Cottonseed Bioactive Compounds and Peptides

Cotton seeds have gossypol, a green-yellow polyphenolic pigment in their glands toxic to man and monogastric animals.  Gossypol constitutes about 2.5-5.0% of the weight of dehulled cottonseed kernels.  Hence, the feeding of the seeds or their products has been limited to cattle and other ruminants.  Recently, genetically modified glandless cotton seeds were produced with negligible levels of gossypol, and adds nutritional value to non-ruminants.  Cottonseed kernels contain about 35% of oil and 40% of protein and if gossypol free, they can be found wide application in food industry.  The value of cotton seeds could be increased by finding other bioactive compounds.  In this study, we developed methods to prepare peptides, and evaluate its bioactivity in mouse macrophages.  Cotton seeds were grounded in alkaline media and defatted using organic solvents. The protein pellet was sonicated in presence of Tris buffer, pH 7.4 and the proteins were digested to peptide fragments using trypsin enzyme.  The electrophoresis of the digest showed similar pattern in both glanded and glandless cotton types.  The mouse macrophages were tested with tryptic digests for regulating cell viability and gene expression.  Cell viability assay showed that higher peptide concentrations caused some inhibition of mitochondrial activity in mouse RAW264.7 macrophages.  The effect of these peptides on immunological responses were evaluated by studying mRNA levels related to signaling pathways.  This will be a useful tool in identifying the biological nature of biopeptides and hence its usefulness in nutrition.