Maximum concentration of alkaloids in Cinchona is found in

The maximum concentration of alkaloids in Cinchona is found in Barks.
Cinchona, (genus Cinchona), is a genus of about 23 species of plants, mostly trees, in the madder family (Rubiaceae), native to the Andes of South America.
Cinchona bark contains quinoline alkaloids. Quinine, quinidine, cinchonine and cinchonidine are the major substances among over thirty others. The bark of some species contains quinine which is useful against malaria.