Assertion: periwinkle | /r/MadeOf | tannin
Facets:
Source sentences:
text: Periwinkle also contains tannins which may help to relieve pain from canker sores or sore throats, but human studies have not been conducted to substantiate these effects 2.
text: Periwinkle contains tannins that bind up fluids and relieves inflammation.
text: Catharanthus roseus contains two classes of active compounds, the alkaloids and the tannins.