Tocopherol, fatty acid and phytosterol content in seeds of nine wild taxa of Sicilian Brassica (Cruciferae)

Abstract

The purpose of this study was to determine tocopherol (Toc), fatty acid and phytosterol content in dry seeds of nine wild taxa of Sicilian Brassica sect. Brassica. Analyses were performed by gas chromatography (GC)‐mass spectroscopy (MS). The biochemical analysis of dry seeds showed that in the nine taxa examined, α‐ and γ‐Toc were the major isomers, δ‐Toc was present in traces and β‐Toc was never found. All taxa had a similar fatty acid composition with C 16:0 (357.2 mg kg⁻¹ DW), C 18:1 (393.94 mg kg⁻¹ DW) and C 22:1 (618.29 mg kg⁻¹ DW) acids present in higher amount. Unsaturated fatty acids (52.5–66.5%) were more abundant than saturated (33.5–47.5%) ones relative to the total fatty acids. Moreover, sitosterol was the most abundant (61.7–69.6%) of all phytosterols in all species and subspecies, followed by brassicasterol and campesterol at 16.0–19.3% and 11.9–20.7%, respectively. Total Toc content and the relative percentage of single isoforms were useful to discriminate seeds of B. incana, B. macrocarpa, B. rupestris group and B. villosa group. On the basis of these results, B. villosa subsp. villosa, B. villosa subsp. bivoniana, B. villosa subsp. drepanensis and B. villosa subsp. tinei can be ascribed to the B. villosa group. These taxa, having the highest T‐Toc, γ‐Toc and phytosterol contents, are potentially the most bioactive ones, and could, therefore, be exploited in breeding programmes to develop genotypes with putative positive effects on human health.

Abbreviations: B, Brassica; DW, dry weight; FA, fatty acids; RH, relative humidity; T‐FA, total fatty acids; T‐Phy, total phytosterols; T‐Toc, total tocopherol; Toc, tocopherol

Keywords:

• Brassica
• Cruciferae
• fatty acids
• phytosterols
• seeds
• tocopherols

Acknowledgements

The authors thank the Germplasm Bank of the Botanical Garden of the University of Palermo for providing the accessions of Brassicaceae. Special thanks go to Prof. F. M. Raimondo for the critical review of the manuscript and to Dr Massimo Migliorini for helpful suggestions in the statistical analysis. Financial support was provided by Palermo University (Fondi di Ateneo), by the Italian MIUR (PRIN 2007) and by Siena University (P.A.R.).