Development and Validation of Quantitative H-1 NMR Spectroscopy for the Determination of Total Phytosterols in the Marine Seaweed Sargassum

摘要

Knowledge of phytosterol (PS) contents in marine algae is currently lacking compared to those in terrestrial plants. The present studies developed a quantitative H-1 NMR method for the determination of the total PSs in Sargassum. The characteristic proton signal H-3 alpha in PSs was used for quantification, and 2,3,4,5-tetrachloro-nitrobenzene was used as an internal standard. Seaweed samples could be recorded directly after total lipid extraction and saponification. The results showed that the PS contents in Sargassum fusiforme (788.89-2878.67 mg/kg) were significantly higher than those in Sargassum pallidum (585.33-1596.00 mg/kg). The variable contents in both species suggested that fixed raw materials are very important for future research and development. Orthogonal projection to latent structures discriminant analysis was carried out in the spectral region of delta 3.00-6.50 in the H-1 NMR spectrum. S. fusiforme and S. pallidum could be separated well, and the key sterol marker was fucosterol.