Two pairs of enantiomeric neolignans from Lobelia chinensis

A pair of new enantiomeric neolignans, ethyl 3-[(2R,3S)-2-(4-hydroxy-3-methoxyphenyl)-3-(hydroxymethyl)-7-methoxy-2,3-dihydro-1-benzofuran-5-yl] propanoate (+) (1) and ethyl 3-[(2S,3R)-2-(4-hydroxy-3-methoxyphenyl)-3-(hydroxymethyl)-7-methoxy-2,3-dihydro-1-benzofuran-5-yl] propanoate (-) (1), together with a pair of known enantiomeric neolignans (+) (2) and (-) (2), as well as five known lignans (3-7) were isolated from the ethanol extract of Lobelia chinensis. Their structures were elucidated on the basis of extensive spectroscopic analyses, including 1D and 2D NMR, HR-ESI-MS and CD spectra.     

Neolamarckines A and B, new indole alkaloids from Neolamarckia cadamba

Two new indole alkaloids, neolamarckines A and B (1, 2) were isolated from the leaves of Neolamarckia cadamba (Rubiaceae). Structural elucidation of 1 and 2 was performed by combination of 2D-NMR and circular dichroism (CD) spectra, and chemical correlations. Neolamarckine A (1) showed inhibition of inducible nitric oxide synthase (iNOS) dose dependently.     

Schulzeines A-C, new alpha-glucosidase inhibitors from the marine sponge Penares schulzei

Three new alpha-glucosidase inhibitors, schulzeines A-C (1-3), were isolated from the marine sponge Penares schulzei. Their structures were elucidated by spectral analysis and chemical degradations to be the isoquinoline alkaloids, encompassing two amino acids, and C(28) fatty acid, the last of which was sulfated. Absolute stereochemistry of schulzeines was determined by application of the modified Mosher analysis to fragments obtained by chemical degradation. Schulzeines A-C inhibit alpha-glucosidase with IC(50) values of 48-170 nM.     

Two new alkaloids from Miliusa cuneata

Two new isoquinoline alkaloids, 2,10-dimethoxy-3,11-dihydroxy-5,6-dihydroprotoberberine (1) and 1,9-dihydroxy-2,11 -dimethoxy-4,5-dihydro-7-oxoaporphine (2), together with thirteen known alkaloids, were isolated from the ethanolic extracts of the stem and leaves of Miliusa cuneata (Graib). Their structures were elucidated predominantly by spectral evidence.     

Two new alkaloids from Capparis himalayensis

Two new alkaloids, Capparin A (1) and B (2), along with seven known compounds 6-methoxyindoline-2,3-dione (3), wogonin (4), oroxylin A (5), kaempferol (6), apigenin (7), quercetin (8) and luteolin (9), were isolated from the whole plant of Capparis himalayensis. Their structures have been established on the basis of spectral methods and the structure of 1 was confirmed by X-ray crystallographic analysis.     

Kuroshines A and B,new alkaloids from Zoanthus kuroshio

A chemical investigation of Zoanthus kuroshio has yielded two new alkaloids, kuroshines A (1) and B (2). The compounds possess a densely functionalized ring system on the basis of the zoanthamine frames. The structures of 1 and 2 were elucidated through interpretation of spectroscopic methods, especially 2D NMR techniques (COSY, HMQC, HMBC, and ROESY). The absolute stereochemistry of 1 was further confirmed by an X-ray single crystallographic analysis using a mirror Cu-Kα radiation.     

Hyrtioseragamines A and B, new alkaloids from the sponge Hyrtios species

Two novel alkaloids with a furo[2,3-b]pyrazin-2(1H)-one moiety and a guanidino group, hyrtioseragamines A (1) and B (2), have been isolated from an Okinawan marine sponge Hyrtios species. The structures of 1 and 2 were elucidated on the basis of spectroscopic data and chemical conversions. Compounds 1 and 2 are the first natural products possessing a furo[2,3-b]pyrazine-related moiety.     

Isatinones A and B, new antifungal oxindole alkaloids from Isatis costata

Two new oxindole alkaloids isatinone A (1) and B (2) have been isolated from Isatis costata, along with the known trisindoline. Their structures have been assigned on the basis of spectroscopic techniques and chemical studies. Both new compounds showed significant antifungal activity.     

Paxiphyllines A and B, new alkaloids from Daphniphyllum paxianum

Two new Daphniphyllum alkaloids with daphnicyclidin-type skeleton, paxiphyllines A (1) and B (2) were isolated from the twigs and the leaves of Daphniphyllum paxianum. Paxiphylline A (1) has an unprecedented additional carbon from a biogenetic perspective. The structures and relative configurations were elucidated on the basis of spectroscopic data.     

Phenolic glycosides and pyrrolidine alkaloids from Codonopsis tangshen

Chemical examination of the n-butanol extract of the root of Codonopsis tangshen led to the isolation of four new compounds named codonosides A (1) and B (2) and codonopyrrolidiums A (3) and B (4), with seven known compounds [(Z)-2-(beta-glucopyranosyloxy)-3-phenylpropenoic acid (5), lobetyolin (6), lobetyol (7), luteolin (8), friedelin (9), 5,6,9-trihydroxy-octadec-7-enoic acid (10), and adenosine (11)]. Based on spectroscopic evidence, the structures of codonosides A (1) and B (2) were established as phenolic glycosides, and those of codonopyrrolidiums A (3) and B (4) as pyrrolidines. The relative configuration of 3 was determined by X-ray crystallographic analysis.     

Complanadine B, obscurumines A and B, new alkaloids from two species of Lycopodium

A new dimer of C₁₆N₂ type alkaloid, complanadine B (1), and two new C₁₆N type alkaloids, obscurumines A (2) and B (3), have been isolated from the club moss Lycopodium complanatum and L. obscurum, respectively. The structures and stereochemistry of 1-3 were elucidated by combination of 2D NMR spectra and chemical transformation. Complanadine A (4) isolated together with 1 induced secretion of neurotrophic factors from human astrocytoma cells.     

Pseuduvarines A and B, two new cytotoxic dioxoaporphine alkaloids from Pseuduvaria rugosa

Pseuduvarines A (1) and B (2), two new dioxoaporphine alkaloids with an amino moiety, were isolated from the stem bark of Pseuduvaria rugosa and their structures were elucidated by combination of 2D-NMR spectroscopic analysis. Pseuduvarines A (1) and B (2) showed cytotoxicity against MCF7, HepG2, and HL-60 (1: IC??, 0.9, 21.7, and >50.0 μM, respectively, 2: IC?? >50.0, 15.7, and 12.4 μM, respectively).     

Wrightiamines A and B,two new cytotoxic pregnane alkaloids from Wrightia javanica

Two new pregnane alkaloids, wrightiamines A (1) and B (2), were isolated from the extract of the tropical Apocynaceous plant Wrightia javanica collected in Thailand, and their structures were elucidated by spectral data. Wrightiamine B (2) was preparaed from 3beta-hydroxy-5alpha-pregnan-20-one to establish the configuration of the C-20 position as S. Wrightiamine A (1) exhibited cytotoxic activity against vincristine-resistant murine leukemia P388 cells.     

Flueggines A and B, two new dimeric indolizidine alkaloids from Flueggea virosa

Two unprecedented C,C-linked dimeric indolizidine alkaloids, flueggines A (1) and B (2), were isolated from the twigs and leaves of Flueggea virosa. The structures and absolute configurations were elucidated by means of NMR, single-crystal X-ray diffraction, and CD analyses. Compound 1 is the first example of Securinega alkaloids bearing an isoxazolidine ring, the plausible biogenetic pathway of which is also proposed. Compound 2 exhibited growth inhibitory activity against MCF-7 and MDA-MB-231 human breast cancer cells.     

Mekongenines A and B, two new alkaloids from Bousigonia mekongensis

Mekongenine A (1) possessing an unprecedented structure constituted from the union of a rare 2,7-seco eburnamine half and an aspidospermine alkaloid, together with a new bisindole alkaloid, mekongenine B (2), consisting of an eburnamine-aspidospermine type skeleton, was isolated from Bousigonia mekongensis. Their structures were elucidated by means of spectroscopic methods and those of 2 were further confirmed by X-ray diffraction. The absolute configurations of 1 and 2 were determined by comparison of quantum chemical TDDFT calculated and experimental ECD spectra. Mekongenines A (1) and B (2) exhibited cell growth inhibitory activities against various human cancer cell lines.     

Studies on the constituents of Broussonetia species. VII. Four new pyrrolidine alkaloids, broussonetines M, O, P, and Q, as inhibitors of glycosidase, from Broussonetia kazinoki SIEB

Four new pyrrolidine alkaloids, broussonetines M, O, P, and Q, were isolated from the branches of Broussonetia kazinoki SIEB, (Moraceae). Broussonetines M, O, P, and Q were formulated as (2R,3R,4R,5R)-2-hydroxymethyl-3,4-dihydroxy-5-[(10S)-10,13-dihydroxy-tri decyl]pyrrolidine (1), (2R,3R,4R,5R)-2-hydroxymethyl-3,4-dihydroxy-5-[(E)9-oxo-13-hydroxy-3- tridecenyl]pyrrolidine (2), (2R,3R,4R,5R)-2-hydroxymethyl-3,4-dihydroxy-5-[(E)10-oxo-13-hydroxy-3-++ +tridecenyl]pyrrolidine (3), and (2R,3S,4R,5R)-2-hydroxymethyl-3-hydroxy-4-(beta-D-glucopyranosyloxy++ +)-5-[10-oxo-13-(beta-D-glucopyranosyloxy)tridecyl]pyrrolidine (4) respectively, by spectroscopic and chemical methods. 1-4 inhibited beta-glucosidase, beta-galactosidase and beta-mannosidase.     

Two new alkaloids from Melodinus hemsleyanus Diels

Two new monoterpenoid indole alkaloids, named 14,15-dihydro-14β,15β-epoxy-10-hydroxyscandine (1) and 15α-hydroxy-meloscandonine (2), together with 12 known compounds, were isolated from the aerial parts of Melodinus hemsleyanus Diels. The structures of 1 and 2 were elucidated on the bases of 1D and 2D NMR spectra and MS. Two new compounds were evaluated for their PTP1B and Drak2 inhibitory effects, and inactivity.     

Two new alkaloids from Narcissus serotinus L

The Amaryllidaceae family is well known for the presence of an exclusive group of alkaloids with a wide range of biological activities. Narcissus serotinus L. is a plant belonging to this family and its geographical distribution is mainly located along the Mediterranean coast. In the present work, specimens collected near Casablanca (Morocco) were used to study the alkaloid content of this species. Starting with 350 g of the whole plant we used standard extraction and purification procedures to obtain fractions and compounds for GC-MS and NMR analysis. As well as five known alkaloids, we isolated two new compounds: 1-O-(3′-acetoxybutanoyl)lycorine and narseronine. The latter has been previously published, but with an erroneous structure.     

Two new pyrrolizidine alkaloids from Senecio nemorensis

Two new compounds, including petasinoside A and chloridate-[N-chloromethyl-hectorine], were isolated from Senecio nemorensis. The structures of these compounds were elucidated by spectroscopic methods including 1D and 2D NMR experiments.