Phytosterols (plant sterols/stanols), are naturally occurring compounds in plant cells, which play important roles in plants membrane stability and metabolism [1]. These phytochemicals are members of the triterpene family and are structurally similar to cholesterol. More than 250 phytosterols have been reported but the more important are β-sitosterol, campesterol and stigmasterol, which represent 98% of phytosterols in plants and human diet [2]. Various studies reported that phytosterols possess several health benefits such as anti-cancer, anti-inflammatory, and anti-oxidation activities. However, phytosterols have generated a worldwide interest due to their blood LDL-cholesterol lowering effects. This effect recognized and regulated by European and US guidelines, stimulated the development of functional foods enriched in phytosterols such as dairy products [3]. The supplementation of dairy products requires many studies: analysis of food composition; analysis of functional ingredient; stability studied of phytosterols during food processing and storage. The quantification of phytosterols is therefore fundamental for supplementation studies. The analysis of phytosterols is usually performed by gas chromatography coupled to flame ionization detection (GC-FID) or mass spectrometry (GC–MS). Recently, modern methods based on liquid chromatography have been developed. However, the absence of chromophore and the low ionization of phytosterols limit their detection through diode array detector (DAD) and electrospray ionization (ESI-MS) [4]. Therefore, a pre-column derivatization step was necessary to improve the HPLC analysis of phytosterols. For this purpose, dansyl chloride (4 mg mL−1) was used as derivatizing agent and different reaction parameters have been optimized: catalysts (DMAP, Na2CO3, NaHCO3 and (C2H5)3N ), concentrations (1, 2, 3, 6, 8 and 10 µg mL−1), solvent (methanol, acetone, acetonitrile, hexane, ethyl acetate and dichloromethane), time (10, 20, 30 and 60 min) and temperatures (30, 40 and 60 °C) of derivatization. The highest yields of derivatization were obtained using DMAP as catalyst, CH2Cl2 as solvent at 40 °C for 30 min. The precolumn-derivatization improves the UV detection and allowed the analysis of phytosterols by ESI-MS. Moreover, the derivatization enhances the chromatographic separation of phytosterols. References [1] Moreau, R. A., Nyström, L., Whitaker, B. D., Winkler-Moser, J. K., Baer, D. J., Gebauer, S. K., & Hicks, K. B. Prog Lipid Res, 2018, 70, 35-61. [2] Nzekoue, F.K, Khamitova, G., Angeloni, S., Sempere, A.N., Tao, J., Maggi, F., Xiao, J., Sagratini, G., Vittori, S. and Caprioli, G., 2020. Food Chem, 2020, p.126836. [3] Commission Regulation (EU) No 686/2014 of 20 June 2014. OJEU, 2014, 182, 1. [4] Nzekoue, F. K., Caprioli, G., Ricciutelli, M., Cortese, M., Alesi, A., Vittori, S., & Sagratini, G. Food Res Int, 2020, 131, 108998.
Phytosterols: structural diversity, health benefits, supplementation, analytical methods and challenges.
Franks Kamgang Nzekoue;Giovanni Caprioli;Sauro Vittori;Gianni Sagratini.
2020-01-01
Abstract
Phytosterols (plant sterols/stanols), are naturally occurring compounds in plant cells, which play important roles in plants membrane stability and metabolism [1]. These phytochemicals are members of the triterpene family and are structurally similar to cholesterol. More than 250 phytosterols have been reported but the more important are β-sitosterol, campesterol and stigmasterol, which represent 98% of phytosterols in plants and human diet [2]. Various studies reported that phytosterols possess several health benefits such as anti-cancer, anti-inflammatory, and anti-oxidation activities. However, phytosterols have generated a worldwide interest due to their blood LDL-cholesterol lowering effects. This effect recognized and regulated by European and US guidelines, stimulated the development of functional foods enriched in phytosterols such as dairy products [3]. The supplementation of dairy products requires many studies: analysis of food composition; analysis of functional ingredient; stability studied of phytosterols during food processing and storage. The quantification of phytosterols is therefore fundamental for supplementation studies. The analysis of phytosterols is usually performed by gas chromatography coupled to flame ionization detection (GC-FID) or mass spectrometry (GC–MS). Recently, modern methods based on liquid chromatography have been developed. However, the absence of chromophore and the low ionization of phytosterols limit their detection through diode array detector (DAD) and electrospray ionization (ESI-MS) [4]. Therefore, a pre-column derivatization step was necessary to improve the HPLC analysis of phytosterols. For this purpose, dansyl chloride (4 mg mL−1) was used as derivatizing agent and different reaction parameters have been optimized: catalysts (DMAP, Na2CO3, NaHCO3 and (C2H5)3N ), concentrations (1, 2, 3, 6, 8 and 10 µg mL−1), solvent (methanol, acetone, acetonitrile, hexane, ethyl acetate and dichloromethane), time (10, 20, 30 and 60 min) and temperatures (30, 40 and 60 °C) of derivatization. The highest yields of derivatization were obtained using DMAP as catalyst, CH2Cl2 as solvent at 40 °C for 30 min. The precolumn-derivatization improves the UV detection and allowed the analysis of phytosterols by ESI-MS. Moreover, the derivatization enhances the chromatographic separation of phytosterols. References [1] Moreau, R. A., Nyström, L., Whitaker, B. D., Winkler-Moser, J. K., Baer, D. J., Gebauer, S. K., & Hicks, K. B. Prog Lipid Res, 2018, 70, 35-61. [2] Nzekoue, F.K, Khamitova, G., Angeloni, S., Sempere, A.N., Tao, J., Maggi, F., Xiao, J., Sagratini, G., Vittori, S. and Caprioli, G., 2020. Food Chem, 2020, p.126836. [3] Commission Regulation (EU) No 686/2014 of 20 June 2014. OJEU, 2014, 182, 1. [4] Nzekoue, F. K., Caprioli, G., Ricciutelli, M., Cortese, M., Alesi, A., Vittori, S., & Sagratini, G. Food Res Int, 2020, 131, 108998.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
