Marc Litaudon

Bisnicalaterines B and C, atropisomeric bisindole alkaloids from Hunteria zeylanica, showing vasorelaxant activity.

Two new bisindole alkaloids, bisnicalaterines B and C (1 and 2) consisting of an eburnane and a corynanthe type of skeletons, were isolated from the bark of Hunteria zeylanica. Their absolute structures were determined by combination of NMR, CD, and computational methods, and each of them was shown to be in an atropisomeric relationship. Bisnicalaterines B and C (1 and 2) showed potent vasorelaxant activity on isolated rat aorta.

Naucline, a New Indole Alkaloid from the Bark of Nauclea officinalis

A new indole alkaloid, naucline (1) together with four known alkaloids, angustine (2), angustidine (3), nauclefine (4) and naucletine (5), were isolated from the bark of Nauclea officinalis. The structures of all isolated compounds were elucidated with various spectroscopic methods such as 1D- and 2D- NMR, IR, UV and LCMS-IT-TOF. In addition to that of alkaloid 1, the complete 13C-NMR data of naucletine (5) were also reported. Naucline (1) showed a moderate vasorelaxant activity (90% relaxation at 1 × 10−5 M) whereas, angustine (2), nauclefine (4), and naucletine (5) showed potent vasorelaxant activity (more than 90% relaxation at 1 × 10−5 M) on an isolated rat aorta.

(+)-Kunstlerone, a new antioxidant neolignan from the Leaves of Beilschmiedia kunstleri gamble.

A new neolignan, 3,4-dimethoxy-3′,4′-methylenedioxy-2,9-epoxy-6,7-cyclo-1,8-neolign-11-en-5(5H)-one, which has been named (+)-kunstlerone (1), together with six known alkaloids: (+)-norboldine (2), (+)-N-methylisococlaurine (3), (+)-cassythicine (4), (+)-laurotetanine (5), (+)-boldine (6) and (-)-pallidine (7), were isolated from the leaves of Beilschmiedia kunstleri. The structures were established through various spectroscopic methods notably 1D- and 2D-NMR, UV, IR and LCMS-IT-TOF. (+)- Kunstlerone (1) showed a strong antioxidant activity, with an SC50 of 20.0 µg/mL.

3′,4′ Dihydronorstephasubine, a new bisbenzylisoquinoline from the bark of Alseodaphne corneri

A new bisbenzylisoquinoline, 3,4-dihydronorstephasubine (1) together with two known alkaloids, norstephasubine (2) and gyrolidine (3) were isolated from the stem bark of Alseodaphne corneri (Lauraceae). The 13 C-NMR data for norstephasubine (2) and gyrolidine (3) were also reported. Structural elucidation of 1 was performed by spectral methods such as 1D- and 2D- NMR, IR, UV, and HRMS. 3,4-Dihydronorstephasubine (1) and gyrolidine (3) showed moderate vasorelaxant effect on rat aorta.

N-Cyanomethylnorboldine: A New Aporphine Isolated from Alseodaphne perakensis (Lauraceae)

A phytochemical study of the bark of Alseodaphne perakensis has yielded three aporphine alkaloids: the new compound N-cyanomethylnorboldine (1), and the two known alkaloids N-methyllaurotetanine (2) and norboldine (3). The isolation was achieved by chromatographic techniques and the structural elucidation was performed via spectral methods, notably 1D- and 2D-NMR, UV, IR, and HRFABMS. The vasorelaxation activity of compound 1 has been studied.

α'-oxoperakensimines A-C, new bisbenzylisoquinoline alkaloids from Alseodaphne perakensis (Gamble) Kosterm

Three new bisbenzylisoquinolines, α-oxoperakensimines A - C (1 -3) have been isolated from the bark of Alseodaphne perakensis (Gamble) Kosterm (Lauraceae). Their structures were elucidated by two-dimensional NMR techniques. α-Oxoperakensimines A - C (1 - 3) showed vasorelaxant activity on rat aorta.

Grandine A, a New Proaporphine Alkaloid from the Bark of Phoebe grandis

The stem bark of Phoebe grandis afforded one new oxoproaporphine; (–)-grandine A (1), along with six known isoquinoline alkaloids: (–)-8,9-dihydrolinearisine (2), boldine, norboldine, lauformine, scortechiniine A and scortechiniine B. In addition to that of the new compound, complete 1H- and 13C-NMR data of the tetrahydroproaporphine (–)-8,9-dihydrolinearisine (2) is also reported. The alkaloids’ structures were elucidated primarily by means of high field 1D- and 2D-NMR and HRMS spectral data.