belladonna bĕlədŏn´ə [key] or deadly nightshade, poisonous perennial plant, Atropa belladona, of the nightshade family. Native to Europe and now grown in the United States, the plant has reddish, bell-shaped flowers and shiny black berries. Extracts of its leaves and fleshy roots act to dilate the pupils of the eye and were once used cosmetically by women to achieve this effect. (The name belladonna is from the Italian meaning
beautiful lady.) The plant extract contains the alkaloids atropine, scopolamine, and hyoscyamine. Belladonna has also been used since ancient times as a poison and as a sedative; in medieval Europe large doses were used by witchcraft and devil-worship cults to produce hallucinogenic effects. Other species of the potato family such as henbane (Hyoscyamus niger), mandrake (Mandragora officinarum), and Jimson weed (Datura stramonium) also contain one or more of the alkaloids present in belladona. The active substances act physiologically to depress the parasympathetic nervous system. Belladonna is classified in the division Magnoliophyta, class Magnoliopsida, order Solanales, family Solanaceae.
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