Cinchona is the dried bark of the stem or the root of Cinchona calisaya, Cinchona ledgeriana, Cinchona officinalis, and Cinchona succirubra or hybrids of any of the first two species with any of the last two species; belonging to the family Rubiaceae. It is also referred as Peruvian or Jesuit’s bark; or Countess.
Plants are tropical shrubs or trees. Cinchona is native to Eastern slopes of the Andes at high altitudes (1500-2500 meters). It is known that the bark was first used as an antipyretic in 1630 by Jesuits, although it was discovered in 1513 in Peru. The efforts of the Viceroy of Peru made it introduced as a drug in Europe around 1655. It was reported as an infusion in London Pharmacopoeia first. After the discovery of quinine and cinchonine from it, the alkaloids or their mixture came into use as a medicine.
The natives of Peru were not familiar with the medicinal properties of the plant and hence looked at it with fear and suspicion because of its bitter taste. The bark came into evidence when the wife of Spanish governor was cured from malaria through the bark given to her. The bark went down in great demand and was collected by felling method without any new plantation.
General characteristic of stem bark and root bark are
Shape of the bark is curved, quill, or double quill. Outer surface is rough mainly due to longitudinal and transverse cracks, fissures, ridges and protuberences. Cracks and fissures are characteristic for each bark. Greyish patches of moss or lichen are present on the outer surface.
Colour of Cinchona succirubra is reddish brown while of other bark is yellowish to brown. Inner surface is striated and colour maybe reddish-brown to yellow. Odour is distinct and taste is bitter. One Allied drug is Cuprea bark obtained from Remijita pedunculata of family Rubiaceae.
Chemical constitution of Cinchona
Cinchona bark contains about 25 alkaloids, which belong to quinoline group. The important alkaloids are quinine, quinidine, cinchonine, cinchonidine. The alkaloids of lesser importance are quinicine, cinchonicine hydroquinine, hydrocinchonidine and homocinchonidine.
C.succirubra contains 5-7% of total alkaloids, of which is quinine. C.ledgeriana yields from 6-10% and in some cases, up to 14% with up to 75% being quinine. C.calisaya has 6-8% total alkaloids that are about 50% quinine.
Quinine and quinidine form many salts but medicinally their sulphates are more significant. Cinchonine and cinchonidine are also isomers of each other. Cinchona also contains quinic acid and cinchotannic acid. Cinchotannic acid decomposes into insoluble cinchona red, due to its phlobatannin nature. The bark also contains a glycoside called quinovin, tannins and bitter essential oil.
Health Benefits of cinchona bark
As an anti-malarial drug – quinine alkaloid of cinchona bark has anti-malarial properties. Quinine and its salts are used in the treatment of malaria. Quinine is a protoplasmic poison, especially for protozoa like Plasmodium vivax, Plasmodium falciparum, Plasmodium malariae and Plasmodium fatal and hence, used as a powerful antimalarial drug.
In malaria, quinine is effective against asexual cells only and not against gametes (sexual cells) so reoccurrence of attack takes place. This can be avoided if synthetic drugs like plasmoquine or chloroquine derivatives are used. The malarial parasites have become resistant to synthetic drugs and use of quinine has become important again.
The pharmacokinetic studies on quinine have shown that it can be better used in other forms. Infusion of quinine rather than intravenous injection eliminates the risk of sudden death. Secondly, quinine in microencapsulated form has been reported to give better bioavailability.
As a cardiac depressant – quinidine of cinchona bark acts as a cardiac depressant and is used to inhibit auricular fibrillation. It acts as a membrane stabilizing agent and shows negative inotropic action. It is used to prevent certain arrhythmias and tachycardia. Quinidine is regarded as highly valuable in prevention of atrial fibrillation.
Miscellaneous uses of Cinchona
- Quinine of cinchona bark is an anti-infective agent as well as an analgesic. It is used in cold sickness and flu.
- Cinchonidine of cinchona bark is used in rheumatism, neuralgia and sciatica.
- As an anti-spasmodic in whooping cough.
- Cinchona alkaloids are used as stomachic and bitter tonic. Cinchona preparations like cinchona extract, compound cinchona tincture etc. are also employed as bitter stomachics and antipyretics. It can cure indigestion and stomach disorders of the gastrointestinal tract.
- Quinine is used in U.S.A in the preparation of effervescent appetite stimulant tonic drinks.
- Quinine has also been found to be highly active in vitro against Trypanosoma cruzi epimastigotes.
- It is also used to cure different types of cancer like breast cancer, liver cancer, mesenteric cancer, cancer of spleen and other organs.
- Cinchona powder is used by many people as an astringent. Because of its astringency, it is also administered in toothpowders.
Probable therapeutic uses of Cinchona
There is insufficient evidence regarding the use of cinchona in treating hemorrhoids, varicose veins, leg cramps, muscle cramps, bloating and throat and lung diseases. Research is still going on to potentiate the given fact.
Cinchona : Side Effects and Precautions
Overdose of cinchona causes ringing of ears, headache, nausea, diarrhea and vision disturbances. It is responsible for causing bleeding and allergic reactions, including hives and fever. Large amounts of cinchona are unsafe and deadly.
Drugs containing quinine are strictly prescription drugs and should be sold only under the recommendation of a health practitioner. This is because of the quinine alkaloids present naturally, the consumption of which can cause serious side effects.
- Always look for warning signs and contraindications, while using higher level of quinine alkaloids.
- Do not use if you are pregnant or breast-feeding.
- Do not use if you have stomach or intestinal ulcers.
- If you are going for surgery within two weeks, do not use it as it might increase the risk of bleeding.
Cinchona has a long historical significance. It now occupies a major role in treating a lot many diseases. Although quinine alkaloids pose danger, a little dose is as such harmless if guided well under the medical practitioner. Because of its safety, it has now started to be used in ice-creams and baked foods too.