Synthesis and search for 3β,3′β-disteryl ethers after high-temperature treatment of sterol-rich samples

•3β,3′β-disteryl ethers were prepared from the reaction of sterols with MK10 catalyst.•The GC–MS method for analysing 3β,3′β-disteryl ethers was developed and validated.•3β,3′β-disteryl ethers are formed by high-temperature treatment of sterol-rich samples. It has been proven that at increased temperature, sterols can undergo various chemical reactions e.g., oxidation, dehydrogenation, dehydration and polymerisation. The objectives of this study are to prove the existence of dimers and to quantitatively analyse the dimers (3β,3′β-disteryl ethers). Sterol-rich samples were heated at 180 °C, 200 °C and 220 °C for 1 to 5 h. Quantitative analyses of the 3β,3′β-disteryl ethers were conducted using liquid extraction, solid-phase extraction and gas chromatography coupled with mass spectrometry. Additionally, for the analyses, suitable standards were synthetized from native sterols. To identify the mechanism of 3β,3′β-disteryl ether formation at high temperatures, an attempt was made to use the proposed synthesis method. Additionally, due to the association of sterols and sterol derivatives with atherosclerosis, preliminary studies with synthetized 3β,3′β-disteryl ethers on endothelial cells were conducted.