Capsaicin-Producing Plants: Species Diversity, Distribution and Botanical Details

The species of Capsicum are known to synthesise capsaicin. It has a molecular weight of 305.5 g/mol and the chemical formula C18H27NO3. The IUPAC name of capsaicin is (E)-N-[(4-hydroxy-3-methoxyphenyl)methyl]-8-methylnon-6-enamide. It is responsible for the unique pungent taste of the Capsicum. It is crystalline, colourless, odourless and lipophilic. This molecule belongs to a special type of alkaloids called capsaicinoids. Capsicum spp. are known to produce several types of capsaicinoids such as capsaicin, homocapsaicin, dihydrocapsaicin, nordihydrocapsaicin, homodihydrocapsaicin and norcapsaicin. Capsaicin and dihydrocapsaicin constitute about 80–90% of capsaicinoids and hence are the major capsaicinoids of the Capsicum. The only genus that has been found to produce and accumulate capsaicinoids is Capsicum. Capsaicin concentration in plants varies and is generally affected by genetic, environmental and various other factors including biotic stresses. The capsaicin finds applications in diverse sectors including flavouring, food, cosmetics, defence sprays, medicine and pharmacy. This book chapter provides a brief overview of the diversity of various capsaicin-producing plants along with their botanical, cytological and distribution details. This chapter is important for those who are interested in botany, taxonomy and diversity of the capsaicin-producing species.