derived hypoglycemic active ingredients have been extensively studied. Seaweeds, the world's largest Marine organisms and Marine renewable resources, are roughly divided into three groups according to their colors, namely, brown, red and green chlorophyta.
The research status
Studies in the past decade have shown that whole seaweed has an anti-diabetic effect in human or animal models, but its effect is limited. It was mainly reflected in the inhibition of carbohydrate hydrolase (α -amylase and α -glucosidase) and dipeptidyl peptidase -IV (DPP-IV), and stable postpranpranal blood glucose level. In addition to inhibiting the enzyme in vitro, the researchers also focused on its hypoglycemic effects in mouse models. For example, The flavonoid-rich Enteromorpha plays a hypoglycemic role in streptozotocin induced diabetic male mice, which is mainly regulated by the PKB/Akt cell pathway. Secondly, multiple studies have shown that the beneficial effects of algae may be attributed to their protective effect on islet and recovery of insulin secretion of islet β cells, as well as promoting the proliferation of proteus, Babella and other beneficial bacteria in the intestinal tract to improve the composition of intestinal microbiota, thus regulating insulin release.
Algae are rich in bioactive compounds such as pigments, phenols and sulfated polysaccharides. These bioactive compounds also showed significant hypoglycemic effects.
(1) Fucoxanthin: Fucoxanthin is a carotenoid found in chloroplasts of algae. Its structure is characterized by propylene bonds and oxygen-containing functional groups, such as hydroxyl, carbonyl and carboxyl groups. Fucoxanthin's regulation of blood glucose level is the result of the improvement of insulin signaling pathway. Studies suggest that fucoxanthin may have a protective effect on hyperglycemia induced by obesity. At the same time, inhibit glucose induced oxidative stress, and jointly relieve a series of complications such as hyperglycemia.
(2) Tannins: Tannins belong to a group of polyphenols commonly identified and isolated from brown seaweed. The number of hydroxyl groups in tannins and the position of O bridge bond are closely related to their activity. Its hypoglycemic effects include: inhibition of carbohydrate hydrolase; Increasing skeletal muscle glucose uptake through the PKB/Akt cell pathway normalizes insulin levels and blood glucose, resulting in hypoglycemic effects. Reduce lipid oxidation level, improve antioxidant capacity; Protection against glucose - induced cell oxidation should be stimulated.
(3) Sulfated polysaccharide: Sulfated polysaccharide is mainly extracted from green algae and red algae, and its chemical structure, molecular weight and chain conformation are closely related to biological activity. Its hypoglycemic effects include: inhibition of carbohydrate hydrolase and anti-oxidation.
(4) Fucoidan: The framework of fucoidan is composed of α-(1→3) linked fucose, with a large number of sulfate and L-fucose groups at c-2 or C-4 position. Its hypoglycemic effects include: inhibition of carbohydrate hydrolase; By lowering fasting glucose levels, improving insulin levels, lipid and lipoprotein components, and antioxidant enzymes; By improving the intestinal flora, increasing the abundance of Bacteroidetes and Ackermanella, maintaining the stability of blood glucose.
Conclusion and Prospect
In summary, algae and its active substances such as fucoxanin, tannin and sulfated polysaccharides work in many ways to stabilize postpranpranal blood glucose levels without causing side effects. However, algae living in the sea can easily enrich cadmium, lead, chromium, copper and other heavy metals from the Marine environment, which makes the safety of raw materials to be determined. Although there are many studies on the anti-diabetes function of seaweed and its bioactive substances, there are great differences in the preparation and extraction process, and a standardized process is needed to prepare homogeneous extract. In addition, because different bioactive compounds have different toxicity and metabolic patterns, more statistically sound clinical sample studies are needed to validate their protective effects.
