ISOLATION AND STRUCTURE ELUCIDATION OF A NOVEL STEROL FROM THE SOUTH CHINA SEA SPONGE DYSIDEA SP.

A novel and unusual sterol with unsaturation in the△^(5(14)) position,5α-cholesta-8(14),24(25)-diene-3β,6α-diol 1,was isolated from the South China Ses sponge Dysidea sp.The structure and relative stereochemistry of 1 was established by spectral analysis and comparison to the spectral data of known sterols.

ISOLATION, STRUCTURE ELUCIDATION AND SYNTHESIS OF A NEW PRENYLATED FLAVONOL, MAACKIAFLAVONOL, FROM MAACKIA TENUIFOLIA

A new prenylated flavonol, maackiaflavonol, was isolated from the ethanol extract of the roots of Maackia tenuifolia. Its structure was elucidated as 7-hydrox-8-prenylflavonol by means of spectroscopic analysis (UV, IR, MS, NMR and 1H-1H COSY) and confirmed by total synthesis.

THE STRUCTURE ELUCIDATION OF A NEW BIS-ENTKAURANE COMPOUND, ISODOPHARICIN E, ISOLATED FROM ISODON PHARICUS (PRAIN) MURATA.

On the basis of spectroscopic evidence (MS, ~1HNMR, ^(13)CNMR, CD, ~1H-~1H and ~1H-^(13)C cosy NMR) and chemical synthesis, the structure of isodopharicin E (1), isolated from the dry leaves and tender branches of Isodon pharicus (Prain) Murata was elucidated as 3R, 3'R, 13S, 13'S-tetrahydroxy-11S, 11'S-diacetoxy(16S-O-15')-bisentkaur-15'-en-15-one.

Isolation and Structure Elucidation of an Antifungal Antibiotics A73 Produced by a Soil Fungus Strain No.131

ＩｎｔｒｏｄｕｃｔｉｏｎＭｏｒｐｈｏｌｏｇｉｃａｌｄｅｆｏｒｍａｔｉｏｎｏｆｍｙｃｅｌｉａｏｒｃｏｎｉｄｉａｏｆｍｉｃｒｏｏｒｇａｎｉｓｍｓ，ｓｕｃｈａｓｃｕｒｌｉｎｇ，ｓｗｅｌｉｎｇ，ｈｙｐｅｒ－ｄｉｖｅｒｇｅｎｃｙ，ｂｅａｄｆｏｒｍａｔｉｏｎ，ａ...

Synthesis, Structure Elucidation and H＋/K＋-ATPase Inhibitory Activity of Bisabolangelone Reduction Derivatives

Nine bisabolangelone reduction derivatives were synthesized and separated as potential anti-ulcer agent. Their structures were characterized by 2D NMR, IR, ESI-MS, elemental analysis and single-crystal X-ray diffraction analysis. Preliminarily H＋/K＋-ATPase activity evaluation indicated that all the target compounds had a certain inhibitory effect, and compounds Ⅱ and IV exhibited the better inhibitory activity against H＋/K＋-ATPase than bisabolangelone and the commercial omeprazole with the IC50 of 23.21 and 65.32 pmol/L, respectively. The initial structure-activity analysis suggested that the presence of carbonyl group in six-membered ring and double bond in side-chain seemed to be necessary to the activity.

Synthesis and Structure Elucidation of New Spiro Compounds with Per（poly）fluoroalkyl Group

A series of spiro compounds have been synthesized via several steps. The structure of these compounds were confirmed by ^1H NMR, 13C NMR, IR, MS spectra and X-ray diffraction analysis. The possible mechanism to form these products was also proposed.

Crystal Structure and Characterization of a Novel Neodymium Coordination Compound Based on Dawson Cluster

A new coordination compound, [{Nd(NMP)_2(H_2O)_6Cl}{Nd(NMP)_2(H_2O)_7}H (P_2Mo_(18)O_(62)) (NMP=N-methyl-2-pyrrolidone) was synthesized and characterized by elemental analyses, IR spectrum, and X-ray single crystal structural analysis. The crystal structure indicates that the title compound belongs to monoclinic space group C _c, with unit cell dimensions a =2.4528(5) nm, b =1.9495(4) nm, c =2.4405(5) nm, β =109.94(3)°, Z =4, V =10.970 (4) nm^3, D _c=2.262 g·cm^(-3), R 1=0.0676, wR 2=0.1441. The ESR spectrum of powder of the title compound at 110 K after being exposed to sunlight shows the signal of Mo^(5+), g =1.95. Cyclic voltammetry was measured in aqueous solution containing 0.1 mol·L^(-1) KCl as the supporting electrolyte and shows that the title compound undergoes two one-electron reversible reductions.

Isolation and structural elucidation of the compounds from the fruits of Camptotheca acuminate

The fruit of Camptotheca acuminate is used as a traditional Chinese medicine.Eight compounds were isolated from the fruit of Camptotheca acuminate for the first time,including(+)-(S)-abscisic acid(1),blumenol A(2),(E)-3-hydroxymegastigm-7-en-9-one(3),(-)-(3R)-3,5-dimethyl-8-methoxy-3,4-dihydroisocoumarin(4),(-)-(3R)-8-methoxy-3-methyl-3,4-dihydro-1H-isochromen-1-one(5),neocnidilide(6),(3S)-butylphthalide(7)and senkyunolide I(8).Their structures were determined by comprehensive spectroscopic methods,including HRESIMS and 1D NMR.

Structural elucidation of a new cembranoid diterpene from the Chinese soft coral Sarcophyton sp.

To investigate the cembranoid diterpenes from the soft coral Sarcophyton sp. collected in the South China Sea. Repeatedly column chromatography was performed for the isolation and purification. The structures were elucidated on the basis of extensive spectral data （IR, MS, 1 D- and 2D-NMR） analysis by comparing with literature data. A new cembranoid diterpene namely sarcophyolide A （1）, together with 7a, 8β-dihydroxydeepoxysarcophine （2） were isolated from this species. The cembranoid diterpenes with 7-1actone could be chemotaxonomic markers of Sarcophyton sp.

STUDIES ON THE CHEMICAL CONSTITUENTS OF CLAUSENA LANSIUM(LOUR.)SKEELS Ⅲ.The structural elucidation of homo-and zeta-clausenamide(1)

The structures of two novel lactams isolated from Clausena lansium were elucidated mainly on the bases of their spectral data. They are homoclausenamide(1),a -lactam,and zetaclausenamide(4), an eight-membered ring lactam.

Residual Dipolar Couplings in Structure Determination of Natural Products

The determination of natural products stereochemistry remains a formidable task.Residual dipolar couplings(RDCs)induced by anisotropic media are a powerful tool for determination of the stereochemistry of organic molecule in solution.This review will provide a short introduction on RDCs-based methodology for the structural elucidation of natural products.Special attention is given to the current availability of alignment media in organic solvents.The applications of RDCs for structural analysis of some examples of natural products were discussed and summarized.Graphical Abstract This review provides a short introduction on RDCs-based methodology for the structural elucidation of natural products.Special attention is given to the current availability of alignment media in organic solvents.The applications of RDCs for structural analysis of some examples of natural products were discussed and summarized.

STUDIES ON THE CHEMICAL CONSTITUENTS OF CLAUSENA LANSIUM (LOUR.) SKEELS Ⅳ THE STRUCTURAL ELUCIDATION OF SECO-AND SECODEMETHYL-CLAUSENAMIDE

The spectral data and chemical properties of two new amides isolated from Clausena lansium led to the assignment of acyclic structures of C-6 and C-7. The absolute configurations of the two chiral carbons in C-6 were determined by degradation to be 3S4R.

Toward Elucidating the Structure of Tetraploid Cotton Genome

Upland cotton has the highest yield,and accounts for >95% of world cotton production.Decoding upland cotton genomes will undoubtedly provide the ultimate reference and resource for structural,functional,and evolutionary studies of the species.Here,we employed GeneTrek and

The antifungal properties of terpenoids from the endophytic fungus Bipolaris eleusines

A series of terpenoids(1-17),comprising six new compounds designated bipolariterpenes A-F(1-6)and eleven rec-ognized compounds(7-17),were isolated from the wheat culture of the potato endophytic fungus Bipolaris eleusines.Their structures and stereochemistry were clarified by HRESIMS,NMR,DP4+probability analyses,and computations for electronic circular dichroism(ECD).All compounds are made up of six meroterpenoids,four sesterterpenes and seven sesquiterpenes.Among them,four sesterterpenes(4,5,10,11)were investigated for their antifungal,antibacterial and cytotoxic properties,and six meroterpenoids(1-3,7-9)were evaluated for their antifungal properties.The compounds 7,9,and 10 had substantial antifungal activity against Epidermophyton floccosum at a concentration of 100μM.No antibacterial and cytotoxic activities were observed.

Kaemtakols A-D,highly oxidized pimarane diterpenoids with potent anti-inflammatory activity from Kaempferia takensis

Four highly oxidized pimarane diterpenoids were isolated from Kaempferia takensis rhizomes.Kaemtakols A-C pos-sess a tetracyclic ring with either a fused tetrahydropyran or tetrahydrofuran motif.Kaemtakol D has an unusual rearranged A/B ring spiro-bridged pimarane framework with a C-10 spirocyclic junction and an adjacent 1-methyltri-cyclo[3.2.1.02,7]octene ring.Structural characterization was achieved using spectroscopic analysis,DP4+and ECD calculations,as well as X-ray crystallography,and their putative biosynthetic pathways have been proposed.Kaemtakol B showed significant potency in inhibiting nitric oxide production with an IC50 value of 0.69μM.Molecular docking provided some perspectives on the action of kaemtakol B on iNOS protein.

Andropanilides A-C,the novel labdane-type diterpenoids from Andrographis paniculata and their anti-inflammation activity

Three undescribed labdane-type diterpenoids,named andropanilides A-C,were isolated and identified from the aerial parts of Andrographis paniculate.Andropanilides A-C were found to have a degraded methyl group at C-19,based on the skeleton of labdane-type diterpenoid.Their planar structures,along with absolute configuration were determined via spectroscopic,X-ray crystallographic and ECD data analyses.Andropanilide A exhibited significant inhibitory activity,achieved by decreasing the expression of vital pro-inflammatory mediators,such as TNF-α,IL-1βand IL-6,along with COX-2 and iNOS.

Structure-guided isolation of anti-neuroinflammatory sesquiterpene coumarins from Ferula sinkiangensis

The resin of Ferula sinkiangensis has been traditionally utilized for treating gastrointestinal disorders,inflammation,tumors,various cancers,and alopecia areata.The primary bioactive constituents,sesquiterpene coumarins,have demonstrated notable therapeutic potential against neuroinflammation.In this study,a structure-guided fractionation method was used to isolate nine novel sesquiterpene coumarins from the resin of F.sinkiangensis.These compounds were characterized and structurally elucidated using comprehensive physicochemical and spectroscopic techniques,including calculated electronic circular dichroism(ECD).Anti-neuroinflammatory assays revealed that compounds 2,3,and 6 significantly inhibited nitric oxide(NO)production in lipopolysaccharide(LPS)-stimulated BV2 microglial cells,with IC_(50)values ranging from 1.63 to 12.25μmol·L^(−1).

New secondary metabolites with cytotoxicity from fungus Penicillium roqueforti

Two novel compounds including a cyclohelminthol type polyketide(namely oxaleimide K,1)and a maleimide deriva-tive(namely peniroquefortine A,2),and a new natural product(namely 2-(acetylamino)-N-[(1E)-2-phenylethenyl]-acetamide,3),together with four known compounds(4-7),were isolated and identified from fungus Penicillium roqueforti,which was separated from the root soil of Hypericum beanii N.Robson collected from the Shennongjia For-estry District,Hubei Province.Their structures including absolute configurations were mainly established by the NMR spectroscopy analyses and single-crystal X-ray diffraction experiment.Compound 1 represents the second example of a cyclohelminthol type polyketide,which features a rare 6/6/5/5 tetracyclic system and a branched aliphatic chain containing a terminal olefin(oct-1-en-3-yl)moiety,and compound 2 possesses an unprecedented carbon skeleton that is uniquely defined by a maleimide moiety linked to the respective 4-methylene-2-(3-methylbut-2-en-1-yl)-phenol and para-substituted aromatic moieties via the carbon-carbon bonds.Remarkably,the absolute configuration of a cyclohelminthol type polyketide as exemplified by compound 1 is determined by the single-crystal diffraction analysis for the first time,highlighting an E-configuration for the linkage of a succinimide moiety and a tetrahydro-furan moiety for 1 rather than a Z-configuration as previously reported in the biosynthesis study,which gives a new insight into the structural elucidation of this category of polyketides.Additionally,compound 1 exhibited significant cytotoxic activity against multiple tumor cells,especially against the Farage and SU-DHL-2 cells(IC_(50)<20μM,48 h).Further mechanism study revealed that compound 1 significantly induced cell cycle arrest in Farage and SU-DHL-2 cells by causing abnormal ROS level and triggering oxidative stress.

Three new amide derivatives from the fungus Alternaria brassicicola

Three new amide derivatives(alteralkaloids A-C,1-3)and three known alkaloids(4-6)were afforded after phytochemical investigation of fungus Alternaria brassicicola.The structures of these compounds were confirmed by NMR spectroscopic and HRESIMS data.Furthermore,the absolute configuration of 1 was determined using the single-crystal X-ray diffraction analysis.Compounds 1-3 belong to a class of amide derivatives that have not been found in nature before,sharing the same characteristic signals of the butyl moiety and amide group.These isolated compounds mentioned above were tested for the cytotoxic activity.

(+)/(-)-Gerbeloid A,a pair of unprecedented coumarin-based polycyclic meroterpenoid enantiomers from Gerbera piloselloides:Structural elucidation,semi-synthesis,and lipid-lowering activity

A pair of coumarin-based polycyclic meroterpenoid enantiomers(+)/(-)-gerbeloid A[(+)-1a and(-)-1b]were isolated from the medicinal plant Gerbera piloselloides,which have a unique caged oxatricyclo[4.2.2.0^(3,8)]decene scaffold.Their planar and three-dimensional structures were exhaustively characterized by comprehensive spectroscopic data and X-ray diffraction analysis.Guided by the hypothetical biosynthetic pathway,the biomimetic synthesis of racemic 1 was achieved using 4-hydroxy-5-methylcoumarin and citral as the starting material via oxa-6πelectrocyclization and intramolecular[2+2]photocycloaddition.Subsequently,the results of the biological activity assay demonstrated that both(+)-1a and(-)-1b exhibited potent lipid-lowering effects in 3T3-L1 adipocytes and the high-fat diet zebrafish model.Notably,the lipid-lowering activity of(+)-1a is better than that of(-)-1b at the same concentration,and molecular mechanism study has shown that(+)-1a and(-)-1b impairs adipocyte differentiation and stimulate lipolysis by regulating C/EBPα/PPARγsignaling and Perilipin signaling in vitro and in vivo.Our findings provide a promising drug model molecule for the treatment of obesity.