Jean Bruneton

Cytotoxic coumarins from Calophyllum dispar

Six coumarins have been isolated from the fruits and the stem bark of Calophyllum dispar (Clusiaceae). The structures of these minor components were established by means of spectroscopic analysis, including extensive 2D NMR studies. Some of these coumarins exhibited a significant cytotoxic activity against KB cells.

Trypanocidal Bisbenzylisoquinoline Alkaloids are Inhibitors of Trypanothione Reductase

Eleven bisbenzylisoquinoline (BBIQ) alkaloids were studied for in vitro trypanocidal activity against trypomastigote forms of the Y strain of Trypanosoma cruzi. The inhibitory activity of these compounds against trypanothione reductase (TR), a target enzyme for chemotherapy against Chagas disease, was also studied. Six BBIQ alkaloids (antioquine, cepharanthine, daphnoline, limacine, cycleanine and (-) curine) displayed a 50% lethal concentration (LC50) against T. cruzi of less than 100 microM. Daphnoline and curine, with LC50 values of 10 microM, are attractive for further investigation as potential anti-Chagasic drugs. Kinetic analyses suggested the BBIQ alkaloids are mixed inhibitors of TR. These compounds are reasonably potent inhibitors of TR; the best TR inhibitor, cepharanthine, had an IC50 of 15 microM, which is in the same order of magnitude as its LC50 against T. cruzi. The similar magnitudes of the IC50 and LC50 values suggest that inhibition of TR could contribute to the trypanocidal activity exhibited by the BBIQ alkaloids.

Thirteen New Xanthone Derivatives from Calophyllum caledonicum (Clusiaceae)

An EtOAc extract of the stem bark of Calophyllum caledonicum (Clusiaceae) yielded thirteen new hydroxylated and/or prenylated xanthone derivatives, namely 5-hydroxy-8-methoxyxanthone (1), 3,5-dihydroxy-1,2-dimethoxyxanthone (2), 1,8-dihydroxy-6,7-dimethoxyxanthone (3), 5,7-dihydroxy-2,6-dimethoxyxanthone (4), 6,8-dihydroxy-3,7-dimethoxy-xanthone (5), 2,5,6,7,8-pentahydroxyxanthone (6), 1,3,8-trihydroxy-5,7-dimethoxyxanthone (7) and according to a previously adopted nomenclature [3], caledonixanthone G-L. (8-13). The structural elucidation of 1-13 were mainly established on the basis of 1D and 2D NMR and HRMS spectroscopic analysis.

La criocerine: Nouvel alcaloide isole des tiges de Crioceras dipladeniiflorus

Abstract Seven indolic alkaloids have been isolated from the stem bark of Crioceras dipladeniiflorus . One of them is new and has been called criocerine. Its structure, 7, has been established by use of physical data and chemical correlation with [Δ 14 ]-vincamine.

Tirucallane triterpenes from the stem bark of Aglaia leucophylla

Abstract A new tirucallane triterpene, (−)-leucophyllone, was isolated from the stem bark of Aglaia leucophylla and its structure was elucidated from spectral data as 23( Z )-25-methoxy-tirucall-7,23-diene-3-one. In addition, (−)-caryophyllene oxide, (−)-niloticin, (−)-bourjotinolone and (−)-piscidinol were isolated from the same plant.

Alcaloïdes des ecorces de racines de Crioceras dipladeniiflorus

Abstract Eight alkaloids have been isolated from the root bark of Crioceras dipladeniiflorus. Five of them are new: Δ14-vincamine (I) epi-16 Δ14-vincamine (II) 12-methoxy-δ 14-vincamine (V) apo Δ14- vincamine (VI), and ditabersonine (VII), a dimeric alkaloid; the three others are known, voaphylline (III), tabersonine, (IV), and vobtusine (VIII).

The effect of bisbenzylisoquinoline alkaloids on Trypanosoma cruzi infections in mice

Five bisbenzylisoquinoline (BBI) alkaloids, curine, cycleanine, isotet:andrine, limacine and pheanthine were tested for trypanocidal activity in C 3H He mice infected with Y or CL strain of Trypanosoma cruzi. The activity was compared with the baseline drug, benznidazole. Oral treatment was more effective with curine at 10 mg/kg or with cycleanine at 2 mg/kg daily for 10 days in mice infected with Y or CL strain. In these groups, the parasitemias were negative after 5-7 weeks after inoculation and mortality time 50 (MT(50)) was significantly higher than untreated mice. Benznidazole was effective in mice infected with CL strain but not in mice infected with Y strain. The other BBI showed a relative efficacy against both strains. The effect of BBI alkaloids could be due to a blocking of the Ca2+ channel for the regulation of T. cruzi infectivity to invade host cells or their selective immunosuppressive properties.

Bis-benzylisoquinoline alkaloids from Abuta pahni

Abstract From the stems of Abuta pahni, eight isoquinoline alkaloids were isolated and identified by spectroscopic methods and chemical correlations. Three of the bis-benzylisoquinoline alkaloids are new and were assigned the structures 2′-N-nordaurisoline, 2-N-methyllindoldhamine and 2′-N-methyllindoldhamine. The other known alkaloids were coclaurine, daurisoline, lindoldhamine, dimethyllindoldhamine, stepharine and thalifoline.

ortho-Prenylphenol photooxygenation as a straightforward access to ortho-(2-hydroxy-3-methylbut-3-enyl)phenols

Abstract Photooxygenation (1O2) of ortho-prenylphenols followed by a reduction (PPh3) at low temperature (−30°C) yields a mixture of ortho-(2-hydroxy-3-methylbut-3-enyl)phenols and ortho-(3-hydroxy-3-methylbut-1-enyl)phenols. However, by running the two-step sequence at a higher temperature (15°C), the secondary allylic alcohol could be selectively recovered.

Alcaloides des feuilles du Crioceras dipladeniiflorus

Abstract Three alkaloids have been isolated from leaves of Crioceras dipladeniiflorus . Two of them, 12-methoxy-voaphylline and criophylline are new and their structures have been determined. The third has been identified as andrangine an alkaloid isolated recently from another Apocynaceae Craspidospermum verticillatum .