When the word "nicotine" is mentioned, most people think of cigarettes and tobacco. However, the tobacco plant is not the only plant that contains nicotine. According to the Australian Broadcasting Corporation, there are 66 other species of plant that contain nicotine. Most of these plants, including tobacco, belong to the Solanaceae, or nightshade, family.
The tobacco plant, Nicotiana tabacum, is cultivated for cigarettes. According to Dr. Duke's Phytochemical and Ethnobotanical Databases, part of the U.S. Department of Agriculture Research Service website, tobacco plant leaves contain between 20,000 and 40,000 parts per million of nicotine. This is much higher than the nicotine content found in most other plant species. Nicotiana rustica, known as mapacho in South America, and Nicotiana glauca, a species of wild tobacco, also contain high levels of nicotine.
The papaya plant, Carica papaya, contains nicotine, but the fruit itself does not. Unlike most plant sources of nicotine, papaya does not belong to the Solanaceae family. It is instead part of the Caricaceae family.
Belladonna, also known as deadly nightshade, is an extremely toxic plant. Both the leaves and berries contain a number of toxic alkaloids. Significant levels of nicotine are present in the leaves of Belladona.
According to the Science Daily website, nicotine alkaloids are also found in the leaves of the coca plant, which is native to South America. The coca plant, or Erythroxylum coca, is a member of the Erythroxylaceae family. Its leaves are used to make cocaine.
Duboisia, commonly known as the corkwood tree, is a small shrub native to Australia. There are four species of duboisia, one of which, the Duboisia hopwoodii, was used by Aboriginal Australians to make a drug called pituri. The stimulating effect of pituri was due to the nicotine, scopolamine and hyoscyamine contained within the leaves of the corkwood tree. "Of all the Aboriginal Australian nicotine-based drugs, pituri contained the highest percentage of nicotine," says the Drug Text website.
Common Edible Sources
Surprisingly, some common food sources contain nicotine. These include eggplant, tomatoes, potatoes, tomatillos, sweet peppers and hot peppers, all of which belong to the nightshade family. However, all of these food nightshades contain only trace amounts of nicotine. According to The World's Healthiest Foods website, eggplant is the food nightshade that appears to have the highest nicotine content after tobacco, but the amount of nicotine is greatly reduced.