Liver cancer antiproliferative activity of a new nor-cucurbitacin from Mareya micrantha Müll. Arg.

Mareya micrantha Müll. Arg. (Euphorbiaceae) is a plant used in the Ivorian traditional medicinal system for various medical properties such as laxative, oxytocic, intestinal infectious diseases, malaria, etc. Six cucurbitacin derivatives (tetracyclic triterpenoids) are isolated from the leaves, stem barks or root barks of M. micrantha. Among these compounds, 29-nor-2ß,15α,20ß-trihydroxy-16α-acetyl-3,1,22-trioxo-cucurbita-4,23-diene (1) is a new nor-cucurbitacin isolated from the leaves; 29-nor-1,2,3,4,5,10-dehydro-3,15α,20ß-trihydroxy-16α-acetyl-11,22-dioxo-cucurbita-23-ene 2-O-ß-D-glucopyranoside (2) and 29-nor-2ß,15α,20ß-trihydroxy-16α-acetyl-3,11,22 trioxo-cucurbita-4,23-diene 2-O-ß-D glucopyranoside (3) are new nor-cucurbitacins recently discovered by us in leaves and isolated again for this study while dihydro-epi-isocucurbitacin D (4), tetrahydro-cucurbitacin I (5) and cucurbitacin L (6) are known cucurbitacins but newly isolated from the stem barks and the root barks of M. micrantha. Their chemical structures are established according to spectral data (UV, IR, MS and 1H, 13C NMR). Their antiproliferative activity is explored in vitro on the chemo-resistant human hepatocarcinoma cell line Hep3B. Compound 1 showed a strong and selective antiproliferative activity against this cancer cell line (IC50 value of 0.12 ± 0.05 µM) when compared to normal hepatocytes HepaRG.

Three novel non-nitrogenous cassane diterpenoids from Erythrophleum suaveolens (Guill. et Perr.) Brenan (Fabaceae).

During our research to contribute to the elucidation of the chemical composition of the root bark of E. suaveolens, six non-nitrogenous cassane diterpenoids (1-6) were isolated and identified. Of these secondary metabolites, three have never been previously described: Cassan-13,15-dien-3-oxo-17-oic acid (2), Cassan-15-en-[7,17]-γ-lactone (3) and 6α-hydroxy-cassamic acid (5). The other are known but, never isolated from the root barks of E. suaveolens (Fabaceae): Cassan-13,15-dien-17-oic acid (1), 6α-hydroxy-cassamic acid methyl esther (4) and cassamic acid (6). Their structures were established according to the spectroscopic data (NMR 1D and 2D, HR-ESI-MS and IR), in comparison with those of literature. The originality of this study lies in the fact that three new natural molecules were isolated and identified. In addition, all the isolated compounds (1-6) were reported for the first time from the root barks of E. suaveolens.