Background The diversified and high value-added utilization of cotton by products can promote the sustainable development of modern agriculture. Differences in potential nutrients among varieties can be explained by variations in the composition and abundance of fatty acids, polyphenols, carbohydrates, amino acids, and organic acids. Therefore, the analysis of metabolite species and relationships in cottonseed is meaningful for the development of cotton byproducts. Results In this study, the metabolomes of three representative cotton cultivars of different species were compared using untargeted GC-TOF/MS analysis. A total of 263 metabolites were identified from 705 peaks, and their levels were compared across cultivars. Principal component analysis and OPLS-DA clearly distinguish these samples based on metabolites. There were significant differences in the contents of amino acids, carbohydrates, organic acids, flavonoids, and lipids in G. hirsutum TM-1 compared with G. arboreum Shixiya1 and G. barbadense Hai7124. Notably, the bioactive nutrient compound catechin obtained from the differential metabolites significantly accumulated in TM-1. Furthermore, a comprehensive analysis using catechin and oil-related traits was conducted in core collections of Gossypium hirsutum. The results revealed the reliability of the GC-TOF/MS analysis, as well as that catechin content has a negative association with myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, arachidic acid, and total fatty acids. Conclusion These findings suggest that untargeted GC-TOF/MS analysis could provide a new method for investigating the underlying plant biochemistry of nutrient variation in cottonseed, and that catechin content has a negative association with oil-related traits in cottonseed. This study may pave the way to exploit the value of cotton byproducts.

Background: The diversified and high value-added utilization of cotton by-products can promote the sustainable development of modern agriculture. Differences in potential nutrient among varieties can be explained by variations in the composition and abundance of fatty acids, polyphenols, carbohydrates, amino acids and organic acids, etc. Therefore, the analysis of metabolite species and relationships in cottonseed is meaningful for the development of cotton by-products.Results: In this study, the metabolomes of the three cotton cultivars of different species were compared using an untargeted GC-TOF/MS analysis. A total of 263 metabolites were identified from 705 peaks and their levels were compared across the cultivars. PCA and OPLS-DA of these metabolites could clearly distinguish. There were significant differences in the content of amino acids, carbohydrates, organic acids flavonoids, and lipids in G. hirsutum TM-1 compared with G. arboretum Shixiya1 and G. barbadense Hai7124. It is noteworthy that the bioactive nutrient compound catechin obtained from the differential metabolites is significantly accumulated in TM-1. Furthermore, a comprehensive analysis using catechin and oil-related traits was conducted in core collections of Gossypium. And the results revealed the feasibility of the GC-TOF/MS analysis, as well as that catechin content has a negative association with myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, arachidic acid and total fatty acids.Conclusion: These fndings suggest that catechin content has a negative association with most fatty acids in cottonseed, which may provides a new solution into the underlying plant biochemistry of nutrient variation in cottonseed and pave the way to exploit the value of cotton by-products.

BACKGROUNDWaste cotton flowers, as a by‐product of cotton cultivation, are enriched with bioactive substances that render them a promising natural source of health‐promoting benefits. In this study, ultrasound‐assisted extraction (UAE), subcritical water extraction (SWE), and conventional extraction (CE) approaches were applied to extract bioactive compounds from waste cotton flowers, and the metabolic profiles, bioactive components, antioxidants, and α‐amylase inhibition of different extractions were systematically analyzed and compared.RESULTSIt was observed that UAE and CE extracts had similar metabolic profiles compared with SWE. The flavonoids and amino acids and derivatives were more prone to be extracted by UAE and CE, whereas phenolic acids tended to accumulate in SWE extract. The UAE extract had the highest amounts of total polyphenols (214.07 mg gallic acid equivalents per gram dry weight) and flavonoids (33.23 mg rutin equivalents per gram dry weight) as well as the strongest inhibition on oxidation (IC50 = 10.80 μg mL−1) and α‐amylase activity (IC50 = 0.62 mg mL−1), indicating that chemical composition was closely related to biological activity. Additionally, microstructures and thermal behaviors of the extracts were investigated and highlighted the ability of UAE.CONCLUSIONOverall, it can be concluded that UAE is an efficient, green, and economical extraction method to produce bioactive compounds from cotton flowers, and the UAE extracts could be used in food and medicine industries because of their high antioxidant and α‐amylase inhibitory activity. This study provides a scientific basis for the development and comprehensive utilization of cotton by‐products. © 2023 Society of Chemical Industry.