Historical aspects of antitumor compounds from plants, including homoharringtonine (Omacetaxine Mepesuccinate, SynriboTM)

Various preparations derived from vascular plants have been used utilized to treat tumors or cancerous conditions for centuries. The available literature was summarized by Jonathan Hartwell in a remarkable series of papers “Plants Used Against Cancer” published in Lloydia from 1967 to 1971. The U.S. National Cancer Institute (NCI) established the Cancer Chemotherapy National Service Center (CCNSC) in 1955. Hartwell transferred to CCNSC in 1957, and under his guidance a major program to discover plant anticancer constituents was developed. Arrangements were made between the NCI and the U.S. Department of Agriculture (USDA) for extensive plant collections in 1960. Many of the collections were from countries that were involved in the Food for Peace Program, Public Law (PL) 480. The Wisconsin Alumni Research Foundation (WARF) was awarded an extraction and screening contract, and research contracts were awarded to Drs. Monroe Wall, Morris Kupchan, Norman Farnsworth, John Cassady and others. When plant seeds were obtained, they were sent to the Northern Regional Research Laboratory (NRRL) in Peoria, Illinois, where they were examined in a program to identify potential new crops. Extracts of many of the seeds were prepared and screened for antitumor activity and the more significant results obtained from the seed extracts will be summarized.