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

alkaloidal

ˌal-kə-ˈlȯi-dᵊl 

adjective

Examples of alkaloid in a Sentence

Recent Examples on the Web

Another drug listed in the report, mitragynine is a naturally occurring indole alkaloid found in the leaves of a psychoactive medicinal plant native to Southeast Asia, according to the National Institutes of Health. —Katie Nixon, The Tennessean, 15 May 2024

Berberine is a naturally occurring alkaloid found in various plants. —New Atlas, 3 Mar. 2025

Black Pepper Black pepper includes piperine, an alkaloid that acts as an antioxidant and may have potential fat-reducing effects. —Anna Giorgi, Verywell Health, 6 Feb. 2025

Tomatoes contain alkaloids like solanine, which may trigger an inflammatory response in some individuals. —Chelsea Rae Bourgeois, Rdn, Health, 3 Feb. 2025

Word History

First Known Use

1820, in the meaning defined above

Rhymes for alkaloid

• adenoid
• amoeboid
• amyloid
• aneroid
• anthropoid
• arachnoid
• asteroid
• benzenoid
• carcinoid
• celluloid
• coronoid
• humanoid

Medical 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

alkaloidal

ˌal-kə-ˈlȯid-ᵊl 

adjective