Phytosterols in the seeds of wild sunflower species

Abstract

Ingestion of phytosterols prevents intestinal absorption of cholesterol in humans and results in a lowering of serum cholesterol, which has stimulated the use of phytosterols as enriched food ingredients in functional foods. Sunflower seeds and oils are rich sources of phytosterols. The variation reported for these compounds in cultivated sunflower germplasm is low. As for many other traits, wild sunflower species may contain valuable unexplored variation for phytosterol content and profile. The objective of this research was to evaluate variation for seed phytosterols in a set of 47 wild Helianthus species from the USDA-ARS collection. An impressive variation was identified for total phytosterol content (1017 to 4308 mg kg-1 seed) and proportion of individual phytosterols, particularly campesterol (5.1 to 16.3%) stigmasterol (3.1 to 23.9%), beta-sitosterol (35.1 to 72.3%), delta-5-avenasterol (1.9 to 20.5%), delta-7-stigmastenol (1.1 to 20.3%), and delta-7-avenasterol (0.3 to 10.6%). Some of the extremes of these ranges of variation have not been identified in cultivated sunflower. The feasibility of transferring genes determining interesting phytosterol traits to cultivated sunflower should be investigated.