Identification of a new naphthalene and its derivatives from the bulb of eleutherine americana with inhibitory activity on lipopolysaccharide-induced nitric oxide production

A new naphthoquinone, (-)-3-[2-(acetyloxy)propyl]-2-hydroxy-8-methoxy-1,4-naphthoquinone (1) was isolated from the bulb of Eleutherine americana MERR. et HEYNE (Iridaceae) together with two known compounds, eleutherinol (6) and 1,5-dihydroxy-3-methylanthraquinone (7) which were found in this species for the first time. The other known compounds, (-)-isoeleutherin (2), (+)-eleutherin (3), (-)-hongconin (4), and (+)-dihydroeleutherinol (5) which were reported previously from this species, were also isolated in the present study. Compounds 2-6 exhibited potent inhibitory activity on nitric oxide production in RAW 264.7 lipopolysaccharide-activated mouse macrophage cells with IC(50) values of 7.7, 11.4, 19.8, 21.7, and 34.4 microM, respectively, whereas the other two compounds, 1 and 7, were inactive. The structure of compound 1 was elucidated by spectroscopic data analysis including 1D and 2D NMR experiments.     

日香桂根的化学成分研究（III）

利用柱层析法（硅胶,C18）从日香桂根的乙酸乙酯提取物中分离出8个单体化合物［女贞苷(1),连翘苷（2）,(+)-羟基松脂醇-1-O-β-D-葡萄糖(3),(+) 环橄榄树脂素(4), 2α,3β-二羟基乌苏-12-烯-28酸(5),对羟基苯乙醇(6),(-) 橄榄脂素(7)和橄榄树脂素-4-O-β-D-葡萄糖苷(8)］,其结构经₁H NMR和¹³C NMR确证。5为首次在木犀科植物中发现,4为首次在木犀属植物中发现,2, 3, 7和8为首次在日香桂植物中发现。     

Medicinal foodstuffs. XXXIV. Structures of new prenylchalcones and prenylflavanones with TNF-alpha and aminopeptidase N inhibitory activities from Boesenbergia rotunda

The methanolic extract from the rhizomes of Boesenbergia rotunda (Zingiberaceae) was found to show inhibitory effect on tumor necrosis factor-alpha (TNF-alpha)-induced cytotoxicity in L929 cells (IC(50)=6.1 microg/ml). By bioassay-guided separation, four new prenylcalcones, (+)-krachaizin A (1a), (-)-krachaizin A (1b), (+)-krachaizin B (2a), and (-)-krachaizin B (2b), and four new prenylflavanones, rotundaflavones Ia (3a), Ib (3b), IIa (4a), and IIb (4b), were isolated together with 18 known constituents (5a-7b and 8-19). The structures of eight new compounds were elucidated on the basis of physicochemical evidence. Among them, (+)-krachaizin B (2a), (-)-krachaizin B (2b), (+)-4-hydroxypanduratin A (6a), (-)-4-hydroxypanduratin A (6b), (+)-isopanduratin A (7a), (-)-isopanduratin A (7b), alpinetin (10), cardamonin (14), and 2,6-dihydroxy-4-methoxydihydrochalcone (15) significantly inhibited TNF-alpha-induced cytotoxicity in L929 cells at 10 microM. In addition, 2a, 2b, (+)-panduratins A (5a), (-)-panduratin A (5b), 6a, 7b, and geranyl-2,4-dihydroxy-6-phenylbenzoate (17) were found to show strong inhibitory effects on aminopeptidase N activity.     

Anti-inflammatory and antioxidant components from Hygroryza aristata

Twenty-six known compounds and two new compounds, including a new lignan, (7S*,8R*,7'R*,8'S*)-icariol A?-9-O-β-xylopyranoside (1), and a new indole alkaloid, hygarine (2), were isolated from the extracts of Hygroryza aristata (Gramineae). The structures of all compounds were elucidated on the basis of NMR spectral analysis. The compounds (-)-epigallocatechin-3-O-gallate (4) and (-)-epicatechin-3-O-gallate (5) possess free radical scavenging activities and compound 1 could inhibit superoxide anion generation and elastase release by fMLP/CB-induced human neutrophils with IC?? values of 19.33 ± 0.86 and 24.14 ± 1.59 μM, respectively.     

The anti-HBsAg (human type B hepatitis, surface antigen) and anti-HBeAg (human type B hepatitis, e antigen) C18 dibenzocyclooctadiene lignans from Kadsura matsudai and Schizandra arisanensis

The C(18) dibenzocyclooctadiene lignans including three novel schizanrin F (1), G (2), H (3), along with the known kadsurarin (4), were isolated from Kadsura matsudai. A new C(19) homolignan named schiarisanrin E (5), together with the known C(18) lignans, gomisin B (6), G (7) and (+)-gomisin K(3) (8) were obtained from Schizandra arisanensis. Gomisin B, G and (+)-gomisin K(3) showed moderate to strong activity for antihepatitis in anti-HBsAg (human type B hepatitis, surface antigen) and/or anti-HBeAg (human type B hepatitis, e antigen) tests. The structural elucidations of new compounds 1-3 and 5 were based on two-dimensional (2D) NMR techniques including COSY, HMQC, HMBC, NOESY and CD spectra. Preliminary structure-activity relationship studies for these isolated lignans are also discussed.     

Synthesis and characterization of cyano-substituted carborane-based compounds. Molecular structure of [1-(4-C7H7)-12-(C5H3-3-(CN)-3,4-(CH3)2)-C2B10H10

The reaction of cyanogen chloride with [1-(4-C(7)H(7))-12-(C(5)H(3)-3,4-(CH(3))(2))-C(2)B(10)H(10)] (7) was found to yield two new C(5)-substituted carborane cluster-based compounds, [1-(4-C(7)H(7))-12-(C(5)H(2)-3-(CN)-3,4-(CH(3))(2))-C(2)B(10)H(10)] (8) and [1-(4-C(7)H(7))-12-(C(5)H-2,4-(CN)(2)-3,4-(CH(3))(2))-C(2)B(10)H(10)] (9). This cyano-substitution pattern is in contrast to the known substitution for the analogous organic quinarene[5.6.7] system. The observed unique cluster-based products may be understood by a combination of steric and electronic effects. Compounds 8 and 9 were characterized by complete multinuclear NMR, (1)H-(1)H COSY NMR, (1)H-(13)C HMQC NMR, FTIR, UV-Vis, IR, MS data and a single crystal analysis for 8 [X-ray data for 8: C(17)H(25)B(10)N, monoclinic, space group P2(1)/n with cell constants a = 8.6794(17) ?, b = 11.021(2) ?, c = 43.175(9) ?, β = 91.00(3)°, V = 4129.2(14) ?(3), Z = 8, R(1) = 0.0729, wR(2) = 0.1464].     

Lignans and Triterpenes from the Root of Pseuderanthemum carruthersii var. atropurpureum

Two new lignans, pseuderesinol (1), pseuderanoside (2) and a new triterpene, pseuderanic acid (3) were isolated from the dried root of Pseuderanthemum carruthersii (SEEM.) GUILL. var. atropurpureum (BULL.) FOSB. (Acanthaceae), together with ten known compounds, including five lignans, (+)-eudesmin (4), (+)-magnolin (5), (+)-syringaresinol (6), (+)-episyringaresinol (7), (+)-1-hydroxysyringaresinol (8) and five triterpenes, squalene (9), oleanolic acid (10), lupeol (11), betulin (12), betulinic acid (13). Their chemical structures were elucidated by 1D- and 2D-NMR, computational quantum chemistry, as well as high resolution-electrospray ionization (HR-ESI)-MS spectroscopic analysis. The acetylcholinesterase inhibition and cytotoxic activities against HeLa and MCF-7 cancer cell lines were evaluated on some purified compounds at the concentration of 100?μg/mL. Pseuderesinol (1) and magnolin (5) exhibited moderate cytotoxic activities against the MCF-7 cancer cell line.     

New extended magnetic systems based on oxalate and iron(III) ions

A series of oxalate-bridged iron(III) complexes have been synthesized by the reaction of FeCl 3 with oxalic acid (H 2ox) and XCl, where X is a substituted univalent ammonium or an alkaline cation. We have obtained basically two different types of compounds by varying the nature and the shape of the counterion, with the dimensionality of the resulting product being strongly influenced by the counterion. Three-dimensional (3D) networks of oxo- and oxalato-bridged iron(III) ions of the general formula {X 2[Fe 2O(ox) 2Cl 2]. pH 2O} n have been obtained for X = Li (+) ( 1), Na (+) ( 2), and K (+) ( 3) with p = 4 and X = MeNH 3 (+) ( 4), Me 2NH 2 (+) ( 5), and EtNH 3 (+) ( 6) with p = 2. Similar 3D hydroxo- and oxalato-bridged iron(III) networks of the formula {X[Fe 2(OH)(ox) 2Cl 2].2H 2O} n resulted for X = EtNH 3 (+) ( 7a) and PrNH 3 (+) ( 8). Compound 7a undergoes a solid-to-solid transformation, leading to a new species of the formula {(H 3O)(EtNH 3)[Fe 2O(ox) 2Cl 2].H 2O} n ( 7b). Chainlike compounds of the formula {X 2[Fe 2(ox) 2Cl 4]. pH 2O} n [X = Me 2NH 2 (+)( 9, p = 1), Me 3NH (+) ( 10, p = 2), and Me 4N (+) ( 11, p = 0)] have been obtained for the bulkier alkylammonium cations. Magnetic susceptibility measurements in the temperature range 1.9-295 K show the occurrence of weak ferromagnetic ordering due to spin canting in the 3D networks 1- 8, with the value of the critical temperature ( T c) varying with the cation in the range 26 K ( 2) to 70 K ( 8) without significant structural modifications. The last three one-dimensional compounds exhibit the typical behavior of antiferromagnetically coupled chains of interacting spin sextets [ J = -8.3 ( 9), -6.9 ( 10), and -8.4 ( 11) cm (-1) with H = - J summation operator i S i S i+1 ].     

Blue-luminescent/electroluminescent Zn(II) compounds of 7-azaindole and N-(2-pyridyl)-7-azaindole: Zn(7-azaindole)2(CH3COO)2, Zn(NPA)(CH3COO)2, and Zn(NPA)((S)-(+)-CH3CH2CH(CH3)COO)2 (NPA = N-(2-pyridyl)-7-azaindole)

A new 7-azaindole zinc(II) compound, Zn(7-azaindole)2(CH3COO)2 (1), a new ligand N-(2-pyridyl)-7-azaindole (NPA), and two NPA zinc(II) complexes, Zn(NPA)(CH3COO)2 (2) and Zn(NPA)((S)-(+)-CH3CH2CH(CH3)COO)2 (3), have been synthesized and structurally characterized. Compound 1 has a tetrahedral geometry, whereas compounds 2 and 3 have irregular six-coordinate geometry. The NPA ligand in compounds 2 and 3 functions as a bidentate chelate to the zinc center. Compound 1 has a blue luminescence in the solution and the solid state. Compounds 2 and 3 emit a blue color in the solid state. In solution, compounds 2 and 3 are fluxional, as established by 1H NMR experiments. Compound 1 is thermally stable, whereas compounds 2 and 3 undergo decomposition when heated in the solid state. A blue electroluminescent device using compound 1 as the emitting layer has been fabricated. Crystal data: NPA, monoclinic, P2(1)/c, a = 13.993(5) A, b = 8.456(3) A, c = 16.886(5) A, beta = 104.666(12) degrees, V = 1932.9(11) A3; 1, triclinic, P1, a = 9.5114(18) A, b = 10.460(7) A, c = 11.002(3) A, alpha = 117.18(3) degrees, beta = 103.287(18) degrees, gamma = 90.94(2) degrees, V = 938.3(7) A3; 2, monoclinic, C2/c, a = 13.234(6) A, b = 9.373(3) A, c = 13.956(7) A, beta = 113.24(3) degrees, V = 1590.7(12) A3; 3, monoclinic, P2(1), a = 11.047(7) A, b = 15.343(9) A, c = 13.785(8) A, beta = 100.123(9) degrees, V = 2300(2) A3.     

Group 6 heteroatom- and non-heteroatom-stabilized carbene complexes. beta,beta'- and alpha,beta,beta'-annulation reactions of cyclic enamines

Cyclization reactions of group 6 Fischer carbene complexes with cyclopentanone and cyclohexanone enamines are described. Enamine 3a undergoes thermal alpha,beta,beta'-annulation with alkenylcarbene complexes 1 and 2 (THF, 60 degrees C), affording semibullvalenes 5. The metalate intermediates 6, resulting from beta,beta'-annulation of the enamines 3a and 4a, were quantitatively formed by running the reaction in hexane at room temperature. Acid-promoted demetalation of 6 afforded endo-2-bicyclo[3.2.1]octen-8-ones 7 and endo/exo-2-bicyclo[3.3.1]nonen-9-ones 8 (endo/exo = 5:1). Using (S)-methoxymethylpyrrolidine-derived enamines 3b and 4b,c allowed highly enantioenriched cycloadducts endo-(+)-7 as well as endo-(-)-8 and exo-(-)-8 to be accessed. The non-heteroatom-stabilized carbene complex 10 was formed from complex 6 by Me(3)SiOTf-promoted elimination of the methoxy group, characterized by (13)C NMR, and transformed into the organic compounds 7, 7-d, and 11 as well as into bicyclo[3.2.1]octan-2,8-diones 14 and cycloheptanones 15. On the basis of this sequence, enantioenriched cycloheptanones (+)-15 were efficiently prepared in one pot from carbene complexes 2 and enamine 3b (51-55% yield, 91-96% ee). Extension of this work to simple Fischer carbene complexes 16 allowed an appropriate way to generate the nonstabilized pentacarbonyl[(phenyl(alkyl)carbene]tungsten complex 17 to be designed, for which the thermal and chemical behavior leading to compounds 18-21 is described.     

Cembranoid diterpenes and a briarane diterpene from corals

Two new cembrane diterpenes (+)-polydactylide (1) and (+)-7alpha,8beta-dihydroxydeepoxysarcophine (2) together with (+)-sarcophine (3) and (+)-sarcophytoxide (4) have been isolated from the soft coral Sinularia polydactyla. The new cembrane diterpene (-)-7beta-hydroxy-8alpha-methoxydeepoxysarcophine (5) has been obtained from the soft coral Sarcophyton trocheliophorum and the known briarane diterpene briaexcavatolide W (6) from the gorgonian coral Briareum sp.The structures were determined primarily by NMR spectroscopy. The assignment of NMR signals was performed by means of (1)H-(1)H COSY, ROESY, HMQC and HMBC experiments.     

Structural and solid state 31P NMR studies of the four-coordinate copper(I) complexes [Cu(PPh3)3X] and [Cu(PPh3)3(CH3CN)]X

The tris(triphenylphosphine)copper(I) complexes [(PPh3)3CuX] for X = Cl (1), Br (2), I (3), ClO4 (4), BF4 (5), [(PPh3)3CuCl].CH3CN (1a), [Cu(PPh3)3(CH3CN)]X for X = ClO4 (6), BF4 (7), and [Cu(PPh3)3(CH3CN)]X.CH3CN for X = SiF5 (8), PF6 (9) have been studied by solid state 31P CP/MAS NMR spectroscopy together with single crystal X-ray diffraction for compounds (6)-(9), the latter completing the availability of crystal structure data for the series. Compounds (1)-(5) form an isomorphous series in space group P3 (a approximately 19, c approximately 11 A) with three independent molecules in the unit cell, all disposed about 3-fold symmetry axes. Average values (with estimated standard deviations) for the P-Cu-P, P-Cu-X bond angles and Cu-P bond lengths in compounds (1)-(3) are 110.1(6) degrees, 108.8(6) degrees and 2.354(8)A and 115.2(6) degrees, 102.8(9) degrees and 2.306(9)A for compounds (4) and (5). For the acetonitrile solvated compound (1a), the corresponding parameters are 115(4) degrees, 103(3) degrees and 2.309(3)A. The solid state 31P CP/MAS NMR quadrupole distortion parameters, dnu Cu, for (1)-(3) and (1a) are all less than 1 x 10(9) Hz2, despite the changes in donor properties of the halide in (1)-(3), and the coordination geometry of the P3CuX core in (1a). Change of anion to ClO4- and BF4- in compounds (4) and (5) results in a significant increase of dnu Cu to 4.4-5.2 10(9) Hz2 and 5.2-6.0 x 10(9) Hz2, respectively. Compounds (6) and (7) crystallise as isomorphous [Cu(PPh3)3(CH3CN)]X salts in space group Pbca, (a approximately 17.6, b approximately 22.3, c approximately 24.2 A), while compounds (8) and (9) crystallize as isomorphous acetonitrile solvated salts [Cu(PPh3)3(CH3CN)]X.CH3CN in space group P1(a approximately 10.5, b approximately 13.0, c approximately 19.5 A, alpha approximately 104, beta approximately 104, gamma approximately 94 degrees). The P3CuN angular geometries in all four compounds are distorted from tetrahedral symmetry with average P-Cu-P, P-Cu-N angles and Cu-P bond lengths of 115(4) degrees, 103(4) degrees and 2.32(1)A, with dnu Cu ranging between 1.3 and 2.5 x 10(9) Hz2. The solid state 29Si CP/MAS NMR spectrum of the pentafluorosilicate anion in compound (8) is also reported, affording 1J(29Si, 19F) = 146 Hz.     

Hindered axial-equatorial carbonyl exchange in an Fe(CO)(4)(PR(3)) complex of a rigid bicyclic phosphine

Variable-temperature (13)C NMR spectra for a series of Fe(CO)(4)(PR(3)) complexes ligated by phosphatri(3-methylindolyl)methane (1), phosphatri(pyrrolyl)methane (2), P(N-3-methylindolyl)(3) (3), and P(N-pyrrolyl)(3) (4) are reported. Ligand 2 was prepared by reaction of tri(pyrrolyl)methane with PCl(3) in THF and Et(3)N. Compound 2 is stable to methanolysis, hydrolysis, and aerial oxidation at room temperature. Reactions of 2 with selenium powder and Rh(acac)(CO)(2) yield phosphatri(pyrrolyl)methane selenide (5) and Rh(acac)(CO)(2) (6), respectively. The carbonyl stretching frequency in the IR spectrum of 6 and the magnitude of (1)J(Se)(-)(P) in the (31)P NMR spectrum of 5 indicate that 2 is a strong pi-acid and a weak sigma-base, commensurate with its lack of reactivity with CH(3)I. The trend in the decreasing basicity of 2 and related phosphines and phosphites was determined to be P(NMe(2))(3) > 3 > 4 > 1 > P(OPh)(3) > 2. IR data for a series of Rh(acac)(CO)(PR(3)) complexes indicate the trend in decreasing pi-acceptor ability to be 2 approximately 1 > 4 > P(OPh)(3) > 3 > PPh(3). Phosphines 1-4 were reacted with Fe(2)(CO)(9) to yield Fe(CO)(4)(1) (7), Fe(CO)(4)(2) (8), Fe(CO)(4)(3) (9), and Fe(CO)(4)(4) (10), respectively. IR data for 7-10 support the trend in pi-acidity listed above. Variable-temperature (13)C NMR spectra for compounds 8-10 show a single doublet resonance for the carbonyls in the temperature range from -80 to 20 degrees C indicative of rapid intramolecular rearrangement of carbonyls between axial and equatorial sites. However, the (13)C NMR spectrum for 7 shows slowed axial-equatorial carbonyl exchange at 20 degrees C. The limiting slow-exchange spectrum is observed at -20 degrees C. Hindered carbonyl exchange in 7 is attributed to the rigid 3-fold symmetry and steric bulk of 1. In addition to characterization of the new compounds by NMR ((1)H, (13)C, and (31)P) spectroscopy, IR spectroscopy, mass spectrometry, and elemental analysis, compounds 2, 7, 9, and 10 were further characterized by X-ray crystallography.     

New isoflavones and flavanol from Iris potaninii

Two new isoflavones, 6, 3', 4'-trimethoxy-7, 8, 5'-trihydroxyisoflavone (1), 7, 4'-dimethoxy-8, 3', 5'-trihydroxy-6-O-beta-D-glucopyranosylisoflavone (2), and 5, 3, 3'-trihydroxy-7, 4'-dimethoxyflavanone (3) have been isolated from the underground parts of Iris potaninii along with known isoflavones (4-8) and iriflophenone (9). The structures of the new compounds were determined using NMR and mass spectroscopic methods.     

Xanthones from Garcinia mangostana (Guttiferae)

Studies on the stem of Garcinia mangostana have led to the isolation of one new xanthone mangosharin (1) (2,6-dihydroxy-8-methoxy-5-(3-methylbut-2-enyl)-xanthone) and six other prenylated xanthones, alpha-mangostin (2), beta-mangostin (3), garcinone D (4), 1,6-dihydroxy-3,7-dimethoxy-2-(3-methylbut-2-enyl)-xanthone (5), mangostanol (6) and 5,9-dihydroxy-8- methoxy-2,2-dimethyl-7-(3-methylbut-2-enyl)-2H,6H-pyrano-[3,2-b]-xanthene-6-one (7). The structures of these compounds were determined by spectroscopic methods such as 1H NMR, 13C NMR, mass spectrometry (MS) and by comparison with previous studies. All the crude extracts when screened for their larvicidal activities indicated very good toxicity against the larvae of Aedes aegypti. This article reports the isolation and identification of the above compounds as well as bioassay data for the crude extracts. These bioassay data have not been reported before.     

Using diffusion NMR to characterize guanosine self-association: insights into structure and mechanism

This paper presents results from a series of pulsed field gradient (PFG) NMR studies on lipophilic guanosine nucleosides that undergo cation-templated assembly in organic solvents. The use of PFG-NMR to measure diffusion coefficients for the different aggregates allowed us to observe the influences of cation, solvent and anion on the self-assembly process. Three case studies are presented. In the first study, diffusion NMR confirmed formation of a hexadecameric G-quadruplex [G 1](16)4 K(+)4 pic(-) in CD(3)CN. Furthermore, hexadecamer formation from 5'-TBDMS-2',3'-isopropylidene G 1 and K(+) picrate was shown to be a cooperative process in CD(3)CN. In the second study, diffusion NMR studies on 5'-(3,5-bis(methoxy)benzoyl)-2',3'-isopropylidene G 4 showed that hierarchical self-association of G(8)-octamers is controlled by the K(+) cation. Evidence for formation of both discrete G(8)-octamers and G(16)-hexadecamers in CD(2)Cl(2) was obtained. The position of this octamer-hexadecamer equilibrium was shown to depend on the K(+) concentration. In the third case, diffusion NMR was used to determine the size of a guanosine self-assembly where NMR signal integration was ambiguous. Thus, both diffusion NMR and ESI-MS show that 5'-O-acetyl-2',3'-O-isopropylidene G 7 and Na(+) picrate form a doubly charged octamer [G 7](8)2 Na(+)2 pic(-) 9 in CD(2)Cl(2). The anion's role in stabilizing this particular complex is discussed. In all three cases the information gained from the diffusion NMR technique enabled us to better understand the self-assembly processes, especially regarding the roles of cation, anion and solvent.     

Conformational Analysis of Marine Polyhalogenated β-Chamigrenes Through Temperature-Dependent NMR Spectra

Temperature-dependent ¹H- and ¹³C-NMR spectra reveal that polyhalogenated marine β-chamigrenes or synthetic derivatives thereof which are trans-diequatorially, substituted at C(8) and C(9), such as rogiolol ((?)- 2 ), obtusol ((+)- 3 ), and their acetates (+)- 1 and (?)- 4 , undergo slow ring- A chair-chair inversion. Conformational equilibria and kinetics are investigated with the aid of synthetic model compounds and molecular-mechanics calculations. Thus, steric repulsions between Br_ax–C(2) and H_eq–C(7) are seen to disfavour thermodynamically conformers 1b , 2b , 3b , and 4b , which can only be detected through cross-saturation transfer, while additional steric repulsions between Me_ax–C(1) and OH_ax–C(3) make conformer 8b of obtusol epimer so scarcely populated that it can not be detected. In agreement, with (+)- 9 and (+)- 10 , which have a trigonal C(2), two conformers can be directly observed by NMR. The kinetic barriers, which are seen to arise mainly from steric repulsions between H_ax–C(14) and the axial H or halogen atoms at C(8) and C(10), are calculated and discussed with respect to well documented exocycliemethylidene-substituted cyclohexane(ene) systems. This helps to rationalize why in rogiolol acetate ((+)- 1 ) ring B is unusually inert towards Zn/Et₂O/AcOH which causes bromohydrine-group elimination from ring A.     

A new fatty ester and a new triterpene from Skimmia laureola

Aerial parts of Skimmia laureola yielded a new fatty ester, (+)-skimmilaureol (1), and a new triterpene 16-29-dihydroxy, 20-ene cyclolaudenol (2). Five known compounds, namely, O-methyl-cyclolaudenol (3), (R)-7-methoxy-6-(3'-hydroxy-2'R-methoxy-3'-methyl butyl)coumarin (4), (+)-(S)-psi-ribalinine (5), (R)-(+)-ribalinine (6) and methyl isoplatydesmine (7), previously isolated from this plant were subjected to enzymatic bioassays for the first time. Compounds 3 and 4 were found to be prolyl endopeptidase inhibitors with IC(50) 8.21 +/- 0.407 and 39.63 +/- 1.502 microM, respectively, while compounds 5-7 were found to be acetyl-cholinesterase and butyryl-cholinesterase inhibitors with IC(50) 62.46 +/- 1.58, 153.31 +/- 1.9, 74.5 +/- 1.05 and 150.04 +/- 0.45, 12.99 +/- 0.31, 78.3 +/- 1.86 microM, respectively.     

A new structural theme in the imidazole-containing alkaloids from a calcareous Leucetta sponge

Further study of the Fijian sponge Leucetta sp., a source of (+)-calcaridine A (4) and (-)-spirocalcaridines A (5) and B (6), has yielded (-)-spiroleucettadine (8), the first natural product to contain a fused 2-aminoimidazole oxalane ring along with the known compounds N,N-dimethylnaamidine D (3) and isonaamine B (7). NMR analysis allowed the unambiguous 2D structural assignment of 8, and its relative stereochemistry was determined by ROESY data. Good antibacterial activity was observed for 8 against Enterococcus durans with an MIC of less than 6.25 microg/mL.     

Antimicrobial chemical constituents from the endophytic fungus Phomopsis sp. from Notobasis syriaca

Phomosine K (1), a new phomosine derivative, has been isolated from Phomopsis sp., in addition to six known compounds: phomosine A (2), phenylalanine amide (3), 2-hydroxymethyl-4beta,5alpha,6beta-trihydroxycyclohex-2-en (4), (-)-phyllostine (5), (+)-epiepoxydon (6), and (+)-epoxydon monoacetate (7). Preliminary studies showed that compound 1 had strong antibacterial activity, while compounds 4-7 showed good antifungal, antibacterial, and algicidal properties, except compounds 4 and 6, which lacked antifungal activity.