In the pathogenesis of Type I and Type II Diabetes mellitus, oxidative stress plays a vital role. Oxidative stress condition arises when the production of oxidant exceeds the antioxidant activity in cells and plasma. This oxidant excess is due to two important mechanisms:
1. Free radicals overproduction from the mitochondria and
2. Cellular NADPH oxidase activation via Angiotensin II receptors.
Free radicals are chemicals species with its outer orbital having an unpaired electron. They include peroxides, superoxides and hydroxyl radical. In the body, they are capable of destroying the tissues due to the molecular reactivity of various macromolecules in the body, which leads to the development of insulin resistance. These effects of oxidative stress can promote the evolution of complications of Diabetes mellitus. Seaweeds have proved to be an outstanding resource of nutrients and secondary metabolites. In vitro studies of the effect of Phlorotannins from Sargassum ilicifolium on the biomarkers are surveyed. The present investigation suggests that the antidiabetic activity of Sargassum ilicifolium may be due to its hypoglycemic, antioxidant, and alpha-amylase inhibiting property. Thus, this seaweed may favour diabetic individuals. Further research is required to inquire into free radicals and its relationship with diabetes, and its complications, and to make lucid the mechanisms by which a rise in oxidative stress accelerates the evolution of diabetic complications, in an effort to increase the options for treatment.
Keywords: Free radicals, oxidative stress, Diabetes mellitus, Seaweeds.
Diabetes mellitus is a progressive disorder that causes disturbances of carbohydrate, fats and protein metabolism. It is characterized by chronic hyperglycemia, where the blood sugar levels are raised, either due to a deficit in insulin secretion or action (insulin resistance). Hence, a curative approach in regard to treating diabetes is to decrease high blood sugar post a meal, which can be achieved by the inhibiting alpha-amylase and alpha-glucosidase, which are the carbohydrate-hydrolyzing enzymes. These enzymes serve as the major digestive enzymes in the digestion of carbohydrates. ?-amylase is involved in the long chain carbohydrates breakdown, where it breaks down starch and disaccharides to glucose and ?–glucosidase helps in intestinal absorption. ?–amylase and ?–glucosidase enzymes inhibitors are the potential targets for the development of the lead compounds for diabetes therapy.
Oxidative stress results from an imbalance between pro-oxidant and antioxidant homeostasis, leading to the production of toxic reactive oxygen species (ROS) such as peroxyl radicals hydroxyl and superoxides. ROS formation takes place in human cells, which attack the macromolecules like membrane lipids, proteins, and DNA, leading to many health problems such as cancer, diabetes mellitus, and age-related health deterioration condition. Antioxidants may have a positive impact on human health as they protect the human body against injury by ROS. Amongst the sources of natural antioxidants, marine seaweeds are considered to be a rich source of antioxidants.
Seaweeds are plant-like organisms that mostly exist attached to rock or any other hard substratum in coastal areas. Sargassum species are found throughout tropical and subtropical regions and are reported to produce metabolites such as terpenoids, polysaccharides, polyphenols, sargachromenol, plastoquinones, steroids, glycerides etc., which possess several remedial activities. It has been considered as a therapeutic food of this century, as it possesses many pharmacological properties. Also, research is being carried out on it to reveal its other pharmacological properties.
Brown algae such as kelps and rockweeds or Sagassacean species and a few red algae contain phlorotannins, a type of tannins, proved for showing anti-diabetic, anti-cancer, anti-oxidative, antibacterial, radioprotective and anti-HIV properties. As they are called tannins, they have the ability to precipitate proteins. It has been observed that some phlorotannins have the ability to oxidize and form covalent bonds with some proteins.