Cathinone

• more affectionately (and chemically) known as beta-ketoamphetamine
• an amphetamine-like stimulant that is the primary psychoactive (does things to your brain) compound found in khat (Catha edulis), a flowering evergreen shrub that is native to East Africa
• is present mostly in the shoots and leaves (insert dry literary panda joke here) of the plant, which are often chewed or brewed into tea
  
• methcathinone, a synthetic designer amphetamine that became popular in Russia in the 1960s, is a methyl derivative of cathinone
• is converted into cathine and norephedrine, two less active amphetamine-like compounds, as the plant matures and when it is dried - hence fresh young plants contain the highest concentrations of cathinone, and so will produce the greatest stimulant effects

Ford M, Delaney KA, Ling L, and Erickson T. Clinical Toxicology. Philadelphia: W.B. Saunders Company, 2001.