Samuthirapandian Ravichandran, Faculty of Marine Sciences, Annamalai University has been searching for pharmacologically useful biochemicals from marine organisms. Many potential antibiotics and anticancer compounds have been discovered in marine organisms in the recent years.
Now Ravichandran has turned his attention to sphingolipids in the marine crab, Dromia dehaani. Sphingolipids are a class of lipids which play a key role in the proper functioning of cells. They have been found to be useful against intestinal and cervical cancer. Ravichandran talked to Supriya Tilvi and S Prabha Devi at the CSIR-NIO, Goa. They too were interested.
They collected samples of the crab from fishers, cultured them in sea water and provided adequate food for two weeks. Then they cut the walking legs of the crabs and collected the hemolymph – analogous to a combination of blood and immune system in such animals. The researchers separated the cells from the hemolymph fluid using a centrifuge. The fluid from the hemolymph without the cells was used for testing anticancer activity.
To test, the team first induced cancer in male Wistar rats by adding small amounts of nitrosodimethylamine in their drinking water. In fifteen weeks these animals start losing weight. But in the experimental animals that received oral doses of hemolymph there was no loss of weight.
The researchers checked the liver of experimental and control rats. The liver of the control rats that did not get oral doses of hemolymph had gained weight while, in the experimental rats, the liver appeared normal.
While all six rats that received only nitrosodimethylamine developed cancerous nodules, only two out of the six that received the hemolymph along with nitrosodimethylamine showed such nodules, says S Ravichandran Annamalai University.
Even in these cases, the number of nodules was lower, adds Elangovan RethnaPriya, his colleague.
The team characterised the sphingolipids in the hemolymph using different spectroscopic techniques. In the active fraction, they found a sphingolipid similar to one that was earlier identified in cyanobacteria. The sphingolipid has been shown to be a platelet activator earlier – which provides clues about a probable mechanism of anti-cancer activity.
Sphingolipids from biological sources are assumed to be safe and recent evidence suggests the usefulness of sphingolipids as adjuvant in cancer therapy. However, clinical trials need to be undertaken before this sphingolipid can be used in clinical practice.
Chemistry and Physics of Lipids, 221: 73-82 (2019);
Central University of Kerala
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