alkaloid
noun
al·ka·loid
ˈal-kə-ˌlȯid 
: any of numerous usually colorless, complex, and bitter organic bases (such as morphine or caffeine) containing nitrogen and usually oxygen that occur especially in seed plants and are typically physiologically active
Examples of alkaloid in a Sentence
Recent Examples on the Web
The most abundant of the psychoactive alkaloids in kratom are mitragynine and speciociliatine, Smith said.
—
Kristen Rogers, CNN Money, 26 Aug. 2025
These two small molecules are alkaloids that activate receptors in the brain to trigger the main psychoactive effects of magic mushrooms.
—Joshua Kellogg, The Conversation, 15 Aug. 2025
Researchers suspect the environment may be responsible for the plants’ unexpected return to ancestral alkaloids.
—Sarah Kuta, Smithsonian Magazine, 9 July 2025
Too many alkaloids, though, can make the plant toxic to humans.
—New Atlas, 29 June 2025
See All Example Sentences for alkaloid
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Kristen Rogers, CNN Money, 26 Aug. 2025
These two small molecules are alkaloids that activate receptors in the brain to trigger the main psychoactive effects of magic mushrooms.
—Joshua Kellogg, The Conversation, 15 Aug. 2025
Researchers suspect the environment may be responsible for the plants’ unexpected return to ancestral alkaloids.
—Sarah Kuta, Smithsonian Magazine, 9 July 2025
Too many alkaloids, though, can make the plant toxic to humans.
—New Atlas, 29 June 2025
See All Example Sentences for alkaloid
Cite this Entry
“Alkaloid.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/alkaloid. Accessed 9 Sep. 2025.
Copy CitationMedical Definition
alkaloid
noun
al·ka·loid
ˈal-kə-ˌlȯid
: any of numerous usually colorless, complex, and bitter organic bases (as morphine or caffeine) containing nitrogen and usually oxygen that occur especially in seed plants and are typically physiologically active
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