Arctostaphylos uva-ursi
The plant contains diverse phytochemicals, including ursolic acid, tannic acid, gallic acid, some essential oils and resin, hydroquinones (mainly arbutin, up to 17%), tannins (up to 15%), phenolic glycosides and flavonoids. "Arctostaphylos uva-ursi" leaves contain arbutin, which metabolizes to form hydroquinone, a potential liver toxin.