Phytosterol Composition of Hybrid Hibiscus Seed Oils

The seed oils from fifteen hybrid Hibiscus varieties were analyzed for desmethyl sterol content to identify bioactive compounds that could promote the use of these oils for edible applications. Hibiscus is being developed as a new crop with edible and nutraceutical applications for the component tissues and tissue extracts. Previously, hybrid varieties were developed for ornamental purposes on the basis of flower morphology and color. Currently, the effects of selective breeding on seed oil components are of interest as these represent potential natural products with bioactive properties. In the present study, sterol structures were identified as the corresponding trimethyl silyl ether derivatives obtained from the unsaponifiable fraction of the seed oils. This material contained an average of 32 wt % sterols and exhibited a relative composition of sitosterol, 76.3%; campesterol, 10.3%; stigmasterol, 7.3%; 5-avenasterol, 4.4%; and cholesterol, 0.6%. The content of 5-avenasterol showed statistically significant variation among the hybrid varieties with a range of 1.2−5.8%. Keywords: Hibiscus; sitosterol; stigmasterol; campesterol; avenasterol; seed oil