Seaweeds are a predominant component of marine flora. There are several species of seaweed or macroalgae: red, brown and green. Seaweeds are a rich source of many bioactive secondary metabolites with extraordinary medicinal properties, ripe for industrial exploitation.
Recently, Kajal Chakraborty and team from the Central Marine Fisheries Research Institute, Cochin discovered sulphated polysaccharide in brown seaweed, Sargassumwightii. Sulphated polysaccharides are known to have pharmacological potential.
The team has been collecting samples of seaweeds, to extract biochemical compounds and to analyse them using techniques and instruments such as ion exchange chromatography, high-pressure liquid chromatography, and NMR spectroscopic analysis. Then they evaluate the chemical compounds for pharmacological properties with reference to antioxidant, anti-inflammatory, antidiabetic, and antihypertensive activities using different in vitro models.
Now, from the brown Sargassumwightii, the scientists extracted a polysaccharide, polygalactopyranosyl-fucopyranan, which, they report, has higher anti-inflammatory selectivity towards the inducive pro-inflammatory enzyme, cyclooxygenase-2. Most anti-inflammatory drugs inhibit both cyclooxygenase-1 and cyclooxygenase-2. But inhibiting cyclooxygenase-1 leads to side effects. So the sulphated carbohydrate from seaweed may be useful for treating inflammation, with less side effects.
The polysaccharide, the scientists found, is more selective than the synthetic non-steroidal anti-inflammatory drug, aspirin. The extract also showed potent lipoxygenase-5 inhibition – the typical action of antidiabetic drugs. The antidiabetic property was comparable to that of the antidiabetic agent, acarbose, and diprotein-A, they say.
The scientists found that the sulphated carbohydrate displayed potential antihypertensive activity also, as evidenced by the inhibition of the angiotensin-converting enzyme-I, the mode of action of antihypertensive drugs.
The team from the ICAR-CMFRI proposes that the sulphated polygalactopyranosyl-fucopyranan could be a potential lead in the fight against inflammation, type 2 diabetes and hypertension, besides its use as a natural antioxidant.
However, further studies need to be be conducted before the brown macroalga, Sargassumwightii, becomes raw material for the pharmaceutical industry.
In the meantime, if people in Kerala are as willing to include seaweeds in food as the Koreans and the Japanese, perhaps some lifestyle diseases will disappear from the list of public health problems.
Appl. Phycol., 30: 1971–1988 (2018)
Sileesh Mullasseri, Kerala University of Fisheries and Ocean Studies