In 1905, Paul Carnot proposed the idea that a hormone regulates the production of red blood cells. After conducting experiments on rabbits subject to bloodletting , Carnot and his graduate student Clotilde-Camille Deflandre  attributed an increase in red blood cells in rabbit subjects to a hemotropic factor called hemopoietin. Eva Bonsdorff and Eeva Jalavisto called the hemopoietic substance 'erythropoietin'. Reissman and Allan J. Erslev demonstrated that a certain substance, circulated in the blood, is able to stimulate red blood cell production and increase hematocrit . This substance was purified and confirmed as erythropoietin.  
Constituents of the colocynth fruit and leaves ( Citrullus colocynthis ) include cucurbitacins.   The 2-O-β-D- glucopyranosides of cucurbitacins K and L can be extracted with ethanol from fruits of Cucurbita pepo cv dayangua .  Pentanorcucurbitacins A and B can be extracted with methanol from the stems of Momordica charantia .  Cucurbitacins B and I, and derivatives of cucurbitacins B, D and E, can be extracted with methanol from dried tubers of Hemsleya endecaphylla .