Bernard Richard

Alkaloids of Alstonia angustifolia

Abstract Thirty-one alkaloids have been isolated from the leaves and from the stem bark of Alstonia angustifolia from Malaysia. Twenty of them were known compounds: yohimbine, O -acetyl yohimbine, pleiocarpamine, fluorocarpamine, cathafoline, cabucraline, N -1 desmethylquaternine, vincamajine, normacusine B, lochnerine, affinisine, akuammicine, 11-methoxyakuammicine, antirhine, alstonisine, alstonerine, alstophylline, macralstonine, villalstonine and tetrahydrocantleyine. Among the 11 novel alkaloids, three were monomers: 19,20-dehydro-10-methoxytalcarpine, 19,20-dehydro- O -acetyl yohimbine and hydroxystrictamine, and eight were dimers: villalstonine N -4′-oxide, 10-methoxy villalstonine, 10-methoxyvillalstonine N-4′-oxide, 10-methoxymacrocarpamine, 10-methoxymacrocarpamine N -4′-oxide, angusticraline, alstocraline and foliacraline. Structural elucidation of the new alkaloids was based on spectral data analysis including high field 1 H and 13 CNMR.

Alkaloids from leaves and root bark ofErvatamia hirta

Abstract During chemical investigation of the leaves and root bark of Ervatamia hirta , 33 alkaloids were isolated. Seven are new: six are the ‘monomeric’ alkaloids ( E ) 16- epi -normacusine B , ( E ) 16- epi -affinisine, O -acetyl-16- epi -affinisine, affinisine- N (4)-oxide, dehydro-16- epi -affinisine, norfluorocurarine- N (4)-oxide, and the seventh is the bisindole 16-decarbomethoxyvoacamine-pseudoindoxyl. The known alkaloids are: ( E ) 16- epi -isositsirikine, β-yohimbine, yohimbine, 19,20-dehydro-β-yohimbine, β-yohimbine-pseudoindoxyl, isositsirikine, 19,20-dihydroisositsirikine, β-yohimbine-oxindole, normacusine B , affinisine, vobasine, dregamine, tabernaemontanine, norfluorocurarine, 12-hydroxynorfluorocurarine, apparicine, 3,14-dihydroellipticine, antirhine, voacristine, ibogaine, i☐ygaine, i☐ygaine-hydroxyindolenine, iboluteine, 4′,17,(17β)-dihydrotchibangensine, 16-decarbomethoxyvoacamine and 19,20-dihydro-16-decarbomethoxyvoacamine. Structural elucidation of the new alkaloids is based on spectral data and chemical correlations.

Alkaloids from stem bark and leaves of Peschiera buchtieni

Abstract During an investigation of the stem bark and leaves of Peschiera buchtieni , 34 alkaloids were isolated. Eight new alkaloids were obtained from the stem bark, N -methyl-pericyclivine, 18,19( R )-dihydroxycoronaridine, chloromethylene affinisinium, demethylaccedinisine, 18-hydroxyaffinisine, buchtienine, 3-hydroxytetrahydroolivacine and demethylceridimine. The known alkaloids from the stem bark were coronaridine, voaphylline, coronaridine hydroxyindolenine, heyneanine, eglandine, eglandulosine, 19-epi-heyneanine, voachalotine, ochropamine, olivacine, ibogamine, affinisine, N -oxyaffinisine, vallesamine, ( E )-isositsirikine, voaphylline hydroxyindolenine, normacusine B, janetine, 3,14-dihydroolivacine, 3′( R / S )-hydroxy- N -demethyl-tabernamine, 4′,17β-dihydrotchibangensine, ceridimine and N -demethyltabernamine. Apodine, voacristine, voacristine hydroxyindolenine and olivacine were identified in leaves.

Lotusine G: a new cyclopeptide alkaloid from Zizyphus lotus

In addition to six cyclopeptide alkaloids lotusines A-F, a new compound lotusine G, was isolated from the root bark of Zizyphus lotus by centrifugal partition chromatography.

Alkaloids of Alstonia lanceolifera

Abstract Four new indole alkaloids, 10-methoxydeplancheine, 10,11-dimethoxy-1-methyl-deacetyl picraline benzoate, 10,11-dimethoxy-1-methyl-deacetyl picraline 3′,4′,5′-trimethoxybenzoate and 10,11-dimethoxy-1-methyl-deacetyl picraline were isolated from the leaves of Alstonia lanceolifera .

Four cyclopeptide alkaloids from Zizyphus lotus

Abstract Cyclopeptide alkaloids were isolated from the root bark of Zizyphus lotus . The structures of two new compounds, lotusine A and lotusine D, were elu

Alkaloids from alstonia undulifolia

Abstract (+)-Tetrahydrocantleyine, (−)-cantleyine, (−)-akuammicine, pleiocarpamine, echitamidine, 20- epi -19 & xi;-echitamidine, echitamine, nor-echitamine and undulifoline, a new alkaloid with the rare uleine skeleton, have been isolated from the stem bark of Alstonia undulifolia . The structures were established by spectroscopic means.

Alkaloids from leaves and stem bark of Ervatamia polyneura

Abstract Twenty-three alkaloids were isolated from leaves and stem bark of Ervatamia polyneura, four of which are new: vobasenal, 16-epivobasenal, 3-oxo-19-epiheyneanine and 3-hydroxy-3,4-secocoronaridine. The other alkaloids are the known pericyclivine, vobasine, vobasine N-(4)-oxide, 16-epivobasine, vobasinol, dregamine, perivine, anhydrovobasindiol, apparicine, (+) tubotaiwine, voaphylline, 3, 14-dihydroellipticine, coronaridine, eglandine, eglandulosine, heyneanine, 19-epiheyneanine, voacangine and coronaridinehydroxyindolenine. Structural elucidation of the new alkaloids was based on spectral data.

Alkaloids of Alstonia lanceolata

Abstract Thirteen alkaloids were isolated from the stem bark of Alstonia lanceolata . They were lochnericine, gentianine, 10,11-dimethoxy-1-methyl-deacetylpi

Chemical compounds from Eperua falcata and Eperua grandiflora heartwood and their biological activities against wood destroying fungus (Coriolus versicolor)

AbstractThe chemical analysis of the compounds present in dichloromethane and ethanolic fractions as well as bioassays enable to understand the differences in the durability of Eperua falcata and Eperua grandiflora. The main distinction between these two species is the acidic subfraction of diterpenoid extract, which is antifungal in Eperua falcata when tested under in-vitro conditions. This study also shows that ethanolic fraction plays an important role in the mechanism of natural durability. Furthermore, it reports the first isolation of cativic acid in Eperua falcata wood. ZusammenfassungAnhand chemischer Analyse der in Dichlormethan- und Ethanolfraktionen vorhandenen Verbindungen sowie biologischer Prüfungen können die Unterschiede in der Dauerhaftigkeit von Eperua falcata und Eperua grandiflora aufgezeigt werden. Der Hauptunterschied zwischen den beiden Arten besteht in der sauren Fraktion des Diterpenoid-Extraktstoffes, der sich bei Prüfungen unter in-vitro Bedingungen bei Eperua falcata als pilzwidrig erwies. Anhand dieser Arbeit konnte auch gezeigt werden, dass die Ethanolfraktion eine wichtige Rolle bezüglich der natürlichen Dauerhaftigkeit spielt. Darüber hinaus wird über die erstmalige Isolierung von Cativinsäure aus Eperua falcata Holz berichtet.