Russian Food Direct offer 50 gram cartons of rowan berries (presumably dried) mainly, it seems, for their health giving properties.
On their web site it says of this species:
Its fruit contains carotene, ascorbic acid (up to 92 mg%), vitamin E, essential oil, malic, citric acid, bitter and tannins, sugars, pigments, alcohol sorbitol, antibacterial substances.
Sorbus fruits are very rich in vitamin C and other vitamins and important substances. Sorbus fruits are used as polyvitaminic substance. The ripe berries furnish an acidulous and astringent gargle for sore throats and inflamed tonsils. For their anti-scorbutic properties, they have been used in scurvy. The astringent infusion is used as a remedy in haemorrhoids and strangury. In herbal medicine, a decoction of the bark is given for diarrhoea and used as a vaginal injection in leucorrhoea.
I am surprised they are not better known for these medicinal purposes.