In 1947 Sir Robert Robinson received the Nobel prize for Chemistry "in recognition of his investigations of plant products of biological importance, especially the alkaloids". This powerful family of plant chemicals was proving a potent medical tool.

Professor Kathy Willis traces the natural role of alkaloids in plants and the first attempts to isolate one of the best know - quinine, from chinchona bark growing in the Andes. This development gave rise to the emergence of a new kind of laboratory scientist equally able to handle botanical and chemical data. As Mark Nesbitt, Keeper of Kew's Economic Botany Collection explains, this was to eliminate the chance and guesswork in identifying "good" plants from "bad".

Professor Monique Simmons of Kew's Jodrell Laboratory, assesses why chemicals from the plant kingdom are still needed in the fight against some of our most challenging diseases, from breast cancer to cardiovascular disease, and how making the nuanced connections between plant species is central to success in this field.

Producer Adrian Washbourne.