Anthocyanins in wild relatives of strawberry (Fragaria L.)

Fruit chemistry of wild relatives of strawberries (Fragaria L.) at the USDA National Clonal Germplasm Repository (NCGR) in Corvallis, Oregon, has not been well documented. The objective of this study was to examine profiles and total anthocyanin content of 9 strawberry species, 8 subspecies, and one outgroup, Potentilla indica (Andrews) Th. Wolf. Anthocyanin profiles were performed using high-performance liquid chromatography (HPLC). The total anthocyanins were expressed as mg of anthocyanin 100 g-1 of fresh wt. The germplasm evaluated included recently collected F. cascadensis K.E. Hummer from the Oregon High Cascade Mountains, along with octoploid beach strawberries (F. chiloensis (L.) Mill.) from Oregon, Hawaii, California, and Chile; 3 subspecies of F. virginiana Mill. from across the United States; 4 cultivated examples of octoploid F. × ananassa; the hexaploid, F. moschata Duchesne from Switzerland; and the diploids F. vesca L. from California and Nova Scotia, F. nipponica Makino from Japan, F. viridis Duchesne from Europe, and F. nilgerrensis Schltdl. ex J. Gay from China and Vietnam. The samples examined had varying amounts of typical strawberry anthocyanins, cyanadin-3-glucoside (Cy 3-gluc), pelargonidin-3-glucoside (Pg 3-gluc), and pelargonidin-3-rutinoside (Pg 3-rut). In addition, atypical anthocyanin peaks were observed in some samples, particularly Potentilla. Total anthocyanins ranged from 49.27 mg 100 g-1 fresh wt (red-fruited F. moschata L. with Cy 3-gluc as the primary peak) to about 1 mg 100 g-1 fresh wt or less for white-fruited types. Potentilla indica fruit had 89-95% atypical anthocyanins, though Cy 3-gluc, Pg-3-gluc and Pg 3-rut were present in reduced quantities. The total anthocyanin concentration of red-fruited F. cascadensis included Pg 3-gluc > Cy 3-gluc, without Pg 3-rut, though with only 2 to 6% atypical anthocyanins. White-fruited types contained the three compounds, though in different ratios than red-fruited cultivars. Fragaria nilgerrensis had white fruit with trace amounts of Cy 3-gluc > Pg 3-gluc > Pg 3-rut. While reports have been published determining anthocyanin concentration of cultivated hybrid strawberries for food processing, further work is needed to examine anthocyanin profiles for diverse
strawberry species.

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