Yuzurimine-type alkaloids from Daphniphyllum yunnanense

Five new yuzurimine-type alkaloids, yunnandaphnines A-E (2-6), together with two known analogues, macrodaphniphyllamine (1) and calycinine A (7), have been isolated from the leaves and twigs of Daphniphyllum yunnanense. The structures of the new alkaloids were elucidated by spectroscopic methods. Yunnandaphnine E (6) is a novel heptacyclic yuzurimine-type alkaloid with an oxazine ring.     

New alkaloids from Pandanus amaryllifolius

Three new alkaloids, the two pyrrolidine type alkaloids (1 and 2) and 6E-pandanamine (3), together with five known alkaloids (4-8), were isolated from the leaves of Pandanus amaryllifolius collected in West Java, Indonesia. All the new alkaloids have two alpha-methyl alpha,beta-unsaturated gamma-lactone moieties, while compound 2 also has an additional seven-membered ring, which has not been encountered before in Pandanus alkaloids. Two different extraction methods, namely, a solvent partitioning extraction and acid-base treatment, were tested, giving secondary and tertiary amines, respectively. Spectroscopic and chemical studies showed that the tertiary amines isolated from the acid-base treatment were artifacts formed during the extraction process. This finding suggests that the use of conventional acid-base treatment in isolating Pandanus alkaloids should be reviewed since it can introduce artifacts.     

New alkaloids from Daphniphyllum calycinum

Four new alkaloids, 17-hydroxyhomodaphniphyllic acid (1), daphcalycinosidine C (2, a new iridoid alkaloid), yuzurimine E (3), and yuzurimic acid B (4), were isolated from the seeds of Daphniphyllum calycinum. The structures of these Daphniphyllum alkaloids were determined by spectroscopic analysis including mass spectrometry and 2D NMR.     

Quinolizidine alkaloids from Sophora alopecuroides

A new matrine-type alkaloid, 7alpha-hydroxysophoramine (1), was isolated from the aerial parts of Sophora alopecuroides together with eight known alkaloids, 12beta-hydroxysophocarpine (2), sophoramine (3), 14beta-hydroxymatrine, matrine, sophoridine, sophocarpine, adenocarpine, and baptifoline. The structures of compounds 1-3 were confirmed through single-crystal X-ray diffraction analysis.     

Cyclopeptide alkaloids from Paliurus ramossisimus

Seven zizyphine A-type cyclopeptide alkaloids were isolated from the roots of Paliurus ramossisimus by the combination of centrifugal partition chromatography and conventional separation methods. The novel structures of paliurines A-F (1-6) were characterized and established on the basis of MS and elaborate NMR spectral analyses. Terminal dipeptide stereochemistry was confirmed by correlation with the synthetic dipeptides via comparison of their (13)C NMR data.     

Pyrrolizidine alkaloids from Heliotropium rotundifolium

Heliotropium rotundifolium was shown to contain, in addition to the previously isolated europine [1], three other alkaloids: heliotrine [2], lasiocarpine [3], and a new alkaloid identified as 5'-acetyleuropine [4]. The alkaloids were isolated by dccc and the structures established by spectroscopic means (1H and 1H- 13CHETCOR nmr and ms), physical properties (melting points and/or optical rotations), comparison with authentic samples, or by semi-synthesis.     

Fawcettimine-related alkaloids from Lycopodium serratum

Five new Lycopodium alkaloids (1-5) having the fawcettimine skeleton were isolated from Lycopodium serratum. The structures of the alkaloids were elucidated on the basis of spectroscopic analysis. Some alkaloids isolated in this and previous studies (1, 2, 5, and 10) were assayed for acetylcholine esterase (AChE) inhibitory activity.     

Indole alkaloids from Geissospermum reticulatum

Ten indole alkaloids were isolated from Geissospermum reticulatum, seven (1-7) from the leaves and three (8-10) from the bark. Seven were aspidospermatan-type alkaloids (1-3, 5-9), including four (5-8) with a 1-oxa-3-cyclopentene group in their molecule, which we named geissospermidine subtype. Compounds 1-3, 5-8, and 10 had not been reported previously as natural products, while 4 and 9 were the known alkaloids O-demethylaspidospermine and flavopereirine. Their structures were determined by spectroscopic techniques including 1D and 2D NMR experiments (COSY, NOESY, HSQC, HMBC). Additionally, X-ray crystallographic analyses of 1, 2, and 6 were performed. Antiparasitic activities of the ethanolic and alkaloidal extracts and of the pure alkaloids were tested against Trypanosoma cruzi and Leishmania infantum. In general, the extracts exhibited selective action and were more active against Leishmania than against Trypanosoma. Alkaloid 4 was also very active against L. infantum.     

Antiproliferative alkaloids from Crinum zeylanicum

Crinum zeylanicum is used in folk medicine as a rubefacient in rheumatism, a treatment for malaria or as a poison. Complex alkaloid profiles in C. zeylanicum plant organs were revealed by GC‐MS analysis, including several bioactive compounds. Crinine, lycorine, 11‐O‐acetoxyambelline, ambelline, 6‐hydroxybuphanidrine and 6‐ethoxybuphanidrine (an artefact of the isolation procedure) were isolated. Crinine, 6‐hydroxybuphanidrine and 6‐ethoxybuphanidrine showed antiproliferative effects against human tumor cell lines, crinine being the most active (IC₅₀ 14.04 μm against HL‐60/Dox). The latter compound induced apoptosis in a dose‐dependent manner in HL‐60 and MDA‐MB‐231 cell lines. Structure‐activity relationships in the studied molecules indicated that the hydrogenation of the double bond at C1‐C2 leads to a loss of activity, whereas substitutions at C6, C8 and C11 affect their cytotoxicity. Copyright © 2011 John Wiley & Sons, Ltd.     

Antiparasitic alkaloids from Psychotria klugii

Psychotria klugii yielded two new benzoquinolizidine alkaloids, klugine (1) and 7'-O-demethylisocephaeline (2), together with the previously known cephaeline (3), isocephaeline (4), and 7-O-methylipecoside (5). The structures and stereochemistry of 1 and 2 were determined by 1D and 2D NMR data and circular dichroism experiments. Cephaeline (3) demonstrated potent in vitro antileishmanial activity against Leishmania donavani (IC(50) 0.03 microg/mL) and was >20- and >5-fold more potent than pentamidine and amphotericin B, respectively, while klugine (1) (IC(50) 0.40 microg/mL) and isocephaeline (4) (IC(50) 0.45 microg/mL) were <13- and <15-fold less potent than 3. In addition, emetine (6) (IC(50) 0.03 microg/mL) was found to be as equally potent as 3, but was >12-fold more toxic than 3 against VERO cells (IC(50) 0.42 vs 5.3 microg/mL). Alkaloids 1 and 3 exhibited potent antimalarial activity against Plasmodium falciparum clones W2 and D6 (IC(50) 27.7-46.3 ng/mL). Compound 3 was cytotoxic to SK-MEL, KB, BT-549, and SK-OV-3 human cancer cells, while 1 was inactive.     

海南狗牙花中的吲哚类生物碱化学成分研究

目的 对海南狗牙花中的吲哚类生物碱进行分离鉴定.方法 采用硅胶、Sephadex LH-20等柱色谱方法进行分离,NMR等波谱学方法进行结构鉴定.结果 从海南狗牙花中分离鉴定了7个吲哚类生物碱,分别为:海南狗牙花素(hainanervatasine, I)、海南狗牙花新(hainanervatacine, Ⅰ)、老刺木碱(vobasine, Ⅱ)、冠狗牙花定(coronaridine, Ⅳ)、3-羟基冠狗牙花定(3-hydroxyl coronaridine, Ⅴ)、3-(2-羰基-丙基)冠狗牙花碱[3-(2-oxopropyl) coronaridine, Ⅵ]、山辣椒胺(tabernamine, Ⅶ).结论 化合物Ⅰ、Ⅱ为新化合物,分别命名为海南狗牙花素(Ⅰ)、海南狗牙花新(Ⅱ),化合物Ⅳ、Ⅵ为首次从该植物中分离得到.     

Imidazole alkaloids from Lepidium meyenii

Two new imidazole alkaloids (lepidiline A and lepidiline B) have been isolated from a root extract of Lepidium meyenii with the common name Maca and identified as 1,3-dibenzyl-4,5-dimethylimidazolium chloride (1) and 1,3-dibenzyl-2,4,5-trimethylimidazolium chloride (2), respectively. The structures of these two new compounds were determined by spectroscopic methods, as well as single-crystal X-ray diffraction performed on compound 1.     

New alkaloids from Annona purpurea

Three new alkaloids, promucosine (1), romucosine F (2), and romucosine G (3), along with 28 known compounds, were isolated from the MeOH extract of stems of Annona purpurea. The structures of 1-3 were determined on the basis of spectral data and chemical evidence.     

New alkaloids from Cephalotaxus fortunei

Four new cephalotaxus alkaloids, cephalotaxine alpha-N-oxide (1), cephalotaxine beta-N-oxide (2), 11-beta-hydroxycephalotaxine beta-N-oxide (3), and isocephalotaxine (4), were isolated, together with several known alkaloids from an EtOAc extract of the fruits of Cephalotaxus fortunei. The structures were determined by spectral analysis including mass spectrometry and 2D NMR. Compounds 1, 2, 3, and 4 displayed cytotoxicity against nasopharynx KB cells with IC50 values of 30, 14, 31, and 15 micro g/mL, respectively.     

Indole alkaloids from Cephalanceropsis gracilis

Purification of CHCl3 and EtOAc solubles of the MeOH extract of Cephalanceropsis gracilis afforded seven new indole alkaloids, cephalinones A (1), B (2), C (3), and D (4) and cephalandoles A (5), B (6), and C (7), besides eight known compounds. The structures of the new compounds were determined by spectroscopic analysis. All 15 indole alkaloids were evaluated for their cytotoxic effects on MCF-7, NCI-H460, and SF-268 cell lines by the MTT method. Only cephalinone-F (6) showed significant cytotoxicity.     

Norditerpenoid alkaloids from Delphinium nordhagenii

Three new norditerpenoid alkaloids, nordhagenine A (1), nordhagenine B (2), and nordhagenine C (3), along with a known alkaloid, lycoctonine, were isolated from the aerial parts of Delphinium nordhagenii. The structures of the new compounds 1 and 2 were also deduced on the basis of single-crystal X-ray diffraction studies.     

Monoterpene indole alkaloids from Palicourea crocea

Two new monoterpene indole alkaloids, named croceaines A (1) and B (2), were isolated from the leaves of Palicourea crocea. The structures of 1 and 2 were elucidated by means of spectroscopic methods.     

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.     

New diketopiperazine alkaloids from Penicillium fellutanum

Four new diketopiperazine alkaloids (1-4) were isolated from cultures of Penicillium fellutanum, and their structures were determined by MS and NMR measurements.