Muscle relaxants Menispermaceae-curar

Bisbenzylisoquinolines (macrocyclic or linear, formed by 2 benzylisoquinolines) (+)-tubocurarine (macrocyclic) (acetylcholine (nicotinic) receptor antagonist and skeletal muscle relaxant major component of Chondrodendron species (Menispermaceae) pareira bark-derived curare arrow poison) dauricine (linear) (Menispermaceae curarelike anaesthetic) rodiasine (macrocyclic) (Ocotoea venenosa (Lauraceae) curare-like skeletal muscle relaxant) cepharanthine (macrocyclic) (Stephania species (Menispermaceae) anti-mycobacterial active against leprosy and tuberculosis). 

Menispermaceae contains many medicinal and toxic plants. Some of the South American Menispermaceae were used by native Indians for their curare activity [7]. The western world was introduced to the muscle relaxants by the Spaniards, who encountered these arrow poisons in 1514 [7, 95]. The main South American Menispermaceae species used to prepare pot/tube curare are Chondrodendron tomentosum, and three of the four known curarea genus, Curarea candicans, C. tecunarum and C. toxicofera [7]. 

Curare is a muscle relaxant drug, originally used as an arrow poison by Amazonian Indians. The traditional curare is prepared by a secret recipe thought to involve a number of plant species (Plotkin 1993). Plant sources of curare include Strychnos castelnaei and species in the Loganaceae family and Chondodendron tomentosum in the Menispermaceae family. Tubocurarine, a benzylisoquinoline dimer, is the major alkaloid in the curare plants. It exhibits paralysing effects on skeletal muscles, and is used as a muscle relaxant in surgical procedures. It controls convulsions caused by the toxic alkaloid strychnine. 

Muscle-Relaxant Activity of the Menispermaceae Associated with Curare and of Their Alkaloids... 

There is a very extensive literature on the pharmacology of curares and their active principles. The following references will provide an entry into the relevant literature Strychnos-hased curare and associated quaternary Strychnos alkaloids (41, 252, 481-484) Menispermaceae-based curare and associated alkaloids (252, 344, 345, 347, 353,419). It is not possible within the limits of this present Section to do more than briefly consider the toxicity and muscle-relaxant activity of curares and their active principles, as a prelude to Section 1.6 which outlines the development of some modern muscle relaxants. 

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