Quinine – From the Sacred Bark to a Wonder Drug
Chapter 4.
Quinine and the Yellow Cinchona
The active ingredient in Talbor’s secret recipe was certainly an easy one to figure out. In contrast, identifying the active component of the cinchona bark was a much more challenging task. It remained unknown until Pierre Pelletier and Joseph Caventou, two accomplished French pharmacists and scientists, isolated it in 1820, almost 200 years after Jesuits powder was first introduced in Europe in the 1630s.
This important work was done in their laboratory in the back of a Parisian apothecary shop. There are several different kinds of cinchona bark. Pelletier and Caventou studied extracts from six varieties of the cinchona tree, including the grey cinchona, yellow cinchona, and red cinchona. The substance that made them famous was found in the bark of the yellow cinchona. The isolation process was not easy. The bark powder was first mixed with alcohol, then rinsed with a hot solution of hydrochloric acid, leading to a purified extract which was a white powder after being washed and dried. Later steps involved dissolving the white powder in alcohol. After the clear alcohol extract was evaporated, the undissolved part was a pale-yellow gummy substance, a bitter-tasting alkaloid. They named it quinine based on the Indian word “quina-quina”, the native name of the cinchona tree. Interestingly, when they used the same procedure for grey cinchona, the substance they obtained would not be quinine but another alkaloid, cinchonine. On the other hand, both quinine and cinchonine are present in the red cinchona tree.
Considering the enormous population infected with malaria in the 19th century, Pelletier and Caventou could have been very rich had they patented their method of quinine isolation. However, they gave up a fortune in doing so and chose a different route – instead of filing a patent, they invited other researchers to verify the therapeutic properties of quinine as soon as possible. For such an important discovery, the only money they had ever received was a small sum of 10,000 francs from the French Institute of Science in 1827.
Pelletier and Caventou’s quinine extraction method became well-known and was soon used by many pharmacists. Based on their method, many firms began to manufacture quinine commercially. The demand for cinchona bark skyrocketed. By the 1840s, millions of tons of cinchona bark were exported to Europe from the Andean republics. The native suppliers chopped down one tree after another. Because of reckless stripping of the forests, cinchona trees became increasingly scarce. It became more difficult to find species with sufficient quinine content in the bark.
In 1844, Bolivia passed laws to prohibit the collection and export of seeds and plants without a license; the aim was to protect their monopoly and prevent smuggling because 15% of the country’s tax revenue came from bark exports. The two main colonial powers, England and Holland, were unhappy with the situation and wanted to move the cultivation of cinchona trees to their colonial territories. During their race to see who would be the first to establish cinchona plantations outside of South America, stories came along, as shown in the next chapter.
[Written by Guohua An; Copyrighted content]