Screening of Tocopherol and Tocotrienol Diversity in Cornus Species Seeds Using a Sustainable Extraction Protocol

Although not major crops, Cornaceae species, the dogwood family, are common in most continents and used primarily as ornamental crops, though some are used for food as well. In the present study, tocochromanol-tocopherol (T) and tocotrienol (T3)-contents were analyzed in the seeds of twenty-four Cornus species belonging to six Cornus subgenera. Given the substantial number of samples included in this study, we applied a fast extraction protocol using an ethanol and ultrasound treatment and systematically compared its performance with that of a conventional alkaline saponification method. Total tocochromanol content ranged from 0.78 to 21.63 mg 100 g^-1 dry weight (dw) seeds in C. kousa and C. controversa, respectively. The highest mean total tocochromanol content was (16.70 ± 5.28 mg 100 g^-1 dw), followed by C. nuttallii (12.96 mg 100 g^-1 dw) and C. sanguinea (9.10 ± 2.47 mg 100 g^-1 dw). The major tocochromanols in the seeds were γ-T3 (up to 93% in C. rugosa), α-T (up to 98% in C. mas) and γ-T (up to 60% in C. controversa). Tocochromanol composition was strongly subgenus-dependent. The applied sustainable solvent-ethanol and ultrasound-treatment approach for the extraction of tocochromanols demonstrated the suitability of this method for screening daily Cornus species seed samples and potential extraction.