Definition of alkaloid in English:


Translate alkaloid into Spanish


  • Any of a class of nitrogenous organic compounds of plant origin which have pronounced physiological actions on humans. They include many drugs (morphine, quinine) and poisons (atropine, strychnine).

    ‘Other important alkaloids are caffeine, ricinine, and quinine.’
    • ‘Morphine is an alkaloid, meaning that it is an organic compound that contains carbon, hydrogen and nitrogen, and forms a water-soluble salt.’
    • ‘This material is a complex mixture of about 20 different alkaloids or nitrogen containing organic bases.’
    • ‘The cinchona tree contains more than 20 alkaloids of which quinine and quinidine are the most important.’
    • ‘Barbiturates are derived from barbituric acid, an alkaloid with nitrogen-containing rings.’
    • ‘Caffeine is a naturally occurring drug belonging to a group of compounds called alkaloids.’
    • ‘The isolation of morphine from opium takes advantage of the amphoteric nature of the alkaloid, since morphine is a phenolic amine.’
    • ‘Key alkaloids present in goldenseal include berberine, hydrastine, and canadine.’
    • ‘The alkaloids in poppy include morphine, narcotine and codeine - the reasons why opium is used most frequently as a sedative.’
    • ‘Many multicellular trichomes are glandular, developing a terminal gland which may secrete a variety of compounds, such as alkaloids to deter or poison predators.’
    • ‘Caffeine is a bitter alkaloid found especially in coffee, tea, and kola nuts and used medicinally as a stimulant and diuretic.’
    • ‘CE analysis of plant secondary metabolites such as flavonoids, alkaloids, and phenolic acids is now common.’
    • ‘Plant or vinca alkaloids are derived from plants and block cell division during mitosis.’
    • ‘Second, the alkaloid is refluxed with acetic anhydride for about five hours.’
    • ‘They are precursors of benzoic phenanthridine alkaloids, active ingredients of many medicinal plant extracts.’
    • ‘At present, the chemical components of this water extract are thought to include only alkaloids, terpenes and pigments.’
    • ‘Berberine is an alkaloid occurring in the plant genera Berberis and Coptis.’
    • ‘Prominent examples are quinolizidine alkaloids, gossypol, glucosinolates, nonproteinogenic amino acids and furanocoumarins.’
    • ‘Terpenoid indole alkaloids absorb UV radiation and are implicated as having a UV-protective role in plants.’
    • ‘Diuretics can be found in terpenes, phenolics and alkaloids.’



/ˈalkəˌloid/ /ˈælkəˌlɔɪd/


Early 19th century coined in German from alkali.