a particular kind or species of matter with uniform properties

(biology) any agency bringing about activation; a molecule that increases the activity of an enzyme or a protein that increases the production of a gene product in DNA transcription

prohibit, forbid, or prevent from doing something

limit, block, or decrease the action or function of

an agent that retards or restrains the action of angiotensin II

substance that inhibits oxidation or inhibits reactions promoted by oxygen or peroxides

(chemistry) a substance that retards a chemical reaction or diminishes the activity of a catalyst

any substance used to slow down neutrons in nuclear reactors

a fragrant organic chemical compound in the benzopyrone chemical class; it is a natural substance found in many plants.