Alkaloids from the roots of Aconitum pseudo-laeve var. erectum

One new quinazoline (1) and two new norditerpenoid (2 and 3) alkaloids along with 10 known compounds were isolated from the roots of Aconitum pseudo-laeve var. erectum. The new alkaloids were assigned as 2-(2-methyl-4-oxo-4H-quinazoline-3-yl)benzoic acid methyl ester (1), 18-O-2-(2-methyl-4-oxo-4H-quinazoline-3-yl)benzoyllycoctonine (2), and 14-O-acetyl-8-O-methyl-18-O-2-(2-methyl-4-oxo-4H-quinazoline-3-yl)benzoylcammaconine (3). The structures of the new alkaloids were established by spectroscopic methods. This is the first report of the 2-(2-methyl-4-oxo-4H-quinazoline-3-yl)benzoyl ester group being found as an acyl substituent in norditerpenoid alkaloids (compounds 2 and 3).     

Stem bark alkaloids of Rauvolfia caffra

Thirty two alkaloids were isolated from the stem bark of Rauvolfia caffra and 28 were identified. The alkaloids represented corynane (3), strictamine (1), sarpagan (4), akuammicine (2), pleiocarpamine (1), indolenine (1), dihydroindole (6), peraksine (3), heteroyohimbine (2), hydroxyheteroyohimbine (2), oxindole (1), 2-acyl-indole (1), suaveoline (3) and yohimbine (2) types. The anhydronium base serpentine was detected but not isolated. The principal alkaloids were ajmaline and norajmaline (dihydroindoles), ajmalicinine and ajmalicine (heteroyohimbines), geissoschizol (E-seco indole) and pleiocarpamine and the heteroyohimbine derived alkaloids were predominantly normal configuration compounds. The biosynthetic and ethnopharmacological significance of the alkaloids is discussed.     

色氨酸及其衍生物对海南粗榧悬浮细胞合成三尖杉酯类碱的影响

目的研究L-色氨酸及其衍生物5-甲基-DL-色氨酸(5-MT)对海南粗榧悬浮细胞生长及三尖杉酯类碱合成的影响。方法在细胞培养第15天,向海南粗榧悬浮培养物中添加一定量的L-色氨酸或5-MT,测定细胞生长、产物量以及代谢途径中关键酶的活力。结果 L-色氨酸与5-MT都能促进三尖杉酯类碱的合成。添加5 mg/L 5-MT时,产物量最高(2.944 mg/L);添加10 mg/L L-色氨酸和5 mg/L 5-MT后,三尖杉酯类碱产量分别是对照(1.343 mg/L)的1.947、2.192倍;而悬浮细胞生物量分别比对照(2.406 g/L)降低了9.35%、18.04%。同时,3-脱氧-D-阿拉伯庚酮糖-7-磷酸合成酶活性分别比对照(0.67 U/mg)降低了12.4%、5.57%;苯丙氨酸解氨酶活性分别比对照(78.21 U/mg)增加了37.72%、28.02%;酚类物质积累比对照(0.36mg/mL)增加了19.14%、9.61%。结论 L-色氨酸及其衍生物5-MT能抑制代谢支路,促进代谢流向产物三尖杉酯类碱的方向。     

Terpenoid indole alkaloids from Winchia calophylla

Three new indole alkaloids, N(4)-demethyl-12-methoxyalstogustine (1), 17-carboxyl-N(4)-methylechitamidine chloride (2), and 17-carboxyl-12-methoxy-N(4)-methylechitamidine chloride (3), along with 15 known alkaloids, were isolated from the ethanolic extract of the stem bark of Winchia calophylla. The structures of 1-3 were elucidated on the basis of spectroscopic means and chemical methods. The determination of relative configurations at C-19 and C-20 for 1-3 was aided by 13C NMR spectroscopic data. The absolute configurations of alkaloids 1-3 were determined by direct comparison of their CD spectra with those of known alkaloids. All the alkaloids were tested in cytotoxic assays against P-388 and A-549 tumor cell lines, and only two of them showed weak activity against the A-549 cell line.     

Isolation of gelsedine-type indole alkaloids from Gelsemium elegans and evaluation of the cytotoxic activity of gelsemium alkaloids for A431 epidermoid carcinoma cells

Four new gelsedine-type indole alkaloids (1-4) were isolated from the leaves of Gelsemium elegans, together with 11 known alkaloids. The structures were determined as 14-acetoxygelsenicine (1), 14-acetoxy-15-hydroxygelsenicine (2), 14-hydroxy-19-oxogelsenicine (3), and 14-acetoxygelselegine (4), respectively, by spectroscopic analysis. The cytotoxic effects of 14 Gelsemium alkaloids including two new compounds (1, 2) were evaluated using the A431 human epidermoid carcinoma cell line. Of these, the gelsedine-type alkaloids 14-acetoxy15-hydroxygelsenicine (2) [corrected] 14,15-dihydroxygelsenicine (5), gelsedine (7), and gelsemicine (8) showed potent cytotoxic effects.     

Alkaloids from Gelsemium elegans

Three new alkaloids, gelsebanine (1), 14alpha-hydroxyelegansamine (2), and 14alpha-hydroxygelsamydine (3), and a new extraction artifact , gelsebamine (4), together with 12 known alkaloids, were isolated from the stems and leaves of Gelsemium elegans. The structures of 1-4 were determined by spectroscopic methods, especially 2D NMR techniques. Compounds 1-4 were evaluated for cytotoxic activity against four tumor cell lines, and gelsebamine (4) selectively inhibited the A-549 human lung adenocarcinoma cell line.     

New cytotoxic alkaloids from the wood of Vepris punctata from the Madagascar rainforest

Bioassay-guided fractionation of a CH(2)Cl(2)/MeOH extract of the wood of Vepris punctata resulted in the isolation of three new furoquinoline alkaloids, 5-methoxymaculine (1), 5,8-dimethoxymaculine (2), and 4,5,6,7,8-pentamethoxyfuroquinoline (3), in addition to the four known alkaloids flindersiamine (4), kokusaginine (5), maculine (6), and skimmianine (7). The structures of the new alkaloids 1-3 were established on the basis of extensive 1D and 2D NMR spectroscopic data interpretation. All the isolated compounds were tested against the A2780 human ovarian cancer cell line, and all seven alkaloids showed weak cytotoxic activity.     

海绵Ircinia sp.中几种含溴生物碱的分离与鉴定

目的:研究海绵Ircinia sp.中生物碱成分。方法:通过多种色谱手段,对海绵Ircinia sp.中的生物碱成分进行分离纯化,根据波谱数据和理化性质确定化合物的结构。结果:从海绵Ircinia sp.中共分离得到5个含溴生物碱,分别鉴定为:fistularin-1(1)、fistularin-3(2)、aerothionin(3)、11-hydroxyaerothionin(4)、suberamolline A(5)。结论:以上5个生物碱均为首次从中国南海海绵Ircinia sp.中分离得到。     

New alkaloids of the sarpagine group from Rauvolfia serpentina hairy root culture

Three new monoterpenoid indole alkaloids, 19(S),20(R)-dihydroperaksine (1), 19(S),20(R)-dihydroperaksine-17-al (2), and 10-hydroxy-19(S),20(R)-dihydroperaksine (3), along with 16 known alkaloids 4-19 were isolated from hairy root culture of Rauvolfia serpentina, and their structures were elucidated by 1D and 2D NMR analyses. Taking into account the stereochemistry of the new alkaloids and results of preliminary enzymatical studies, the putative biosynthetical relationships between the novel alkaloids are discussed.     

Antimalarial, cytotoxic, and antifungal alkaloids from Duguetia hadrantha

Bioassay-guided isolation of Duguetia hadrantha yielded two new 4,5-dioxo-1-azaaporphinoids, hadranthine A (1) and hadranthine B (2), together with the known alkaloids imbiline-1 (3), sampangine (4), and 3-methoxysampangine (5), whose structures were determined primarily from 2D-NMR 1H-13C HMBC, and 1H-15N HMBC experiments. This is the first report of the co-occurrence of the copyrine alkaloids 4 and 5, as well as the first report of either copyrine or imbiline type alkaloids from a Duguetia species. Compounds 1, 4, and 5 demonstrated in vitro antimalarial activity against Plasmodium falciparum (W-2 clone), while 2 was inactive. Instead, 2 showed in vitro cytotoxicity to selected human cancer cell lines (IC50 = 3-6 microg/mL against SK-MEL, KB, BT-549, and SK-OV-3), and 4 was also cytotoxic to human malignant melanoma (IC50 = 0.37 microg/mL). Sampangine (4) also inhibited cell aggregation with a MIC value of <0.15 microg/mL, while 3-methoxysampangine (5) was only weakly active.     

Diterpenoid alkaloids from the roots of Delphinium scabriflorum

Chemical investigation of the CHCl(3) extracts from the roots of Delphinium scabriflorum has resulted in the isolation of a new diterpenoid alkaloid, 13-(2-methylbutyryl)azitine (1), along with 11 known alkaloids, delbine (2), 14-deacetyl-14-isobutyrylajadine (3), methyllycaconitine (4), 14-deacetylnudicauline (5), delectinine (6), deltatsine (7), dictysine (8), geyerline (9), ajacine (10), lycoctonine (11), and delcosine (12). The structure of 1 was determined by spectroscopic data interpretation. Complete NMR data for alkaloids 2-8 are presented. Some earlier (13)C NMR assignments made for alkaloids 4-7 were revised.     

Hetisine-type diterpenoid alkaloids from the Bhutanese medicinal plant Aconitum orochryseum

Investigation of Aconitum orochryseum, a Bhutanese traditional medicine ("gSo-ba Rig-pa") plant locally known as "Bong-kar", resulted in the isolation of three new hetisine-type diterpenoid alkaloids, named orochrine (1), 2-O-acetylorochrine (2), and 2-O-acetyl-7alpha-hydroxyorochrine (3), together with the previously reported alkaloids atisinium chloride (4) and virescenine (5). The structures of the new alkaloids were elucidated by spectroscopic data analysis.     

New tropane alkaloids from Erythroxylum moonii

Four new tropane alkaloids were isolated from the leaves of Erythroxylum moonii and identified as 3 alpha-isobutyryloxy-7 beta-hydroxynortropane (1), 3 alpha-hydroxy-7 beta-phenylacetoxynortropane (2), 3 alpha-cis-cinnamoyloxytropane (3), and 3 alpha-hydroxy-6 beta-(3'-hydroxy-2'-methyl-3'-phenylpropionyloxy)-7 beta-hydroxytropane (4). Other alkaloids isolated for the first time from E. moonii were 3 alpha-benzoyloxytropane, 3 alpha-phenylacetoxytropane, 3 alpha-trans-cinnamoyloxytropane, and 3 alpha-phenylacetoxy-6 beta,7 beta-dihydroxynortropane. The structures of compounds 1-4 were elucidated by spectroscopic methods.     

Bioactive acridone alkaloids from Swinglea glutinosa

A new prenylated acridone alkaloid, 1,3,5-trihydroxy-2,8-bis(3-methylbut-2-enyl)-10-methyl-9-acridone (1), was isolated from the stembark of Swinglea glutinosa, along with three known acridone alkaloids, 5-hydroxynoracronycine (2), 1,3,5-trihydroxy-4-methoxy-2-(3-methylbut-2-enyl)-10-methyl-9-acridone (3), and 1,3,5-trihydroxy-4-methoxy-10-methylacridone (4). The isolated alkaloids were assessed in vitro against chloroquine-sensitive and -resistant Plasmodium falciparum strains and for cytotoxicity using HeLa cells.     

Monoterpenoid indole alkaloids from Gardneria ovata

Eight new monoterpenoid indole alkaloids, gardfloramine-9-O-β-D-glucopyranoside (1), 19(E)-18-demethoxygardfloramine-N(4)-oxide (2), gardfloramine-N(4)-oxide (3), 18-demethylgardfloramine (4), 19(E)-9,18-didemethoxygardneramine (5), 19(E)-11-methoxy-9,18-didemethoxygardneramine (6), 9-demethoxy-18-demethylgardneramine (7), and minfiensine-N(4)-oxide (8), along with six known alkaloids, were isolated from Gardneria ovata. The structures of the new alkaloids were established by means of spectroscopic methods. None of the compounds were cytotoxic to five human cancer cell lines.     

Alkaloids from Delphinium staphisagria

Three new diterpenoid alkaloids, isoazitine (1), 19-oxodihydroatisine (2), and 22-O-acetyl-19-oxodihydroatisine (3), and eight known alkaloids-azitine (4), dihydroatisine (5), delphinine, neoline, bullatine C (14-acetylneoline), chasmanine, 14-acetylchasmanine, and the quaternary base atisinium chloride (7)-were isolated from the aerial parts of Delphinium staphisagria. Structures of the new alkaloids were established mainly by 1D and 2D NMR spectroscopy, including (1)H COSY, HMQC, HMBC, and ROESY. The (1)H and (13)C NMR data for alkaloids 4 and 5 are also reported.     

Alkaloids from the roots of Stemona saxorum

Five new Stemona alkaloids, cochinchistemoninone (1), stemokerrin-N-oxide (2), oxystemokerrilactone (3), saxorumamide (4a), and isosaxorumamide (4b), as well as 12 known compounds, were isolated from the roots of Vietnamese Stemona saxorum. The structures of these alkaloids were characterized on the basis of spectroscopic methods.     

Biologically active aspidofractinine alkaloids from Kopsia singapurensis

Ten new indole alkaloids of the aspidofractinine type, in addition to several recently reported indole alkaloids and 20 other known alkaloids, were obtained from the leaf and stem-bark extract of the Malayan Kopsia singapurensis, viz., kopsimalines A-E (1-5), kopsinicine (6), kopsofinone (7), and kopsiloscines H-J (8-10). The structures of these alkaloids were determined using NMR and MS analysis. Kopsimalines A (1), B (2), C (3), D (4), and E (5) and kopsiloscine J (10) were found to reverse multidrug-resistance in vincristine-resistant KB cells, with 1 showing the highest potency.     

Two Alangium alkaloids from Alangium lamarckii

Two new Alangium alkaloids, 1',2'-dehydrotubulosine (1) and alangine (2), were isolated from the dried fruits of Alangium lamarckii along with tubulosine (3), isotubulosine (4), deoxytubulosine, cephaeline, isocephaeline, psychotrine, neocephaeline, 10-O-demethylcephaeline, 2'-N-(1"-deoxy-1" -beta-D-fructopyranosyl)cephaeline, protoemetine, protoemetinol, salsoline, and alangiside. The structures of the new alkaloids (1 and 2) were determined by spectroscopic and chemical means.     

Arenosclerins A-C and haliclonacyclamine E, new tetracyclic alkaloids from a Brazilian endemic Haplosclerid sponge Arenosclera brasiliensis

Arenosclerins A (2), B (3), and C (4), as well as haliclonacyclamine E (1), are new tetracyclic alkylpiperidine alkaloids isolated from a new species of marine sponge belonging to the order Haplosclerida, Arenosclera brasiliensis, a species endemic to the southeastern Brazilian coast. The alkaloids were isolated as their hydrochloride salts and identified by analysis of spectroscopic data. Data obtained from (1)H-(1)H COSY, HMBC, and HSQC-TOCSY NMR experiments allowed complete assignment of the (1)H and (13)C resonances, and analysis of the NOESY and ROESY spectra showed that the only differences between 2, 3, and 4 were the relative stereochemistries of the bispiperidine ring system. Arenosclerins A-C are the first haliclonacyclamine/halicyclamine-related alkaloids with a hydroxy group in the bridging alkyl chain.