Oxidized phytosterols increase by ageing in photoautotrophic cell cultures of Chenopodium rubrum

Abstract

Young and old cell cultures of Chenopodium rubrum were investigated for their content of phytosterol derivatives by gas chromatography-mass spectrometry. The ratio of the main phytosterol constituents, sitosterol, stigmasterol and campesterol (1.2:2.4:1.0) remained approximately constant, but their overall content (402.5 μg g −1 dry wt) decreased from 11 days to 8 weeks old cell cultures by about 64% (260.1 μg g −1 dry wt); in constrast the content of corresponding epoxides increased from traces at day 11 to 11.1 μg g −1 (dry wt) at the 8th week. A comparable increase was observed for 3,5,6-trihydroxysteranes (2.8 μg g −1 dry wt), day 11; 27.5 μg g −1 dry wt), 8 weeks). The content of sterols oxidized in position C-7 showed also an increase from 1.9 μg g −1 dry wt) (11 days) to 51.7 μg g −1 dry wt) (8 weeks). These results show that the increase of phytosterol oxidation products correlated with age of the cell culture. Therefore, the sterol epoxide content and related oxidation products may be used as a measure for ageing.