Looking Beyond the Terrestrial: The Potential of Seaweed Derived Bioactives to Treat Non-Communicable Diseases

Abstract

Seaweeds are a large and diverse group of marine organisms that are commonly found in the maritime regions of the world. They are an excellent source of biologically active secondary metabolites and have been shown to exhibit a wide range of therapeutic properties, including anti-cancer, anti-oxidant, anti-inflammatory and anti-diabetic activities. Several Asian cultures have a strong tradition of using different varieties of seaweed extensively in cooking as well as in herbal medicines preparations. As such, seaweeds have been used to treat a wide variety of health conditions such as cancer, digestive problems, and renal disorders. Today, increasing numbers of people are adopting a "westernised lifestyle" characterised by low levels of physical exercise and excessive calorific and saturated fat intake. This has led to an increase in numbers of chronic Non-communicable diseases (NCDs) such as cancer, cardiovascular disease, and diabetes mellitus, being reported. Recently, NCDs have replaced communicable infectious diseases as the number one cause of human mortality. Current medical treatments for NCDs rely mainly on drugs that have been obtained from the terrestrial regions of the world, with the oceans and seas remaining largely an untapped reservoir for exploration. This review focuses on the potential of using seaweed derived bioactives including polysaccharides, antioxidants and fatty acids, amongst others, to treat chronic NCDs such as cancer, cardiovascular disease and diabetes mellitus.

Keywords: bioactives; cancer; cardiovascular disease; diabetes; fucoidan; non-communicable disease; prebiotics; seaweed; short-chain fatty acids.

Figure 1

Seaweeds are divided into three main groupings based largely on their pigmentation. The groupings are brown seaweeds, the red seaweeds and the green seaweeds.

Figure 2

According to the World Health Organization (WHO) (a) cardiovascular diseases, cancers, respiratory diseases and diabetes account for 82% of all deaths attributed to non-communicable diseases; (b) Each year, cardiovascular diseases account for 17.5 million deaths, cancers (8.2 million), respiratory diseases (4 million) and diabetes (1.5 million) [24].

Figure 2

According to the World Health Organization (WHO) (a) cardiovascular diseases, cancers, respiratory diseases and diabetes account for 82% of all deaths attributed to non-communicable diseases; (b) Each year, cardiovascular diseases account for 17.5 million deaths, cancers (8.2 million), respiratory diseases (4 million) and diabetes (1.5 million) [24].

Figure 3

Model for the average structure of fucoidan from Fucus vesiculosus. The core region of the fucan is composed primarily of a polymer of α (1-3) linked fucose with sulphate groups substituted at the 4 position on some of the fucose residues [35].

Figure 4

Proposed mechanism for fucoidan bioactivity (A) Macrophage activation by fucoidans as mediated through specific membrane receptor activation namely TLR-4, CD14, CR-3 and SR which induces intracellular signaling via mitogen-activation protein kinases (MAPKs); (B) Activation of macrophages leads to the production of cytokines such as IL-12, IL-2 and IFN-γ which enhance NK cell activation that may stimulate T-cell activation [41].

Figure 5

The major modifiable risk factors for the development of a chronic non-communicable disease are (1) Alcohol intake (2) Tobacco (3) Diet (4) Physical fitness

Figure 6

Putative health benefits of the three main short chain fatty acids (SCFAs), acetic acid, propionic acid and N-butyric acid. SCFA are mainly produced by the endogenous gut microbiota through the fermentation of undigested dietary fibres from the diet.