Having been used as a folk remedy for centuries, studies in the 1950s revealed that the rosy periwinkle "Catharanthus roseus" contained over 120 alkaloids, many of which are biologically active, the two most significant being vincristine and vinblastine. While initial studies for its use in diabetes mellitus were disappointing, the discovery that it caused myelosuppression (decreased activity of the bone marrow) led to its study in mice with leukemia, whose lifespan was prolonged by the use of a vinca preparation. Treatment of the ground plant with Skelly-B defatting agent and an acid benzene extract led to a fraction termed "fraction A". This fraction was further treated with aluminium oxide, chromatography, trichloromethane, benz-dichloromethane, and separation by pH to yield vincristine.