Compositional and Functional Analysis of Golden and Brown Flaxseed: Nutrients, Bioactive Phytochemicals, Antioxidant Activity, and Cellular Responses.

BACKGROUND: Flaxseed (Linum usitatissimum L.) represents a unique source of bioactive compounds with demonstrated health benefits. The main aim of the research was to investigate the chemical composition, content of bioactive compounds and biological activities of various types of flaxseed and their defatted forms. METHODS: Proximate composition (crude fat, protein, ash, digestible carbohydrates, fiber) was determined, and fatty acid profiles were analyzed via GC-MS (gas chromatography-mass spectrometry). Mineral content was measured by atomic absorption spectrometry, while total and individual polyphenols were quantified spectrophotometrically and by HPLC (high-performance liquid chromatography). Antioxidant activity was assessed using three assays. In vitro functional assays evaluated the effects of flaxseed extracts on lactic acid bacteria adhesion in two cellular models, nitric oxide production in liposaccharide (LPS)-stimulated RAW 264.7 macrophages, proliferation and apoptosis of MCF-7 breast cancer cells. RESULTS: Significant differences (p ≤ 0.05) were observed in the proximate composition: brown flaxseed exhibited the highest crude fat content, whereas defatted seeds had higher levels of digestible carbohydrates and ash. α-Linolenic acid was the dominant fatty acid, with the highest concentration in defatted golden flaxseed. Defatted forms generally displayed increased mineral concentrations, particularly calcium, magnesium, potassium, and iron. The polyphenolic content and antioxidant activity were highest in defatted brown flaxseed, which also exhibited the greatest diversity of individual polyphenols. Flaxseed extracts modulated the adhesion of lactic acid bacteria, reduced the production of nitric oxide in RAW 264.7 macrophages, inhibited the proliferation of MCF-7 breast cancer cells in a dose- and time-dependent manner, and induced apoptosis of the mentioned cells. CONCLUSIONS: Flaxseed, especially the brown type, could be a promising source of bioactive compounds with antioxidant, anti-inflammatory and anticancer potential, supporting its use in nutritional and functional applications.