Effect of indole alkaloids from roots of Rauvolfia ligustrina in the noradrenergic neurotransmission.

The new glucosyl sarpagan alkaloid designated as 21(R*)-(O-ß-glucosyl)-hydroxy-sarpagan-17-oic acid, along with eleven known alkaloids were isolated from a soluble alkaloidal fraction from the ethanol extract of Rauvolfia ligustrina. Their structures were elucidated by interpretation of spectroscopic data (1D and 2D NMR), HRESIMS experiment, GIAO 13C NMR calculations, and comparison with literature data. All the isolated alkaloids were screened by their neuroinhibitory effects using the electrically stimulated mice vas deferens bioassay. Compounds 1, 2 and 9 presented a potent inhibitory effect in the neurotransmission while 3 and 11 showed an acute neuroexcitatory effect. Compound 10 exhibited a very effective post-synaptic inhibitory activity.

Neuroinhibitory meroterpenoid compounds from Cordia oncocalyx.

Five new meroterpenoid compounds designed as rel-10ß,11ß-epoxy-2,11-dimethoxy-8α-hydroxy-8aß-methyl-5α,6,7,8,8a,9,10,10aß-octahydro-1,4-anthracendione (1), rel-10ß,11ß-epoxy-8α,5-dihydroxy-2-methoxy-8aß-methyl-5,6,7,8,8a,9,10,10aß-octahydro -1.4-anthracendione (2), rel-1,4,8α-trihydroxy-5-furanyl-2-methoxy-8aß-methyl-6,7,8, 8a,9,10-hexahydro-10-anthracenone (3), rel-10α,11α-epoxy-8α,11ß-dihydroxy-8aß-methyl-5ß,6,7,8,8a,9,10,10aß-octahydro-1,4-anthracenediol (4) and rel-1,4,8α-trihydroxy-5-carboxyethyl-2-methoxy-8aß-methyl-6,7,8,8a,9,10-hexahydro-10-anthra-cenone (5), besides seven (6-12) known compounds were isolated from the heartwood and sapwood ethanol extracts of Cordia oncocalyx. Moreover, the main isolated compounds were screened using the electrically driven mice vas deferens bioassay, which has a rich pharmacological receptors diversity.