Targeted Isolation of Hemitheion from Mostuea brunonis , a Proposed Biosynthetic Intermediate of Theionbrunonines

Elvis Otogo N’nang (1, 2) , Pierre Le Pogam (1) , Thiery Ndong Mba (2) , Cédric Sima Obiang (2) , Elisabeth Mouray (3) , Philippe Grellier (3) , Brice Kumulungui (2) , Pierre Champy (1) , Mehdi Beniddir (1)

1 BioCIS - Biomolécules : Conception, Isolement, Synthèse
2 USTM - Université des Sciences et Techniques de Masuku [Franceville, Gabon]
3 MCAM - Molécules de Communication et Adaptation des Micro-organismes

Hemitheion (1), a new sulfur-containing vobasane-type indole alkaloid, was isolated, together with three known compounds, vobasine (2), gelsedine (3), and gelsemicine (4), from the alkaloid extract of the stems of Mostuea brunonis Didr. (Gelsemiaceae). Compound 1 could be straightforwardly isolated. Its structure was elucidated by a combination of spectroscopic methods. Besides corresponding to a formerly postulated biosynthetic intermediate toward theionbrunonines, hemitheion (1) stands among the few monomeric vobasanes lacking an oxygen at C-3. Hemitheion (1) showed moderate antiplasmodial activity in the micromolar range against the strain FcB1 of Plasmodium falciparum and no cytotoxic activity against the MRC-5 cell line at 20 μM.

Domains: Chemical Sciences

Elvis Otogo N’nang, Pierre Le Pogam, Thiery Ndong Mba, Cédric Sima Obiang, Elisabeth Mouray, et al.. Targeted Isolation of Hemitheion from Mostuea brunonis , a Proposed Biosynthetic Intermediate of Theionbrunonines. Journal of Natural Products, 2021, 84 (4), pp.1409-1413. ⟨10.1021/acs.jnatprod.1c00143⟩. ⟨mnhn-03650071⟩