Although the majority of compounds screened were of synthetic origin, one chemist, Jonathan Hartwell, who was employed there from 1958 onwards, had  experience with natural product derived compounds, and began a plant screening operation. After some years of informal arrangements, in July 1960, the NCI commissioned the United States Department of Agriculture (USDA) botanists to collect samples from about 1,000 plant species per year. On 21 August 1962, one of those botanists, Arthur S. Barclay, collected bark from a single Pacific yew tree in a forest north of the town of Packwood, Washington, as part of a four-month trip to collect material from over 200 different species. The material was then processed by a number of specialist CCNSC subcontractors, and one of the trees samples was found to be cytotoxic in a cellular assay on 22 May 1964.Accordingly, in late 1964 or early 1965, the fractionation and isolation laboratory run by Monroe E. Wall in Research Triangle Park, North Carolina, began work on fresh Taxus samples,  isolating the active ingredient in September 1966 and announcing their findings at an April 1967 American Chemical Society meeting in Miami Beach. They named the pure compound taxol in June 1967. Wall and his colleague Wani published their results, including the chemical structure, in 1971.The NCI continued to commission work to collect more Taxus bark and to isolate increasing quantities of taxol.
In the U.S., it is a Schedule II Narcotic controlled substance with a DEA ACSCN of 9220 and 2013 annual aggregate manufacturing quota of 4.5 kilos. The salts in use are the tartrate (free base conversion ratio 0.58) and hydrobromide (0.76). See also
Cough syrup
Racemorphan; Dextrorphan;
Noscapine
Codeine; Pholcodine
Dextromethorphan; Dimemorfan
Butamirate
Pentoxyverine
Tipepidine
Cloperastine; Levocloperastine


== References ==