Pareira is a wooded vine frequently found on several tall trees. This plant has a smooth texture and it may grow up to a length of one foot (30 cm). Pareira has a gray-hued, crumpled stem and a portion of it may possibly be covered with lichens. The roots of the plant are blackish-brown and they are solid, heavy as well as knotty. The color inside the roots is reddish-yellow. This woody vine bears berry-like fruits whose color may be scarlet or black.
Here is an ancient scene that has been oft repeated in one or the other form for centuries displaying the therapeutic property of this vine. A native Indian is stalking a little deer deep inside the dense Amazon rain forest. The deer shows indecision for a while and sniffs the breeze. At the same time, the Indian lifts up an elongated blow gun near his lips and after puffing in some air, he shoots a dart whose tip is poisoned with a herbal. The deer is shocked and jumps into the undergrowths, as the hunter follows the prey. Soon, the hunter discovers his victim, which has been numbed and is dying due to asphyxiation (stifling).
Although this often repeated scene may appear to be unconnected with the disinfected background of a state-of-the-art operation theatre somewhere in North America, where qualified surgeons undertake subtle abdominal operations, they are actually related. The connecting link between the two is a medication called curare, which is an extract of the wooded stems of the vine pareira found growing on tall trees.
Pedro de-Cieza de Loon, a soldier from Spain, was the first to bear witness to curare’s use and usefulness. Sometime around 1540, he witnessed many people belonging to the native Indian tribes from places that now are in Brazil, Columbia, Ecuador, and Peru using poison head arrows to hunt animals for food and hide. According to this Spanish soldier, these tribal people dipped the tips of their arrows in a sticky substance. A year later, an explorer named Francisco de Orellana lost one of his mates to this type of poisoned arrow in 1541. Renowned English adventurer Sir Walter Raleigh carried one such poison arrow to England in 1595.
During the next few centuries, people witnessed a lot of juicy exaggeration regarding this puzzling poison brought from South America. There was much gossip regarding the source of this poison and people speculated that it could be snake venom, rare orchids or even boiled ants! Numerous expeditions undertaken to this region discovered exciting pieces of information regarding the poison – more than 20 tribal groups used curare and every one of them had dissimilar formulae; while some tribes applied the poison to the tip of the arrows, others to detachable arrow heads and some others to the tips of their wooden spears; some tribes stored the poison in bamboo tubes, some in pots and others in gourds; the mysterious poison killed victims by stifling (asphyxiating) them. Yet, none precisely knew what the poison was, the manner in which it was prepared or how it actually worked.
Finally, the truth was discovered in 1844. During experiments with frogs, Claude Bernard, a French physiologist, discovered that curare prevented the brain from sending nerve signals to the muscles, causing the muscles to relax to such an extent that they became numb. As the poison affects the muscles of the chest, the victim stops breathing. However, it was not till the early part of the 20th century that scientists became aware of the fact that while everyone prepared this poison with his individual secret formula, all the poisons were actually extracted from the stems of particular climbing vines and the extract from the pareira vine was most deadly.
Eventually when the scientists succeeded in isolating the alkaloid called tubocurarine, which is actually the active muscle relaxant of pareira vine, people associated with contemporary medicine started finding its application for different uses. This alkaloid has the aptitude to neutralize poisons that result in muscle contraction, including strychnine as well as tetanus toxins. When tubocurarine is employed to unwind the muscles connected to fractured or broken bones, this alkaloid makes it easy as well as safe for them to set again. Physicians have used tubocurarine for treating people affected by cerebral palsy and polio, in addition to treating epileptic seizures.
Tubocurarine finds its most common use in surgery, wherein it is administered intravenously together with different anesthetics with a view to make the muscles relax. When tubocurarine is used, the patient actually requires fewer amounts of anesthetics.
Root, stem, bark, leaf.
Pareira is popular for containing curare, the lethal poison used by the tribes in the Amazon basin on their arrow heads. Several famous explorers from Europe, counting Christopher Columbus and Sir Walter Raleigh came back from South America with numerous stories of how their men were killed by these ‘evil’ herbal products. In fact, curare is considered to be a silent killer that provided the native tribal populace with nearly a mystic advantage over their adversaries who were armed with guns. It is interesting to learn that in many countries, including the United States and Netherlands, the alkaloid tubocurarine extracted from pareira vine has been administered in the form of a deadly injection in euthanasia (mercy killing) and capital punishment. However, in a number of other countries, restrictions have been imposed on the use of tubocurarine.
Till this day, the pareira vine is the sole recognized source of deltatubocurarine, an alkaloid that is yet to be synthesized by scientists, who first isolated this substance way back in 1935. Usually, d-tubocurarine is administered in small doses together with general anesthesia with a view to cause muscle paralysis. This alkaloid derived from pareira works to obstruct the transmission of nerve impulses to the receptor sites on skeletal muscles. In addition, d-tubocurarine is also employed in shock therapy as well as in setting broken bones. A number of people, including inhabitants of Brazil, regard pareira to be a diuretic as well as a stimulant for the uterus and use it for these purposes. In fact, the Brazilians also use d-tubocurarine for treating bites by poisonous snakes.
Pareira is also a notorious herb because the poison depends on the consequence of its lethal offshoot that directly enters the bloodstream. However, internal consumption of pareira in the form of a remedy is practically safe provided you do not have any sores or cuts inside your mouth. The stems and roots of pareira have a bitter-sweet flavours and possess gentle laxative, stimulant as well as diuretic properties. In addition, this herb is also used to induce menstruation. The primary use of pareira is to alleviate chronic soreness of the tubules of the urinary system. As discussed above, people in Brazil also use pareira to treat poisonous snake bites. For this purpose, an infusion prepared from the roots of the vine is taken by mouth and, at the same time, the crushed leaves of this herb are applied topically on the site of the bites.
People in Peru and neighbouring Brazil use the roots of this wooded vine to enhance urination, lower fever and induce menstruation. In addition, plants yielding curare are also employed for treating edema, inflammation of the testicles and kidney stones. It is applied topically on contusions and bruises. A homeopathic remedy is also prepared using this herb to cure enlarged prostate and urinary tract inflammation. Several early explorers, including Sir Walter Raleigh have reported that the Indian herbalists have been using the curare vine to treat various health conditions since the 1500s and much later it was introduced into the European herbal medicine. British herbalist Maude Grieve, who authored the book ‘A Modern Herbal’ (published for the first time in 1931), reported that these plants work in the form of an antiseptic for the bladder when the urinary passage is affected by chronic inflammation. In addition, this herb is also recommended for people suffering from edema, jaundice, rheumatism, vaginal discharges as well as gonorrhea.
In fact, besides pareira, curare, which is used as a poison on arrow heads, is prepared from several other plants. In addition, different native Indian tribes inhabiting the Amazon basin use curare to prepare various recipes. Usually, the native Indians in Venezuela as well as those in the Guianas employ Strychnos plants in the form of the major ingredient, while the tribes in Ecuador, Brazil and Peru employ the curare vine called Chondrodendron tomentosum as the major constituent of the poisons prepared by them. In both instances, people generally combine the extracts of many dissimilar plants and often also add frog and snake venom to it to prepare the poisons.
Several Indian tribes in South America, such as the Ketchwas in Ecuador, Sionas in Colombia, and the Lamistas in Peru employ curare vine to prepare their deadly poisons. They first crush the stems and roots of these plants and then cook them together with other different plants as well as venomous animals. These substances are boiled for prolonged periods (at times for as many as two days at a stretch) till the substances turn into a dark-colored paste or syrup. Subsequently, the final product is used to smear the drafts they use in their blow guns and their hunting arrow heads. In fact, these poisons are not genuine toxins – instead they are very strong muscle relaxants.
Death due to curare poison is actually a result of asphyxia (stifling or respiratory arrest), as it makes the muscles to relax to such an extent that the muscles that regulate the lungs and diaphragm stop functioning. It is interesting to note that curare poison works only when the venom enters the bloodstream. Consuming curare poison and also consuming the meat of animals poisoned with curare does not have any toxic effect, since the stomach does not absorb this venom. Nevertheless, curare works wonderfully for the Indian hunters, as their prey is often located in an elevated position in the canopy – the action of the poison to relax the muscles thwart the animals from running away and it works to weaken or release their grasp on the tree branches, eventually making them fall on the ground. As soon as the poison enters the bloodstream of the prey, it starts acting instantly. However, death due to respiratory arrest or asphyxia may take some minutes in the case of birds as well as small animals, while it may take about 20 minutes or even more in the case of mammals, who generally have a larger body.
Habitat and cultivation
The wooded vine pareira is found growing mainly in the Amazon basin and Guianas. In addition, this plant also grows in the West Indies as well as other areas of South America. This vine thrives in areas having tropical or sub-tropical climatic conditions.
Scientists have undertaken extensive studies on pareira and Western medicine has also espoused the use of this woody vine as it possesses the potent aptitude to cause numbness.
Scientists were successful for isolating the alkaloid d-tubocurarine enclosed by pareira for the first time in 1897 and used it to prepare a medication from it in the early 20th century – precisely speaking, in 1935. De-tubocurarine works by obstructing the nerve impulses sent by the brains to the muscles signalling it to move. As a result of this, the entire body becomes so immobile that it is practically paralyzed. However, this alkaloid is not a toxin and the impact of this substance diminishes after roughly 90 minutes or so. Scientists introduced d-tubocurarine and curare into clinical anesthesia – which led to the commencement of the modern epoch of surgery. Currently, d-tubocurarine is marketed in the form of a prescription drug for use in the form of a common anesthetic. It is also used in the form of muscle relaxants that are employed in a variety of surgical forms. Administering d-tubocurarine enables the physicians to regulate the breathing of the patient by using different medications.
In addition, d-tubocurarine is used for treating paralysis due to tetanus – a condition that results in unmanageable contractions of muscles all over the body. Currently, scientists are evaluating the chemical conduits of this alkaloid as well as its actions for its function in obstructing transmission of serotonin, easing drug withdrawal symptoms, lessening vomiting as well as its anti-anxiety consequences. It has been found that d-tubocurarine also encourages histamine secretion. As histamine causes the blood vessels to dilate, its release may possibly lead to diminished blood pressure. D-tubocurarine is administered intravenously and this results in relaxing the muscles rapidly. It initially has an effect on the toes, eyes and ears and subsequently it effects the neck and the limbs. Eventually, it affects the respiratory system.
Chemical analysis of the pareira stem has revealed that it is loaded with alkaloids. The alkaloid that is mainly responsible for the muscle relaxing effects (the reason why it is used as a poison on the arrow heads) is known as d-tubocurarine.
The standard dosage of the pareira vine is one cup (250 ml) of a decoction prepared from the roots of the vine taken before having any food.
Side effects and cautions
Using curare may also lower the blood pressure and people with low pressure should not use it. In addition, people taking drugs to lower their blood pressure should also keep away from curare.