Seaweeds: A Comprehensive Review of Pharmacological Interests

The global economic impact of the five leading chronic diseases - cancer, diabetes, mental illness, CVD, and respiratory disease - could reach $47 trillion over the next 20 years, according to a study by the World Economic Forum (WEF). According to the WHO, 80% of the world's population primarily those of developing countries rely on plant-derived medicines for the healthcare. The purported efficacies of seaweed derived phytochemicals showing great potential in obesity, T2DM, metabolic syndrome, CVD, IBD, sexual dysfunction and some cancers. Therefore, WHO, UN-FAO, UNICEF and governments have shown a growing interest in these unconventional food with health-promoting effects. Edible marine macro-algae (seaweed) are of interest because of their value in nutrition and medicine. Seaweeds contain several bioactive substances like polysaccharides, proteins, lipids, polyphenols, and pigments, all of which may have beneficial health properties. People consume seaweed as food in various forms: raw as salad and vegetable, pickle with sauce or with vinegar, relish or sweetened jellies and also cooked for vegetable soup. By cultivating seaweed, coastal people are getting an alternative livelihood as well as advancing their lives. In 2005, world seaweed production was totaled 14.7 million tons which more than double (30.4 million tons) in 2015. The present market value is nearly $6.5 billion and projected to reach some $9 billion seaweed global market by 2024. Aquaculture is recognized as the most sustainable means of seaweed production and accounts for approximately 27.3 million tons (more than 90%) of global seaweed production per annum. Asian countries produced 80% for world markets where China alone produces half of the total demand. The top six seaweed producing countries are China, Indonesia, Philippines, Korea, and Japan.Seaweeds are well-known for their exceptional capacity to accumulate essential minerals and trace elements needed for human nutrition, although their levels are commonly very variable depending on their morphological features, environmental conditions, and geographic location. Food security, legislative measures to ensure monitoring and labeling of food products are needed. Being subject to environmental influences from its habitat, seaweeds also entail water-borne health risks such as organic pollutants, toxins, parasites, and heavy metals. Having in mind the serious environmental problems raised in coastal areas by urbanization and industrialization, the concentration of toxic elements in edible macroalgae is now a growing concern, mainly considering their increment in Western diet. Although many studies demonstrated their therapeutic value in various ailments but most of them performed on experimental animals. Proper labeling is necessary along with instruction of content, source and use. Furthermore, controlled human intervention studies with health-related end points to elucidate therapeutic efficacy are required