Bioactivity of cottonseed-derived materials for nutrition and health

Authors: Cao, Heping

Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 3/1/2023
Publication Date: 5/31/2023
Citation: Cao H., and Sethumadhavan K., 2023. Bioactivity of cottonseed-derived materials for nutrition and health. In: Proceedings of Beltwide Cotton Conferences, January 10-12, 2023, New Orleans, Louisiana. p. 35-46.

Interpretive Summary: Cottonseed is classified as either glanded or glandless depending on the presence or absence of pigment glands which contain toxic gossypol. Cottonseed is composed of approximately 10% linters, 40% hulls and 50% kernels. The kernels contain about 35% oil and 40% protein. The presence of gossypol in glanded seed limits its use primarily to feed ruminants. Glandless seed does not contain gossypol glands and has only trace levels of gossypol which may be useful as a food ingredient or as a feed for non-ruminant animals. The objective of this study was to develop acidic juices and drinks fortified with glandless cottonseed protein. Protein isolate was purified from glandless cottonseed by NaOH solubilization and HCl neutralization. Protein isolate was added to 4 types of beverages: 1) apple juice (fruit juice), 2) grape juice (formulated fruit drink), 3) orange juice (pulpy fruit juice), and 4) Pepsi soda (soda product). Soluble protein was determined after incubation and mixing overnight at 37°C and room temperature. The results showed that only about 10% of the protein was recovered in the soluble phase, indicating low solubility of cottonseed protein in the beverages. Therefore, cottonseed protein solubility was investigated further under different temperatures, buffer pH, and detergent. The proteins were evaluated with several protein assays as well as gel electrophoresis. The results provided useful information for increasing the solubility of glandless cottonseed protein for developing acidic juices and drinks.

Technical Abstract: Plant polyphenols have been used for the prevention and treatment of various diseases since ancient history. Cottonseed contains many bioactive compounds including polyphenols. Therefore, cottonseed value might be increased by providing bioactive polyphenols for improving nutrition and health. The specific objectives of this study were to isolate bioactive polyphenolic extracts free of gossypol from cottonseed, to study the effect of cottonseed extracts on cell viability of mammalian cells, and to study the effect of cottonseed extracts on gene expression in mammalian cells. Glanded and glandless cottonseed was used in the study. Cottonseed coat and kernel was ground and sequentially extracted with chloroform, hexane and ethanol. Ethanol extracts were evaluated by mass spectrometry to be essentially free of gossypol (<1 ppm, FDA guideline: 450 ppm). Cottonseed extracts were used to treat mammalian cells, along with plant toxin gossypol and bacterial toxin lipopolysaccharide (LPS). Cottonseed extracts and LPS had minor effects on cell viability, but gossypol had strong inhibitory effects on cancer and immunological cells. Expression of genes was analyzed by quantitative PCR for important biomarkers involved in insulin signaling pathway (IR, PIK3R1, PKB/AKT1, GSK3b), glucose transport (GLUT), lipid biosynthesis (DGAT), and inflammatory responses (TTP, HuR, TNF, COX, GM-CSF, INFr, IL, VEGF). The results showed that cottonseed extracts had small effects, but gossypol and LPS had strong effects on gene expression. Kernel extract significantly reduced mRNA levels of many proinflammatory cytokine genes, suggesting potential effects of cottonseed kernel extracts on reducing inflammation. These results suggest that cottonseed value may be increased by providing bioactive ethanol extract to be used for improving nutrition and preventing inflammatory diseases.