A QUINOLINE ALKALOID
Quinine has been discovered only recently to be a secondary metabolite of several Solomons Seals, such as
Whorled Solomon's-seal and Angular Solomon's-seal amongst others. Quinine was first found in the bark from the Chinchona tree, which grows natively in Peru, Bolivia and Chile and elsewhere. But it is now extracted from the bark of Remija because that is cheaper than Chinchona bark.
Quinine is a quinoline alkaloid (the two fused lower rings, one with a nitrogen atom in the ring). The other nitrogen atom of the molecule is within a bicyclic structure which your Author has drawn to resemble a 3-vaned paddle-wheel (top) [although its true 3-D structure is considerably warped]. The nitrogen-containing 6-membered polycyclic ring structure depicted near the top is reminiscent of the nitrogen-containing 7-membered polycyclic ring of the Tropane alkaloids.
Quinine is more famous for its use against malaria, at which it was quite effective. However, there were problems with the adverse effects of quinine and from 2006 the World Health Organisation no longer recommends it for such treatment when the more-effective and safer alternative called
Artemisin is available.
Your Author also remembers its widespread use for cramps of the calf muscles occurring during the night (which occurred quite frequently during Scout Camping trips in the 60's) but apparently quinine is now not thought safe enough for over-the-counter sales, and can now only be obtained by prescription. Quinine is a dangerous drug and although it might be appropriate for a life-threatening illness such as malaria, it is deemed unsuitable for less severe problems. Use for leg-cramps can result in life-threatening side effects! Your Author thinks that he had better dispose of the quinine tablets from his Scout first-aid kit.
The third famous use for quinine is in tonic water to which it imparts the bitter flavour. It was originally present at therapeutic levels (500mg to 1g per litre) for treating malaria, but nowadays tonic water contains much lower concentrations of quinine of the order of 83mg per litre. Tonic Water is very bitter and it is usually drunk as Gin and Tonic for a sweeter experience. Tonic water is fluorescent emitting light mostly of wavelength 460nm (blue/cyan) under UV illumination due to the
quinine contained within. In order to fluoresce it has to absorb photons of light at the wavelength of 350nm which is in the UVA band.
Quinine is a chemically basic amine and therefore forms salts. It is variously made as the hydrochloride, dihydrochloride, sulfate, bisulfate and gluconate. Clinical administration of the salt of quinine is orally. Quinine, as such, is never injected, but rather a
stereoisomer of quinine called
Quinidine. Quinidine is also found within Chincona bark (but your Author does not know if any Solomon's-seals follow suit).
THe common side effects of medicinal quinine are headaches, tinnitus, sweating and difficulty seeing properly. It can also make skin more susceptible to sunburn. More grave side effects include deafness, irregular heartbeat and low blood platelet count.