Oryzamutaic acids H-J, new alkaloids from an Oryza sativa mutant with yellow endosperm

Three new nitrogen-containing heterocyclic alkaloids, oryzamutaic acids H-J (1-3), were isolated from the endosperm (polished rice) of an Oryza sativa mutant. The structures and relative stereochemistries of 1-3 were elucidated on the basis of spectroscopic analyses. The presence of three carbons, each bound to a carboxyl group and a nitrogen atom in the structure of 1, suggests that oryzamutaic acids H-J (1-3) are generated from three molecules of a single amino acid.     

Oryzamutaic acid A, a novel yellow pigment from an Oryza sativa mutant with yellow endosperm

Oryzamutaic acid A, a novel yellow pigment, was isolated from the endosperm of an Oryza sativa mutant. The structure and absolute configuration of oryzamutaic acid A were elucidated on the basis of spectroscopic analysis, single-crystal X-ray diffraction analysis, and biogenetic reason. Oryzamutaic acid A might be biogenetically derived from four l-amino acids because it contains three amino acid groups and one amine group.     

Daphniglaucins D-H, J, and K, new alkaloids from Daphniphyllum glaucescens

Five new fused-hexacyclic alkaloids, daphniglaucins D (1), E (2), F (3), G (4), and H (5), and two new yuzurimine-type alkaloids, daphniglaucins J (6) and K (7), have been isolated from the leaves of Daphniphyllum glaucescens, and the structures and relative stereochemistry were elucidated on the basis of spectroscopic data and chemical means.     

Hesseltins B-G, novel meroterpenoids from a new Penicillium species

Six new meroterpenoid compounds, hesseltins B-G, were isolated from Penicillium species along with the previously described hesseltin A. A further 14 compounds, which turned out to be photoisomers, were detected during purification and were subsequently isolated. The structures of these analogues were elucidated by comparison of their NMR spectral data with that of hesseltin A. None of the new hesseltins showed antiviral activity in a Herpes simplex virus type 2 assay.     

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.     

Calyciphyllines H-M, new Daphniphyllum alkaloids from Daphniphyllum calycinum

Six new Daphniphyllum alkaloids, calyciphyllines H-M (1-6), were isolated from the leaves and stems of Daphniphyllum calycinum (Daphniphyllaceae). The structures and relative stereochemistry of 1-6 were elucidated on the basis of spectroscopic data, and the absolute stereochemistry of 3 was assigned by PGME method.     

New pyrrolidine alkaloids from the roots of Pandanus amaryllifolius

Four new alkaloids, pandamarilactonines-E, -F, and -F-N-oxide consisting of a pyrrolidine moiety and two α-methyl-γ-lactone residues, and pandamarilactonine-G, possessing a pyrrolidinone function, were isolated from the roots of Pandanus amaryllifolius. Their structures were determined based on spectroscopic analyses and chemical syntheses.     

New oxindole and indole alkaloids from Gelsemium rankinii

Six new humantenine-type (1-6) and two new gelsemine-type (7, 8) oxindole alkaloids and one new indole alkaloid (9) were isolated from the leaves and branches of Gelsemium rankinii. The structures of the new alkaloids were determined by spectroscopic analyses. Among them, 6-hydroxyhumantenine (5) is the first example of a Gelsemium alkaloid with an oxygen function at C-6 position, and is a plausible biogenetic precursor of gelsemine-type alkaloids.     

Caldaphnidines A-F, six new Daphniphyllum alkaloids from Daphniphyllum calycinum

Six new Daphniphyllum alkaloids, namely caldaphnidines A-F (1-6), together with eight known ones, deoxycalyciphylline B, deoxyisocalyciphylline B, bukittiggine, calycicine A, methyl homosecodaphniphyllate, daphnilactone B, and daphnezomines L-M, were isolated from the leaves and the seeds of Daphniphyllum calycinum. The structure of 1 was determined by a single-crystal X-ray diffraction study, and the structures of 2-6 were established by spectral methods, especially two-dimensional NMR techniques (¹H-¹H COSY, HMQC, HMBC, and NOESY).     

Cannabioxepane, a novel tetracyclic cannabinoid from hemp, Cannabis sativa L.

Apart from large amounts of cannabidiol, the known stilbenoids 1-4 and the oxylipins 7 and 8, a fibre cultivar of Cannabis sativa derived from the historical Carmagnola variety gave the novel spiranic stilbenoid isocannabispiradienone (5) and the biphenyl-type cannabinoid cannabioxepane (CBX, 6), a tetracyclic compound characterized by an unprecedented C-5/C-8′ oxygen bridge and devoid of cannabinoid activity. Structures were established by analysis of MS and NMR data, and the biogenetic derivation of the new compounds is discussed.     

Two new tryptamine-derived alkaloids from Chimonanthus praecox f. concolor

A new pyrrolidinoindoline-type alkaloid, CPC-1, and a new tryptamine-derived dimeric alkaloid, CPC-2, were isolated from the seeds and rinds of Chimonanthus praecox f. concolor. The structure including the absolute configuration of CPC-1 was determined by chiral total synthesis. CPC-2 has a unique hexahydropyrroloquinoline skeleton.     

Three new Lycopodium alkaloids from Huperzia carinata and Huperzia squarrosa

Eleven Lycopodium alkaloids with lycodine-type, lycopodine-type, and fawcettimine-related skeletons were isolated from the whole plants of Huperzia carinata (Desv. Ex. Poir.) Trevis and Huperzia squarrosa (G. Forst) Trevis (Huperziaceae). Among them, 8,15-dihydrohuperzine A (2), lycocarinatine A (3), and lycoposerramine U N-oxide (11) are new compounds. The structures of these new alkaloids were elucidated on the basis of 2D NMR correlations. Some of these isolated alkaloids were assayed for acetylcholinesterase (AChE) inhibitory activity.     

Four novel gelsedine-type oxindole alkaloids from Gelsemium elegans

Four new gelsedine-type oxindole alkaloids (1-4) were isolated from the leaves and branches of Gelsemium elegans, together with 10 known alkaloids. The structures of the new alkaloids were determined by spectroscopic analyses and partial synthesis from known compounds. Gelsecrotonidine (1), 14-hydroxygelsecrotonidine (2), and 11-methoxygelsecrotonidine (3) possess an additional C₂ unit with an acetic acid residue compared to gelsenicine-related monoterpenoid indole alkaloids. 14-Hydroxygelsedilam (4) is an 18,19-nor-type monoterpenoid indole alkaloid.     

Lyconadins C and F, new Lycopodium alkaloids from Lycopodium complanatum

New Lycopodium alkaloids, lyconadins C (1) and F (2), were isolated from the club moss Lycopodium complanatum. Lyconadin C (1) is a new C₁₆N₂-type Lycopodium alkaloid possessing unique fused-tetracyclic ring system consisting of a cycloheptene ring fused to a decahydroquinoline and pyridone rings. Lyconadin F (2) possesses a primary amide moiety in its molecular, which is the first example of Lycopodium alkaloids. Biogenetically, lyconadins C (1) and F (2) might be related to lyconadins A (4) and B (5). The structures and relative stereochemistry of 1 and 2 were elucidated on the basis of spectroscopic data. The absolute stereochemistry of 2 was elucidated by chemical correlations with lyconadin B (5) through hemiaminal form of lyconadin F (3).     

Four new colchicinoids, gloriosamines A-D, from Gloriosa rothschildiana

Four new colchicinoids, gloriosamines A-D, were isolated from the aerial parts of Gloriosa rothschildiana. The structure of gloriosamine A, including the absolute configuration, was determined by chemical conversion from colchicine.     

Lannotinidines A-G, new alkaloids from two species of Lycopodium

Seven new Lycopodium alkaloids, lannotinidines A-G (1-7), have been isolated from the club moss Lycopodium annotinum and L. annotinum var. acrifolium. Stereochemistry of 1-7 was elucidated by combination of NOESY correlations and chemical transformation. Lannotinidines B-E (2-5) elevated NGF mRNA expression.     

Spironaamidine, a new spiroquinone-containing alkaloid from the marine sponge Leucetta microraphis

Spironaamidine (1), a unique spiroquinone-containing alkaloid, was isolated from the marine sponge, Leucetta microraphis, along with two known imidazole alkaloids, naamidine H (2) and (9E)-clathridine 9-N-(2-sulfoethyl)imine (3). Spironaamidine (1) showed antimicrobial activity against Bacillus cereus.     

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.     

Lycopladines F and G, new C16N2-type alkaloids with an additional C4N unit from Lycopodium complanatum

Two new Lycopodium alkaloids, lycopladines F (1) and G (2), have been isolated from the club moss Lycopodium complanatum, and the structures and relative stereochemistries of 1 and 2 were elucidated on the basis of spectroscopic data. Lycopladine F (1) is a rare C₁₆N₂-type Lycopodium alkaloid possessing an amino acid residue (C₄N).     

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.