The drug contains 2–3% mucilages (arabinogalactans and xyloglucans), 0.1–0.7% phenylethanoid glycosides (verbascoside), 0.1–0.5% iridoid glycosides (aucubin, catalpol), phenolic acids (caffeic, ferulic, rosmarinic), flavonoids (glycosides of 6-hydroxyluteolin, luteolin, apigenin, tamarixetin), and triterpene saponins (thapsuin, verbascosaponin).
Used for the relief of symptoms in sore throats associated with dry cough and colds.
It is the dried corolla of the flower. For V. densiflorum: the corolla is about 30 mm, nearly flat, deeply divided into five rounded lobes; V. thapsus: corolla about 20 mm, pale yellow or brown, wheel-shaped, with five outspread lobes, hairy on the outside and glabrous inside with light brown veins, five stamens alternate with corolla lobes (2 stamens longer than the others), the anthers positioned transversely; V. phlomoides: corolla about 30 mm, pale yellow or orange, anthers convergent.
The drug is listed in the pharmacopoeia.
In pulverized drug under the microscope we can see:
Multicellular covering trichomes
Star-shaped endothecium
Club-shaped covering trichomes of the anther with a granular surface
