11-Isopropylcryptolepine: A novel alkaloid isolated from cryptolepis sanguinolenta characterized using submicro NMR techniques

A new alkaloid has been isolated from extracts of the West African plant Cryptolepis sanguinolenta and identified by submicro NMR techniques as 11-isopropylcryptolepine (1). The unusual incorporation of the isopropyl group at the 11-position of the indolo[3,2-b]quinoline nucleus is suggestive of a mixed biosynthetic origin for the alkaloid.     

Koniamborine, the first pyrano[3,2-b]indole alkaloid and other secondary metabolites from Boronella koniambiensis

Two new alkaloids, (-)-cis-1,2-dihydroxy-1,2-dihydromedicosmine (3) and koniamborine (4), have been isolated from Boronella koniambiensis aerial parts. Their structures have been established from NMR and mass data. Koniamborine is a novel type of alkaloid, which derives from the pyrano[3,2-b]indole basic skeleton, described for the first time from nature. 6-Methoxy-1-methylisatin, also present in the plant material, can be considered biogenetically as a degradation product of the fused pyrone ring of 4.     

大青叶的化学成分研究

目的：对十字花科植物菘蓝Isatis indigotica Fort.叶的化学成分进行研究。方法：大青叶的干燥叶用80%乙醇提取,依次用石油醚,醋酸乙酯,正丁醇萃取,对醋酸乙酯部分采用硅胶、Sephadex LH-20, Rp-8, Rp-18柱色谱进行分离纯化,通过波谱数据分析(MS,¹H-NMR,¹³C-NMR)进行结构鉴定。结论：从醋酸乙酯部分分离鉴定了11个化合物,其中5个生物碱,2个芳香酸,2个木脂素,2个黄酮。分别鉴定为：10H-indolo［3,2-b］quinoline(1),靛玉红(2),4(3H)-喹唑酮(3),(E)-3-(3′,5′-dimethoxy-4′-hydroxybenzylidene)-2-indolinone(4),deoxyvascinone(5),苯甲酸(6),邻羟基苯甲酸(7),(-)-落叶松脂素(8),(+)-异落叶松树脂醇(9),异牡荆素(10),6-β-D-glucopyranosyldiosmetin(11)。其中化合物1,4,5,8,9,11为首次从大青叶中分离得到。     

Alkaloids from the root of Isatis indigotica

Seventeen new alkaloids (1-17) and 14 known analogues have been isolated from an aqueous extract of the root of Isatis indigotica. The structures and absolute configurations of these compounds were determined by extensive spectroscopic data analysis, including 2D NMR, single-crystal X-ray crystallography using anomalous scattering of Cu Kα radiation, and electronic circular dichroism spectra calculations based on the quantum-mechanical time-dependent density functional theory. Compounds 1, 2, and 3 are the first examples of natural products with unique linkages between a molecule of 2-(4-methoxy-1H-indol-3-yl)acetonitrile and 2-(1H-indol-3-yl)acetonitrile, 2-(4-methoxy-1H-indol-3-yl)acetonitrile, and 4-hydroxyphenylethane, respectively. Compounds (-)-4 and (+)-4 represent the first natural products with the pyrrolo[2,3-b]indolo[5,5a,6-b,a]quinazoline skeleton. Some structural assignments for the new alkaloids suggest that the assignments made for certain previously reported alkaloids require revision. Compounds 1-3 and arvelexin (18) show antiviral activity against the influenza virus A/Hanfang/359/95 (H3N2), with IC(50) values of 3.70-12.35 μM, and 17 inhibits Coxsackie virus B3 replication with an IC(50) of 6.87 μM.     

Antimicrobial isopropenyl-dihydrofuranoisoflavones from Crotalaria lachnophora

Two new isopropenyl-dihydrofuranoisoflavones exhibiting antimicrobial properties have been isolated along with eight known compounds from the Cameroonian medicinal plant Crotalaria lachnophora. The structures of the new compounds were elucidated by 1D and 2D NMR spectroscopy and high-resolution mass spectrometry as 7,2',4'-trihydroxy-5'-isopropenyl-4',5'-dihydrofurano[2',3':5,6]isoflavone (1) and 4,8-dihydroxy-2-isopropenyl-2,3-dihydro-5H-[1]benzofuro[2,3-b]furo[3,2-g]chromen-5-one (2). The CH(2)Cl(2)/MeOH (1:1) extract and the compounds isolated were subjected to in vitro antimicrobial assays against a panel of pathogenic microorganisms, including Gram-positive and Gram-negative bacteria and fungi. The new compounds, named lachnoisoflavones A (1) and B (2), showed moderate inhibitory activities against Escherichia coli and Klebsiella pneumoniae.     

Phelligridins C-F: cytotoxic pyrano[4,3-c][2]benzopyran-1,6-dione and furo[3,2-c]pyran-4-one derivatives from the fungus Phellinus igniarius

Three unique pyrano[4,3-c][2]benzopyran-1,6-dione derivatives and a new furo[3,2-c]pyran-4-one, named phelligridins C-F (2-5), together with hispolon (8), (E)-4-(3,4-dihydroxyphenyl)but-3-en-2-one (9), 4-hydroxybenzaldehyde, protocatechualdehyde, syringic acid, protocatechuic acid, caffeic acid, isoergosterone, and octadecyl ferulate were isolated and identified from the ethanolic extract of Phellinus igniarius. Their structures were determined by spectroscopic methods including IR, MS, and 1D and 2D NMR experiments. The structures of the new compounds were characterized as 3-(4-hydroxystyryl)-8,9-dihydroxypyrano[4,3-c]isochromene-4-one (2), 3-(3,4-hydroxystyryl)-8,9-dihydroxypyrano[4,3-c]isochromene-4-one (3), 8,9-dihydroxy-3-[5',6'-dihydroxy-5' '-methyl-3' '-oxo-spiro[fural-2' '(3' 'H),1'-indene]-2'-yl]-1H,6H-pyrano[4,3-c][2]benzopyran-1,6-dione (4), and (3Z)-3-(3,4-dihydroxybenzylidene)-6-(3,4-dihydroxystyryl)-2,3-dihydro-2-methoxy-2-(2-oxo-propyl)furo[3,2-c]pyran-4-one (5), respectively. Some compounds including 2 and 3 showed in vitro selective cytotoxicity against a human lung cancer cell line (A549) and a liver cancer cell line (Bel7402). Possible biogenetic sequences to the formation of 1-9 are postulated.     

Zyzzyanones B-D, dipyrroloquinones from the marine sponge Zyzzya fuliginosa

Zyzzyanones B, C, and D (2-4), three new dipyrroloquinones with a pyrrolo[3,2-f]indole-4,8(1H,7H)-dione skeleton, have been isolated from the Australian marine sponge Zyzzya fuliginosa. The known zyzzyanone A, makaluvamines C, E, G, H, and L, damirones A and B, 3,7-dimethylguanine, and 4-hydroxybenzoic acid were also isolated. The structures of the new compounds 2-4 were established by extensive NMR spectroscopic data. Compounds 2-4 showed moderate cytotoxic activity against mouse Ehrlich carcinoma cells (IC50 25 microg/mL).     

Studies directed toward the synthesis of cryptoheptine

Synthesis of 5,10-dihydro-10-methylindolo[3, 2-b][1]benzazepin-12(11H)-one (2), an isomer of the reported structure for cryptoheptine (1), is presented. Attempts to convert 2 to 1 led to 10-methylindolo[3,2-b][1]benzazepin-12-one (10), an oxidation product of 2 and presumably 1. These results highlight the potential instability of cryptoheptine and cast doubt on its proposed structure.     

Dimeric aporphine alkaloids of Phoenicanthus obliqua from Sri Lanka.

A new dimeric aporphine alkaloid, phoenicanthusine (1), and six known alkaloids were isolated from the stem bark of Phoenicanthus obliqua. The structure of 1 was elucidated by 1D ((1)H, (13)C) and 2D ((1)H-(1)H COSY, HMQC, HMBC, and NOESY) NMR and HRMS studies. Phoenicanthusine represents the first example of a N-6--C-4' and C-7--C-5' linked dimeric aporphine alkaloid.     

New quinoline alkaloids from Ruta chalepensis

The roots of Ruta chalepensis, collected from the northern Saudi desert, yielded two new quinoline alkaloids, namely, 2-?6'-(2H-benzo[d]1' ',3' '-dioxolen-5' '-yl)hexyl?-hydroquinolin-4-one (1) and 2-?6'-(2H-benzo[d]1' ',3' '-dioxolen-5' '-yl)hexyl?-4-methoxy-quinoline (2). Nine previously reported alkaloids, dictamnine, pteleine, skimmianine, rutacridone, isogravacridonechlorine, maculosidine, graveoline, graveolinine, and 4-methoxy-1-methyl-2(1H)-quinolinone, and coumarins, chalepensin, and umbelliferone were also isolated. Structure elucidations were based primarily on 1D and 2D NMR analyses and chemical transformations. Antimicrobial activity of these compounds is discussed.     

Phytotoxic compounds from Prionosciadium watsoni

Bioassay-guided fractionation of a phytotoxic extract of Prionosciadium watsoni led to the isolation of three new pyranocoumarins and two pyranochromones. The new compounds were characterized as propionic acid (9R,10R)-9-acetoxy-8,8-dimethyl-9,10-dihydro-2H,8H-benzo[1,2-b:3,4-b']dipyran-2-one-10-yl ester (1), isobutyric acid (9R,10R)-9-hydroxy-8,8-dimethyl-9,10-dihydro-2H,8H-benzo[1,2-b:3,4-b']dipyran-2-one-10-yl ester (2), isobutyric acid (9R)-8,8-dimethyl-9,10-dihydro-2H,8H-benzo[1,2-b:3,4-b']dipyran-2-one-9-yl ester (10), 2-methylbut-(2Z)-enoic acid (3R)-5-methoxy-3,4-dihydro-2,2,8-trimethyl-6-oxo-2H,6H-benzo[1,2-b:5,4-b']dipyran-3-yl ester (11), and isobutyric acid (3R)- 5-methoxy-3,4-dihydro-2,2,8-trimethyl-6-oxo-2H,6H-benzo[1,2-b:5,4-b']dipyran-3-yl ester (12) by spectroscopic and chemical methods. The stereochemistry at the stereogenic centers was established by applying the Mosher ester methodology. The structures of 1 and 2 were corroborated by single-crystal X-ray diffraction studies. The phytotoxic activity of the isolated compounds was assessed on Amaranthus hypochondriacus, Echinochloa crus-galli, and Lemna pausicostata. The phytotoxins also modified the electrophoretic mobility of calmodulin from both bovine-brain and spinach.     

Diplopyrone,a new phytotoxic tetrahydropyranpyran-2-one produced by Diplodia mutila,a fungus pathogen of cork oak

A new phytotoxic monosubstituted tetrahydropyranpyran-2-one, named diplopyrone (1), was isolated from the liquid culture filtrates of Diplodia mutila, a plant pathogenic fungus causing a form of canker disease of cork oak (Quercus suber). Diplopyrone was characterized, using spectroscopic and chemical methods, as 6-[(1S)-1-hydroxyethyl]-2,4a,6,8a-tetrahydropyran[3,2-b]pyran-2-one. The absolute stereochemistry of the chiral secondary hydroxylated carbon (C-9), determined by application of Mosher's method, proved to be S. Diplopyrone assayed at a 0.01-0.1 mg/mL concentration range caused necrosis and wilting on cork oak cuttings. On a nonhost plant, tomato, diplopyrone caused brown discoloration or stewing on the stem.     

A new naphthopyrone derivative from Cassia quinquangulata and structural revision of quinquangulin and its glycosides

A novel naphthopyrone derivative, named quinquangulone (1), has been isolated from Cassia quinquangulata, along with the known compounds quinquangulin (2) and its two glycosides (3 and 4), rubrofusarin (5) and its two glycosides (6 and 7), nor-rubrofusarin (8) and its 6-O-glucoside (9), and three stilbenes (10-12). The structure of quinquangulone was established by spectral interpretation as 5,9-dihydroxy-8-methoxy-2,9-dimethyl-6-oxo-4H,6H,9H-naphtho-[2,3-b]pyran-4-one. Reinvestigation of the NMR spectra of quinquangulin led to revision of its structure as 5,6-dihydroxy-8-methoxy-2,9-dimethyl-4H-naphtho[2,3-b]pyran-4-one (2a). The structures of two quinguangulin glycosides, 3 and 4, were also revised accordingly. Compound 2a exhibited activity against Staphylococcus aureus and methicillin-resistant S. aureus (MIC, 3.125 and 6.25 microg/mL, respectively).     

Kinmoonosides A-C, three new cytotoxic saponins from the fruits of Acacia concinna, a medicinal plant collected in myanmar

Three genuine saponins, named kinmoonosides A-C (1-3), have been isolated, together with a new monoterpenoid (4), from a methanolic extract of the fruits of Acacia concinna. The structures of kinmoonosides A-C were elucidated on the basis of spectral analysis as 3-O-?alpha-L-arabinopyranosyl(1-->6)-[beta-D-glucopyranosyl(1-->2) ]-b eta-D-glucopyranosyl?-21-O-?(6R, 2E)-2-hydroxymethyl-6-methyl-6-O-[4-O-(2'E)-6'-hydroxyl-2'-hydroxymet hyl-6'-methyl-2',7'-octadienoyl-beta-D-quinovopyranosyl]-2, 7-octadienoyl?acacic acid 28-O-alpha-L-arabinofuranosyl(1-->4)-[beta-D-glucopyranosyl(1-->3)]-a lpha-L-rhamnopyranosyl(1-->2)-beta-D-glucopyranosyl ester (1); 3-O-?alpha-L-arabinopyranosyl(1-->6)-[beta-D-glucopyranosyl(1-->2) ]-b eta-D-glucopyranosyl?-21-O-?(6S, 2E)-2-hydroxymethyl-6-methyl-6-O-[4-O-(2'E)-6'-hydroxyl-2'-hydroxymet hyl-6'-methyl-2',7'-octadienoyl-beta-D-quinobopyranosyl]-2, 7-octadienoyl?acacic acid 28-O-alpha-L-arabinofuranosyl(1-->4)-[beta-D-glucopyranosyl(1-->3)]-a lpha-L-rhamnopyranosyl(1-->2)-beta-D-glucopyranosyl ester (2); and 3-O-?alpha-L-arabinopyranosyl(1-->6)-[beta-D-glucopyranosyl(1-->2) ]-b eta-D-glucopyranosyl?-21-O-[(2E)-6-hydroxyl-2-hydroxymethyl-6-methyl- 2,7-octadienoyl]acacic acid 28-O-alpha-L-arabinofuranosyl(1-->4)-[beta-D-glucopyranosyl(1-->3)]-a lpha-L-rhamnopyranosyl(1-->2)-beta-D-glucopyranosyl ester (3), respectively. The new monoterpenoid 4 was determined as 4-O-[(2E)-6-hydroxyl-2-hydroxymethyl-6-methyl-2, 7-octadienoyl]-D-quinovopyranose. Compounds 1-3 showed significant cytotoxicity against human HT-1080 fibrosarcoma cells.     

7-deoxy-6-epi-castanospermine, a trihydroxyindolizidine alkaloid glycosidase inhibitor from Castanospermum australe

A new indolizidine alkaloid has been isolated from the seeds of Castanospermum [1] australe and identified as 7-deoxy-6-epi-castanospermine by ms and 1H- and 13C-nmr spectroscopy. The alkaloid is the first trihydroxylated indolizidine to be isolated from this plant and may represent an intermediate in the biosynthetic pathway to the tetrahydroxy-indolizidines and -pyrrolizidines. It inhibits amyloglucosidase and yeast alpha-glucosidase but is significantly less active as a glycosidase inhibitor than its isomer swainsonine [2] and the tetrahydroxylated alkaloids castanospermine [3], 6-epi-castanospermine [4], and australine [5].     

6-�л�-3-����-7H-����[3,2-b]-1,2,4-���-7-ͪ�໯����ĺϳɼ�������������ø���ƻ���

??OBJECTIVE To explore the synthesis and acetylcholinesterase inhibitory activity of 6-benzyl-3-aryl-7H-thiazolo[3,2-b]-1,2,4-triazin-7-one derivatives. METHODS Benzaldehyde and acetylglycine were used as raw materials and underwent Erlenmeyer-Pl??chl reaction, condensation reaction, hydrolysis reaction, condensation reaction to obtain 6-benzyl-3-thioxo-3,4-dihydro-1,2,4-triazin-5(2H)-ones derivatives. The derivatives reacted with substituted ??-phenacyl chlorides to generate 6-benzyl-3-(hydroxylaryl)-7H-thiazolo[3,2-b]-1,2,4-triazin-7-ones derivatives. Then, Williamson reaction was used to yield 6-benzyl-3-aryl-7H-thiazolo[3,2-b]-1,2,4-triazin-7-ones as target compounds. RESULTS Nine 6-benzyl-3-aryl-7H-thiazolo[3,2-b]-1,2,4-triazin-7-ones were prepared as target compounds. All target compounds exhibited inhibitory activities against human AChE in vitro, five of which had inhibitory rates above 50% at 10 ??mol??L^-1. CONCLUSION Based on the screening results of AChE inhibitory activity in vitro and docking studies, there are some interactions between 6-benzyl-3-aryl-7H-thiazolo[3,2-b]-1,2,4-triazin-7-one derivatives and the anionic binding site and PAS zones of AChE, and the target compounds have exhibited AChE inhibitory activities.     

小黄皮茎的化学成分及生物活性研究

目的研究小黄皮Clausenaemarginata茎的化学成分及其保肝活性。方法采用硅藻土、硅胶等多种柱色谱、中压制备液相色谱(MPLC)及制备型HPLC等方法对小黄皮茎的化学成分进行分离纯化,根据化合物理化性质结合现代波谱学方法鉴定化合物结构;并测试其对DL-半乳糖胺诱导肝细胞损伤的保护活性及其对脂多糖(LPS)诱导小鼠小胶质BV2细胞产生一氧化氮(NO)的抑制活性。结果从小黄皮茎的95%乙醇提取物的氯仿部位分离得到11个化合物,分别鉴定为nordentatin(1)、oxanordentatin(2)、5′-羟基葡萄内酯(3)、7-[(E)-7′-羟基-3′,7′-二甲基-2′,5′-二烯]-香豆素(4)、7-羟基香豆素(5)、claulamine A(6)、γ-崖椒碱(7)、开环异落叶松脂素(8)、2-{4-[(1E)-3-hydroxyprop-1-en-1-yl]-2,6-dimethoxyphenoxy}propane-1,3-diol(9)、2-[4-(3-hydroxy-1-propenyl)-2-methoxyphenoxy]-1,3-propanediol(10)、甲基-2-O-β-D-吡喃葡萄糖基苯甲酸(11)。其中,化合物1~5为香豆素类化合物,6为咔唑生物碱,7为呋喃喹啉类生物碱,8为木脂素类化合物,9、10为苯丙素类化合物,11为酚酸类化合物。结论化合物2~4、7~11为首次从该植物中分离得到,化合物5和7对DL-半乳糖胺诱导的肝细胞损伤具有一定的保护活性,化合物11对LPS诱导BV2细胞产生NO具有一定的抑制作用。     

Phenolic compounds from the roots of Jordanian viper's grass, Scorzonera judaica

Nine new phenolic compounds, 3S-hydrangenol 40-O-R-L-rhamnopyranoysl-(1-->3)-β-D-glucopyranoside (1), thunberginol F 7-O-β-D-glucopyranoside (2), 2-hydroxy-6-[2-(4-hydroxyphenyl)-2-oxo-ethyl]benzoic acid (3), 2-hydroxy-6-[2-(3,4-dihydroxyphenyl)-2-oxo-ethyl]benzoic acid (4), 2-hydroxy-6-[2-(3,4-dihydroxyphenyl-5-methoxy)-2-oxoethyl]benzoic acid (5), hydrangeic acid 40-O-β-D-glucopyranoside (6), E-3-(3,4-dihydroxybenzylidene)-5-(3,4-dihydroxyphenyl)dihydrofuran-2-one (7), Z-3-(3,4-dihydroxybenzylidene)-5-(3,4-dihydroxyphenyl)-2(3H)-furanone (8), and 4-[β-D-glucopyranosyl)hydroxy]-pinoresinol (9), and nine known compounds were isolated from the roots of Scorzonera judaica. Structures of 1-9 were elucidated by mass spectrometry, extensive 1D and 2D NMR spectroscopy, and CD spectroscopy.All compounds were evaluated for cytotoxic activity.     

Macrocyclic pyrrolizidine alkaloids from Senecio anonymus. Separation of a complex alkaloid extract using droplet counter-current chromatography

Ten 12-membered macrocyclic pyrrolizidine alkaloids, all of them esters of the necines, retronecine or otonecine, have been isolated from Senecio anonymus. The separation, carried out by droplet counter-current chromatography, afforded senecionine [1], integerrimine [2], retrorsine [3], senkirkine [5], neosenkirkine [6], otosenine [10], hydroxysenkirkine [7], and a new alkaloid given the trivial name anonamine [9]. Traces of usaramine [4] and another new alkaloid, hydroxyneosenkirkine [8], were detected by 1H nmr. In addition, the previously unreported 3a beta-hydroxy-4-ethoxy-2,6-perhydroindoledione [11] was isolated. X-ray structures were obtained for neosenkirkine [6], hydroxysenkirkine [7], anonamine [9], and [11]. 1H-13C heteronuclear shift correlated nmr (HETCOR) provided unambiguous chemical shift assignments for 13C-nmr data. Antitumor activity was assayed using the A204-rhabdomyosarcoma cell line in soft agarose.     

Acetylcholinesterase inhibitory potential of a carbazole alkaloid,mahanimbine, from Murraya koenigii

In the search for acetylcholinesterase (AChE) inhibitors from Indian medicinal plants, via bioassay‐guided isolation, a carbazole alkaloid, mahanimbine [3, 5‐dimethyl‐3‐(4‐ methylpent‐3‐enyl)‐11H‐pyrano [5, 6‐a] carbazole], was isolated from the petroleum ether extract of the leaves of Murraya koenigii. Inhibition of AChE was evaluated based on Ellman's method using 96‐well microplate readers. Mahanimbine inhibited AChE activity in a dose‐dependent manner with an IC₅₀ value of 0.03 ± 0.09 mg/mL, while galantamine was used as a standard. The AChE inhibitory activity of this carbazole alkaloid has not been reported so far, and this study is the first to reveal this activity in carbazole alkaloid mahanimbine, isolated from Murraya koenigii. Copyright © 2009 John Wiley & Sons, Ltd.