A random walk through a cannabis field.

The present overview covers various aspects of research going on in the Cannabis field in the Department of Natural Products at the Hebrew University. In the first part we discuss, and try to explain, the reason for the absence of the term Cannabis (and possibly also opium) in the Old Testament. In the second part we bring evidence that, contrary to widely held views, stereospecificity of cannabinoid action is extremely high, and in certain cases almost absolute. Previous results seem to have been due to impurities in the samples tested. (+)-Delta-1-THC, (+)-delta-6-THC and (+)-7-hydroxy-delta-6-THC, when purified sufficiently, exhibit activity of about 1% of that of the natural (-) enantiomers. A new labelled cannabinoid ligand has been prepared by catalytic reduction of (-)-7-hydroxy-delta-6-THC dimethylheptyl. The equatorial C-1 epimer obtained binds to the cannabinoid receptor with a KI of 40 pM. This compound is one of the most active cannabinoids tested so far for binding to the canabinoid receptor, and may become an important tool in cannabinoid research.