Oldhamiphylline A: a novel hexacyclic alkaloid from Daphniphyllum oldhami

A novel Daphniphyllum alkaloid, oldhamiphylline A (1), together with five known alkaloids, deoxycalyciphylline B, deoxyisocalyciphylline B, calyciphylline, secodaphniphylline, and calycicine A, was isolated from the leaves of Daphniphyllum oldhami. The structure of 1 was established by spectroscopic methods, especially 2D NMR techniques (1H,1H-COSY, HMQC, HMBC, and NOESY).     

Ehretinine,a novel pyrrolizidine alkaloid from Ehretia aspera

The structure for ehretinine, 7-O-(p-methoxybenzoyl)-retronecanol, a new pyrrolizidine alkaloid isolated from leaves of Ehretia aspera has been established by a combination of spectroscopic and chemical methods. To our knowledge this constitutes the first report of the natural occurrence of a retronecanol ester.     

Buchananine,a novel pyridine alkaloid from Cryptolepis buchanani

A new alkaloid, buchananine, was isolated from the stems of Cryptolepis buchanani. Its structure was determined as 6-O-nicotinoyl-α-d-glucopyranose by chemical and spectroscopic investigations.     

Chenoalbicin, a novel cinnamic acid amide alkaloid from Chenopodium album

The roots of Chenopodium album were infused in MeOH, and the extract was partitioned between AcOEt and H2O. AcOEt-Soluble material was subjected to different silica-gel column chromatographies and then purified by reverse-phase HPLC to afford a new cinnamic acid amide alkaloid as a racemic mixture. The new compound, named chenoalbicin (1), was characterized by extensive spectroscopic investigation, especially 1D and 2D NMR spectroscopy. Its effects on the germination and growth of Lactuca sativa L. has been studied. The results are reported as percentage differences of germination, root elongation, and shoot elongation from the control at concentrations ranging from 10(-4) to 10(-7) M.     

Flavonoid glycosides and isoquinolinone alkaloids from Corydalis bungeana

Two flavonol O-glycosides identified as the 3-O-alpha-arabinopyranosyl(1'-->6')-beta-glucopyranoside 7-O-beta-glucopyranosides of kaempferol and quercetin were isolated from the whole plant of Corydalis bungeana Turcz. together with eight known flavonol O-glycosides. Two isoquinolinone alkaloids were also obtained from the same source, including the new derivative, 6,7-methylenedioxy-2-(6-acetyl-2,3-methylenedioxybenzyl)-1(2H)-isoquinolinone. The structures were determined by spectroscopic methods (NMR and high-resolution MS).     

6-Hydroxy-5,6-seco-stemocurtisine: A novel seco-stemocurtisine-type alkaloid

A novel seco-stemocurtisine-type alkaloid, 6-hydroxy-5,6-seco-stemocurtisine was isolated from the aerial parts of Stemona curtisii (Stemonaceae) collected from Trang Province in Thailand. The unprecedented 5,6-seco-pyrido[1,2-a]azepine structure was elucidated by 2D NMR analysis and a single crystal X-ray crystallographic analysis.     

Two novel steroidal alkaloid glycosides from the seeds of Lycium barbarum

Two novel steroidal alkaloid glycosides, lycioside A (1) and lycioside B (2) were isolated from the seeds of Lycium barbarum. Their structures were determined by various spectroscopic analyses. Compounds 1 and 2 showed inhibitory activities with the IC(50) values of 75.3 and 72.8 μM against rat intestinal sucrase, and 63.4 and 59.1 μM against rat intestinal maltase.     

A novel monoterpenoid indole alkaloid with anticancer activity from Melodinus khasianus

A novel monoterpenoid indole alkaloid with unprecedented 6/5/6/4/6 fused rings, khasuanine A (1), was isolated from the roots of Melodinus khasianus. The structure was determined by extensive analysis of its HR-MS, 1D-, and 2D-NMR spectra. Khasuanine A markedly inhibited the proliferation of PC3 cell with IC₅₀ value of 0.45 μM. Further study showed that khasuanine A was able to induce the apoptosis of PC3 cells by activation of caspase 3 and p53, and by inhibition of Bcl-2.     

Ostropella luxurians sp. nov. from the Russian Far East

Ostropella luxurians sp. nov. collected in the Russian Far East is described and illustrated.     

Synthesis and biological evaluation of EC140: a novel folate-targeted vinca alkaloid conjugate

A novel folate conjugate of desacetylvinblastine monohydrazide (DAVLBH), herein referred to as EC140, was designed and evaluated for biological activity against folate receptor (FR)-positive cells and tumors. EC140 was produced by coupling a peptidic analogue of the vitamin folic acid to DAVLBH via an acylhydrazone bond. This water-soluble conjugate was found to retain high affinity for FR-positive cells, and it produced specific, dose-responsive activity in vitro. Initial in vivo tests confirmed EC140's activity in both syngeneic and xenograft models. Hence, enduring complete responses were observed in animals bearing established, subcutaneous tumors prior to therapy using regimens that produced minor toxicity. In contrast, treatment with the unconjugated DAVLBH drug produced nominal efficacy when dosed at its MTD. Overall, EC140's performance in vitro and in vivo warrants further preclinical study before this novel targeted chemotherapeutic is considered for clinical investigation.     

Structural insight into a novel indole prenyltransferase in hapalindole-type alkaloid biosynthesis

FamD1 is a novel CloQ/NphB-family indole prenyltransferase which involves in hapalindole-type alkaloid biosynthesis. Here the native FamD1 structure and three protein-ligand complexes are analyzed to investigate the molecular basis of substrate binding and catalysis. FamD1 adopts a typical ABBA architecture of aromatic prenyltransferase, in which the substrate-binding chamber is found in the central β-barrel. The indole-containing acceptor substrate is bound adjacent to the prenyl donor. Based on the complex structures, a catalytic mechanism of FamD1 is proposed. Functional implications on the sister enzyme FamD2 are also discussed.     

A novel alkaloid, aristopyridinone A and anti-inflammatory phenanthrenes isolated from Aristolochia manshuriensis

A novel alkaloid, aristopyridinone A (1) and a new phenanthrene, aristolamide II (2), were isolated from Aristolochia manshuriensis (Guanmutong) together with eight known phenanthrenes (3-10). All structures were elucidated by spectroscopic methods. Compound 2 showed a selective inhibitory effect on elastase release by human neutrophils in response to fMLP with an IC₅₀ value of 4.11 μg/mL. Compound 7 exhibited significant inhibitory effects on superoxide anion generation and elastase release with IC₅₀ values of 0.12 and 0.20 μg/mL, respectively.     

Nummularine-O,a cyclopeptide alkaloid from Zizyphus nummularia

In addition to the known peptide alkaloid jubanine-B, a new peptide alkaloid, nummularine-O, has been isolated from the stem bark of Zizyphus nummularia and their structures have been elucidated by chemical and spectroscopic methods.     

Sativanine-g,a cyclopeptide alkaloid from Zizyphus sativa

In addition to the already described peptide alkaloids from the bark of Zizyphus sativa, a new compound of this class, sativanine-G, has been isolated and its structure elucidated. This alkaloid contains a 13-membered ring system and belongs to the nummularine-C class.     

Glycolone,a quinolone alkaloid from Glycosmis pentaphylla

Glycolone, a quinolone alkaloid has been isolated from the leaves of Glycosmis pentaphylla. The structure of the compound has been established as 4,8-dimethoxy-3-(3-methyl but-2-enyl)-2-quinolone from physical and chemical evidences.