ABSTRACT
Biosynthetically they are related to indole alkaloids since both groups are derived from the same two precursors, tryptophan and loganin-a monoterpene iridoid. Quinoline alkaloids are particularly common among plants of the Rutaceae family. Isoquinoline alkaloids are most frequently found in the Papaveraceae, Berberidaceae and Ranunculaceae families. Alkaloids used in medicine are restricted largely to the Solanaceae family, apart from cocaine which comes from the coca plant in the Erythroxylaceae family. Symptoms of poisoning by tropane solanaceous alkaloids include dilated pupils, impaired vision, dryness of skin and secretions, extreme thirst, hallucinations and loss of consciousness. The primary actions of reserpine alkaloids are caused by inhibition of noradrenaline and depletion of amines in the central nervous system. While the hypotensive effects have a slow onset their duration is long, and the effective dose is sufficiently low to limit any side effects. Steroidal alkaloids are derived from triterpenoids, being distinguished from other compounds in that class by the presence of a nitrogen atom.
