Science Cannabis

The Pharmacology of THC 35Adams's cannabidiol must have been due to contamination with THC.Nevertheless, Adams and his group were able to synthesize various chemicalderivatives of cannabidiol, including hydrogenated derivatives, thetetrahydrocannabinols, and some of these did possess potent psychoactiveproperties (measured both in human volunteers and increasingly by observingthe behavioral responses of rodents, dogs, and other laboratoryanimals). In his 1942 Harvey Lecture Adams wrote:The typical marijuana activity manifested by the isomeric tetrahydrocannabinolsconstitutes ponderable evidence that the activity of the plant itself,and of extracts prepared therefrom, is due in large part to one or otherof these compounds . . .(Adams, 1942)At the same time, across the Atlantic, despite the privations of war,research on cannabinoids continued in the chemistry department inCambridge England under the leadership of an outstanding organicchemist Alexander Todd, later to become Lord Todd. He and his colleaguesreisolated cannabinol, and capitalizing on the newly discoveredstructure of cannabidiol published by the Adams group, they were able tocomplete the identification of the chemical structure of this compoundstarted by Cahn (Todd, 1946). Both the Adams group and the Toddgroup went on to undertake the first chemical synthesis of cannabinol,and as part of this synthesis the Cambridge team actually made delta-9-tetrahydrocannabinol (THC) as an intermediate from which to form cannabinol.They commented on the high degree of biological activity thatthis compound possessed (assessed now by observing the characteristicbehavioral reactions of dogs and rabbits rather than human subjects).The Todd group repeatedly tried to prove that this compound or somethinglike it existed naturally in cannabis extracts. By repeated fractionationthey were able to prepare a highly active and almost colorless glassyresin that closely resembled synthetic tetrahydrocannabinol in its physicaland chemical properties. The techniques available then, however,were not powerful enough to determine whether this was a single chemicalsubstance or a complex mixture of closely related compounds. In areview article published in 1946 Todd wrote: