a substance that retards or stops an activity

any compound of carbon and another element or a radical

a coumarin found in the root of plants in the genus Scopolia, in chicory, in Artemisia scoparia, in the roots and leaves of Stinging Nettle (Urtica dioica ), in the passion flower, in Brunfelsia, in Viburnum prunifolium or Kleinhovia hospita.

an anticoagulant that functions as a vitamin K antagonist (like warfarin).