Alkaloids of Rauwolfia cumminsii stem

24 indole alkaloids were isolated from the stem bark of Rauwolfia cumminsii and 21 identified. The alkaloids comprised E-seco, sarpagan, dihydroindole, yohimbine, heteroyohimbine, 18-hydroxyyohimbine ester and anhydronium types together with peraksine and deacetylpicraline. The probable biosynthesis of the alkaloids is discussed.     

Stem alkaloids of Rauwolfia vomitoria

22 indole alkaloids were isolated from the stem bark of Nigerian Rauwolfia vomitoria and 20 characterized. The alkaloids comprised E-seco heteroyohimbine, sarpagan, dihydroindole, yohimbine and heteroyohimbine types. The biosynthetic relationship of the alkaloids is discussed.     

Alkaloids of Rauwolfia nitida root bark

Thirty-three indole alkaloids were isolated from the root bark of Rauwolfia nitida. Sarpagan, dihydroindole, indolenine, yohimbine, 18-hydroxy-yohimbine ester, heteroyohimbine and anhydronium base types were isolated. The principal alkaloids were reserpine (0.034%), serpentinine (0.033%), pseudoreserpine (0.013%) and reserpiline (0.012%).     

Alkaloids of Sri Lankan Strychnos nux-vomica

Twenty-two identified alkaloids have been isolated from the root bark and leaves of a Sri Lankan Strychnos species supplied as S. nux-vomica. T     

Quinoline and indolopyridoquinazoline alkaloids from Vepris louisii

The structures of two new 2-quinolone alkaloids from the stem bark of Vepris louisii, N-methylpreskimmianine [7,8 - dimethoxy - 3 - (3 - methylbut - 2 - enyl) - 1 - methyl - 2 - quinolone] and veprisine (7,8 - dimethoxy - N - methylflindersine) have been deduced from their spectral data and confirmed by partial synthesis from known compounds. Two minor indolopyridoquinazoline alkaloids were also isolated and identified as the already known 1-hydroxyrutaecarpine and the hitherto unknown 7,8-dehydro derivative of 1-hydroxyrutaecarpine.     

Alcaldoïes de Tabernaemontana brachyantha

From the trunk bark of Tabernaemontana brachyantha four alkaloids were isolated (nor-macusine B, voacorine, anhydrovobasinediol and an isomer of voacorine) and also a triterpene of the amyrin group.     

Iridoid and other constituents of Canthium subcordatum

The main constituent of the stem bark of Canthium subcordatum was found to be shanzhiside methyl ester, an iridoid recently described for two Mussaenda species; it is accompanied by the new iridoid shanzhisin methyl ester gentiobioside. No alkaloids were detected.     

季节和地理差异对天然黄檗小檗碱和药根碱含量的影响

用高效液相色谱法测定了黄檗根皮、茎皮、多年生枝皮、1年生枝和叶片中小檗碱和药根碱的含量,研究黄檗不同部位两种生物碱的季节和地理差异。结果表明:不同季节,天然黄檗各部位的小檗碱、药根碱含量均表现为:根皮茎皮多年生枝皮1年生枝叶片。小檗碱含量随着季节变化在各部位呈现夏季升高,到秋季下降的趋势。而药根碱在不同部位中的含量随着季节变化的规律不同。根皮、茎皮中的药根碱含量随着季节推移逐渐增多,在夏季升高不明显,而到秋季大量积累。多年生枝皮、1年生枝、叶片中的药根碱在3个季节表现则为先降后升。从纬度水平上看,不同地域间黄檗各部位的生物碱差异显著,在调查的40°—50°N范围内,黄檗两种生物碱的含量普遍在纬度低的地区较高,随着纬度增大先逐渐降低,到N44°左右达到最低值,到了高纬度地区略有回升。     

Alkaloid and lignan constituents of Cinnamosma madagascariensis

A new lignan glycoside, 5-methoxy-9-β-xylopyranosyl-(-)- isolariciresinol and two indole alkaloids have been characterised from the bark of Cinnamosma madagascariensis.     

New indolopyridoquinazoline alkaloids from Euxylophora paraënsis

Two new indolopyridoquinazoline alkaloids euxylophoricine C (V) and euxylophorine B (VI), were isolated from the bark of Euxylophora paraënsis Hub. Their structures were elucidated on the basis of spectroscopic as well as chemical properties and confirmed by synthesis.     

Dehydroisostrychnobiline,matopensine and other alkaloids from Strychnos kasengaensis

Eighteen alkaloids have been identified in the root bark, stem bark and leaves of Strychnos kasengaensis from Zaire, They are isoretulinal, retuline, desacetyl isoretuline, desacetyl retuline, dehydroisostrychnobiline, matopensine and its mono-N-oxide, nordihydrotoxiferine, isoretuline, N(1)-desacetyl 18-acetoxyisoretuline, Wieland-Gumlich aldehyde and diol, desacetyl isoretulinal, O-acetyl retuline, 16R-isositsirikine, O-acetyl isoretuline, 11-methoxy retuline and 11-methoxy isoretuline.     

New peptide alkaloids from Hovenia dulcis and H. tomentella

From the root bark of Hovenia dulcis Thunb. and H. tommentella (Makino) Nakai (Rhamnaceae), three peptide alkaloids, frangulanine, hovenins-A and -B have been isolated. Hovenin-A has been shown to be des-N-methylfrangulanine (II).     

Occurrence of N-cyano alkaloids in asian Strychnos species

The isolation of N-cyano-sec.-pseudostrychnine and N-cyano-sec.-pseudobrucine from the leaves of Strychnos wallichiana Steud. ex. DC. is reported. N-Cyano-sec.-pseudostrychnine and a N-cyano-sec.-pseudo-colubrine have been found among the alkaloids obtained from the stem bark of S. ignatii Berg.     

Phenolic dimers and an indole alkaloid from Campylospermum flavum (Ochnaceae)

From the leaves and stem bark of Campylospermum flavum (Ochnaceae), three compounds, namely 4?-O-methylagathisflavone, flavumchalcone, and flavumindole have been isolated together with 10 known compounds, including three flavonoids, two biflavonoids, two alkaloids, two nitrile glucosides, and glucopyranosyl-β-sistosterol. The structures of these compounds and their relative configurations were established by 1D and 2D NMR experiments. The methanolic crude extracts of leaves and stem bark of C. flavum and compounds displayed a significant cytotoxicity towards Artemia salina larvae.     

Alkaloids and olefinic acids from Cryptocarya amygdalina

From the bark of Cryptocarya amygdalina two new olefinic acids with a tetracyclo(4.3.0^2.4.0^3.7) non-8-enemoiety are reported. From the same source the benzylisoquinoline alkaloids orientaline and laudanidine are also reported.     

Polyavolinamide,an indolosesquiterpene alkaloid from Polyathia suaveolens

A new indolosesquiterpene alkaloid, polyavolinamide, has been identified in the stem of Polyathia suaveolens accompanied by the three previously isolated indolosesquiterpene alkaloids, polyavolensin, polyavolensinol, polyavolensinone, as well as an unidentified triterpene and an aporhine alkaloids. Polyavolinamide was also the major component of the root bark. Its structure was assigned on the basis of ¹¹H and ¹³C NMR, and mass spectrometry.     

Dimeric bisindole alkaloids from the stem bark of Strychnos nux-vomica L.

Strychnos nux-vomica L. (Loganiaceae) is famous for its monomeric alkaloid content, such as strychnine, a convulsant poison. The stem bark of the tree is traditionally used to treat intermittent fever in South East Asia. In various studies, it appeared that dimeric indolo-monoterpenic alkaloids possess a promising activity on Plasmodium falciparum. Three bisindolomonoterpenic alkaloids together with strychnochrysine, previously identified in the root bark of S. nux-vomica, were isolated from the stem bark. The structures of these compounds were established using NMR spectroscopy and mass spectrometry.Stereochemistry of the compounds was confirmed by molecular modelling. This then allowed the structural determination of strychnoflavine, a coloured bisindole alkaloid previously isolated from the root bark of the tree. Moreover, the conformational inversion in alkaloids possessing an ether bond in the strychnane moiety could be easily predicted by specific δ ¹³C NMR values.These longicaudatine-type alkaloids were found to display in vitro antiplasmodial activity against a chloroquine resistant strain and a chloroquine sensitive strain. The most interesting was strychnochrysine showing an IC₅₀ value at around 10 μM.     

Peptide alkaloids of Scutia buxifolia

From the bark extract of S. buxifolia, the known alkaloids scutianines B, C, D and E, and the new one, scutianine H, have been isolated. The structure of scutianine H, based mainly on its MS fragmentation and on the MIKES (mass-analysed ion kinetic energy spectrum) of the base ion peak, is suggested. From the ¹³C NMR spectral analysis of the diastereoisomeric scutianines D and E, information for the assignment of the stereochemistry of the β-hydroxyleucine unit in related alkaloids was also obtained.     

Alcaloides d'Araliopsis soyauxii. Isolement d'un nouvel alcaloide,l'Araliopsine

Six alkaloids have been isolated from root bark of Araliopsis soyauxii. Five are known, maculine, flindersiamine, skimmianine, (?) ribalinine, (+) isoplatydesmine and the sixth, araliopsine is new; its structure has been established as hydroxyisopropyldihydrofuro-2-quinolone. From the trunk bark four alkaloids have been isolated: flindersiamine, kokusaginine (?) ribalinine, (+) isoplatydesmine.     

Alkaloids of Hunteria zeylanica

Twenty alkaloids were isolated from the leaves and stem bark of Hunteria zeylanica, collected in Kenya. They were: 3-epi-dihydrocorymine 3-acetate, norisocorymine, corymine, 3-epi-dihydrocorymine 17-acetate, picralinal, picrinine, 3-epi-dihydrocorymine, isositsirikine, lanceomigine, geissoschizol, gentianine, kopsinine, eburnamine, norpleiomutine, pleiocarpamine, tubotaiwine, pleiomutinine, 19′-epi-pleiomutinine, yohimbol and 10-hydroxy-16-epi-affinine.