Vicilin and legumin storage proteins are abundant in water and alkali soluble protein fractions of glandless cottonseed

In this work, we sequentially extracted water (CSPw)- and alkali (CSPa)-soluble protein fractions from glandless cottonseed. SDS-Gel electrophoresis separated CSPw and CSPa to 8 and 14 dominant polypeptide bands (110–10 kDa), respectively. Liquid chromatography-electrospray ionization-tandem mass spectrometry identified peptide fragments from 336 proteins. While the majority of peptides were identified as belonging to vicilin and legumin storage proteins, peptides from other functional and uncharacterized proteins were also detected. Based on the types (unique peptide count) and relative abundance (normalized total ion current) of the polypeptides detected by mass spectrometry, we found lower levels (abundance) and types of legumin isoforms, but higher levels and more fragments of vicilin-like antimicrobial peptides in glandless samples, compared to glanded samples. Differences in peptide fragment patterns of 2S albumin and oleosin were also observed between glandless and glanded protein samples. These differences might be due to the higher extraction recovery of proteins from glandless cottonseed as proteins from glanded cottonseed tend to be associated with gossypol, reducing extraction efficiency. This work enriches the fundamental knowledge of glandless cottonseed protein composition. For practical considerations, this peptide information will be helpful to allow better understanding of the functional and physicochemical properties of glandless cottonseed protein, and improving the potential for food or feed applications.

Cottonseed Ethanol Extracts and Gossypol Regulate Anti-Inflammatory Tristetraprolin Family Gene Expression in Mouse Cells

Objectives Bioactive plant extracts have been used for the prevention and treatment of various diseases. One of the major classes of bioactive compounds is plant polyphenols. The objective of this study was to investigate the effect of cottonseed ethanol extracts and gossypol on the cytotoxicity and regulation of anti-inflammatory tristrataprolin (TTP) family gene expression in mouse cells. Methods Mouse RAW 264.7 macrophages and 3T3-L1 adipocytes were treated with various concentrations of cottonseed extracts, gossypol and lipopolysaccharides (LPS, as a control) for 2, 8, 24 and 72 h. MTT, qPCR and immunoblotting assays were used to evaluate the effects of cottonseed extracts, gossypol and LPS on cell viability and gene expression in the mouse cells. Results No cytotoxicity effect was observed in macrophages treated with extracts from the coat or kernel of glanded and glandless cottonseed. Similarly, the viability of mouse adipocytes was not affected by cottonseed extracts. In contrast, gossypol and LPS were toxic to macrophages but not adipocytes under high concentration or long time treatment. Cottonseed extracts exhibited modest effect on TTP family gene expression in macrophages but glandless cottonseed coat extract significantly increased TTP mRNA and protein levels with a magnitude similar to cinnamon and green tea polyphenol extract and insulin. Conclusions These results demonstrated that cottonseed extracts are harmless towards the mouse cells and that glandless cottonseed coat extract stimulates TTP gene expression. We propose that glandless cottonseed is a safe source of plant polyphenols with anti-inflammatory property. Funding Sources This work was supported by the USDA-ARS Quality and Utilization of Agricultural Products National Program 306 through CRIS 6054-41,000-103-00-D. USDA is an equal opportunity provider and employer.