Cottonseed bioactive compounds and peptides

Authors: Cao, Heping; Sethumadhavan, Kandan

Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: 3/1/2020
Publication Date: 5/15/2020
Citation: Cao, H., Sethumadhavan, K. 2020. Cottonseed bioactive compounds and peptides. Proceedings of 2020 Beltwide Cotton Conferences. p. 270-281.

Interpretive Summary: Obesity and diabetes are epidemic in the U.S. and around the world. Finding ways to slow down and prevent their occurrence would have tremendous benefits for reducing healthcare costs and improving life quality. Plant bioactive materials can potentially be used to serve these purposes. Cottonseed accounts for only 20% of the crop value due to the presence of toxic gossypol. Current work has provided useful information to increase cottonseed value by isolating bioactive extracts and compounds from cottonseed because these value-added products possess health promotion and disease prevention potential. We have developed protocols for isolating bioactive ethanol extracts with a yield of ~ 2% from cottonseed. Gossypol was shown with less than 1 ppm in cottonseed extracts, which was much less than the U.S. federal government limit of 450 ppm. Bioactive quercetin was only detected in glandless seed coat extract. No cytotoxicity effect of cottonseed extracts was observed in mouse macrophages or adipocytes. Molecular and immunoblotting assays showed that cottonseed extracts did not increase the expression of pro-inflammatory HuR expression which stabilizes cytokine mRNAs and plays an important role in tumorigenesis and inflammation. We have further demonstrated that ethanol extracts decreased breast cancer and pancreas cancer cell growth, stimulated key lipid-synthesizing DGAT2 gene expression which may be a novel target for intervention of lipid-related diseases, and increased anti-inflammatory TTP gene expression with a magnitude similar to cinnamon and green tea polyphenol extract and insulin. In particular, ethanol extract from glandless cottonseed did not have toxic gossypol but had beneficial quercetin. These results suggest that the gossypol-free ethanol extracts are safe with anti-inflammatory and anticancer properties. This information should lead a foundation for developing glandless cottonseed as a functional food for promoting human nutrition and preventing human diseases associated with inflammation such as arthritis, diabetes, obesity, cardiovascular diseases and cancers.

Technical Abstract: 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. 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. We have developed methods to prepare polyphenol compounds and peptides, and evaluate their bioactivity in mouse and human cells. The mammalian cells were tested with ethanol extracts and tryptic digests for regulating cell viability and gene expression by microscopic observation, toxic assay, protein content determination, gene expression and immunoblotting methods. Here we summarize the current research progress in cottonseed bioactive compounds and peptides. This information may help to increase cottonseed values by developing bioactive products for improving nutrition and preventing diseases.