G Muriuki

A clerodane diterpene and other constituents of Croton megalocarpus

Abstract A novel clerodane-type furano-diterpene with the 9,10-abeo-methyl group has been isolated from Croton megalocarpus as a major constituent. Structure elucidation has been achieved by a combination of spectroscopic measurements including 2D-NMR and NOE experiments, on the parent compound as well as the monoacetyl derivative. Lupeol, betulin, β-sitosterol and long-chain aliphatic esters were also found and characterized.

Effects of the active constituents of Catha edulis on the neuromuscular junction

(-)-Cathinone and d-norpseudoephedrine (DNE) in the dose range 0.2-1.2 mg/ml produced a reduction in contractions of skeletal muscle, evoked by direct and indirect electrical stimulation and antagonised the facilitatory action of physostigmine on the neuromuscular junction; but failed to antagonise a partial blockade induced by d-tubocurarine (dTb) as occurs with norepinephrine or epinephrine. The local anaesthetic actions of (-)-cathinone and DNE were found to be almost equivalent to that of lignocaine. These results indicate that (-)-cathinone and DNE may have a direct blocking action on the neuromuscular junction, which is independent of cholinergic and adrenergic transmission.