In, G. Chesher, P. Consroe and R. Musty (eds.), Marihuana.
Australian Gov’t., Canberra. 1988. Pp. 263-270.
Jocelyn C. Turner & Paul G. Mahlberg
Department of Biology
Bloomington, Indiana 47405 USA
Keywords: Cannabis sativa, Cannabaceae, precursors, cannabinoids, seedling, olivetol
This study examined the incorporation of labeled exogenous precursors in cannabinoid biosynthesis by Cannabis. Shoot apices, cut from 72 hr and 20 day seedlings grown in a growth chamber at 25°C under a 20hr/4 hr light/dark cycle, were immersed at designated intervals into vials of either ul4c-sucrose (5-15 mCi/mM) or l’,2’-3H-olivetol (0.04 Ci/mM) as well as control conditions. Extracted cannabinoids were analyzed by chromatographic and scintillation techniques. Seedlings incubated 2 hr in sucrose incorporated label into all carboxylated (acid) and decarboxylated (neutral) cannabinoids and were detected immediately following the pulse with highest specific activity present after a 22 hr chase. Acid and neutral forms of cannabichromene (CBC), cannabigerol (CBG) and -1;9. tetrahydrocannabinol (THC) were present after all chases. Seedlings incubated 2 hr in olivetol incorporated label into acid and neutral CBC, CBG and THC with highest specific activity at O chase period. A lower specific activity was detected for CBC than CBG and THC although CBC was present in greatest quantity. Seedlings readily incorporated and carboxylated precursors to form cannabinoids. The pattern of incorporation indicated that a bifurcation in the pathway leading to cannabinoid formation was present in the developing plant.