Quinine side effects include deafness, low blood platelets, and an irregular heartbeat. Use can make one more prone to sunburn. While it is unclear if use during pregnancy causes harm to the baby, use to treat malaria during pregnancy is still recommended. Quinine is an alkaloid, a naturally occurring chemical compound. How it works as a medicine is not entirely clear. Quinine was first isolated in 1820 from the bark of a cinchona tree. Bark extracts have been used to treat malaria since at least 1632. It is on the World Health Organization's List of Essential Medicines, the most effective and
Bark (botany) the ground to where the main branching starts) of the tree. Bark tissues make up by weight between 10–20% of woody vascular plants and consists of various biopolymers, tannins, lignin, suberin, suberan and polysaccharides. Up to 40% of the bark tissue is made of lignin which forms an important part of a plant providing structural support by crosslinking between different polysaccharides, such as cellulose. Condensed tannin, which are in fairly high concentration in bark tissue, is thought to inhibit decomposition. It could be due to this factor that the degradation of lignin is far less pronounced in bark tissue than