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Journal of Natural Products

Tomasz Laskowski, Katarzyna Szwarc, Paweł Szczeblewski, Paweł Sowiński, Edward Borowski, Jan Pawlak
Herein, a new method for the elucidation of the absolute configuration of chiral secondary alcohols is proposed. This method is an alternative for a widely used approach reported by Mosher and Dale and similar methods that are based on the (1)H NMR shift (δ) changes of protons that are attached to the substituents of the oxymethine carbon atom. The presented method is not based on tracking the chemical shift changes and utilizes stereochemically defined monosaccharides as chiral probes. A secondary alcohol is glycosylated, and the resulting glycoside is subjected to NMR studies...
October 26, 2016: Journal of Natural Products
Yuki Hitora, Kentaro Takada, Yuji Ise, Shigeru Okada, Shigeki Matsunaga
LCMS analysis of the extract and a cytotoxicity assay of the HPLC fractions generated from a small-scale extract of a Lipastrotethya sp. marine sponge demonstrated the presence of bisindole alkaloids that were associated with the cytotoxic activity. Two bisindole alkaloids tethered by a guanidino ethylthiopyrazine moiety, dragmacidins G (1) and H (2), were isolated, and their structures were assigned by analysis of the MS and NMR data. They showed moderate cytotoxic activity against HeLa cells.
October 25, 2016: Journal of Natural Products
Choy-Eng Nge, Kae-Shin Sim, Siew-Huah Lim, Noel F Thomas, Yun-Yee Low, Toh-Seok Kam
Examination of the EtOH extract of the Malayan Tabernaemontana corymbosa resulted in the isolation of three new alkaloids, viz., cononuridine (1), an unusual hexacyclic, iboga-derived, monoterpenoid indole characterized by contraction of the tetrahydroazepine C-ring and incorporation of an additional isoxazolidine ring, taberisidine (2), a seco-corynanthean alkaloid, and conofolidine (3), an Aspidosperma-Aspidosperma bisindole that showed pronounced in vitro growth inhibitory activity against an array of human cancer cell lines, including KB, vincristine-resistant KB, PC-3, LNCaP, MCF7, MDA-MB-231, HT-29, and HCT 116 cells...
October 19, 2016: Journal of Natural Products
Yu-Ming Hsu, Fang-Rong Chang, I-Wen Lo, Kuei-Hung Lai, Mohamed El-Shazly, Tung-Ying Wu, Ying-Chi Du, Tsong-Long Hwang, Yuan-Bin Cheng, Yang-Chang Wu
Zoanthus kuroshio is a colorful zoanthid with a fluorescent pink oral disc and brown tentacles, which dominates certain parts of the Taiwanese and Japanese coasts. This sea anemone is a rich source of biologically active alkaloids. In the current investigation, two novel halogenated zoanthamines [5α-iodozoanthenamine (1) and 11β-chloro-11-deoxykuroshine A (2)], along with four new zoanthamines [18-epi-kuroshine A (3), 7α-hydroxykuroshine E (4), 5α-methoxykuroshine E (5), and 18-epi-kuroshine E (6)], and six known compounds were isolated from Z...
October 19, 2016: Journal of Natural Products
Tao Jiang, Menghua Wang, Li Li, Jinguang Si, Bo Song, Cao Zhou, Meng Yu, Xuewei Wang, Yonggang Zhang, Gang Ding, Zhongmei Zou
Overexpression of laeA in Chaetomium globosum CBS148.51 up-regulated expression of the chaetoglobosin gene cluster and resulted in the isolation of a new cytochalasan, chaetoglobosin Z (1), together with six known analogues, chaetoglobosins A (2), B (3), D (4), E (5), O (6), and V (7). RT-PCR analysis confirmed that the key genes in the chaetoglobosin gene cluster were significantly up-regulated. The structure of the new compound chaetoglobosin Z (1) was elucidated using NMR data. The relative and absolute configurations were determined by NOESY and electronic circular dichroism combined with quantum-chemical calculations adopting time-dependent density functional theory methods, respectively...
October 19, 2016: Journal of Natural Products
Narayan D Chaurasiya, Vedanjali Gogineni, Khaled M Elokely, Francisco León, Marvin J Núñez, Michael L Klein, Larry A Walker, Stephen J Cutler, Babu L Tekwani
Calea urticifolia (Asteraceae: Asteroideae) has long been used as a traditional medicine in El Salvador to treat arthritis and fever, among other illnesses. The chloroform extract of the leaves of C. urticifolia showed potent inhibition of recombinant human monoamine oxidases (MAO-A and -B). Further bioassay-guided fractionation led to the isolation of a flavonoid, acacetin, as the most prominent MAO inhibitory constituent, with IC50 values of 121 and 49 nM for MAO-A and -B, respectively. The potency of MAO inhibition by acacetin was >5-fold higher for MAO-A (0...
October 18, 2016: Journal of Natural Products
Brian Guo, Monday M Onakpa, Xiao-Jun Huang, Bernard D Santarsiero, Wei-Lun Chen, Ming Zhao, Xiao-Qi Zhang, Steven M Swanson, Joanna E Burdette, Chun-Tao Che
No abstract text is available yet for this article.
October 17, 2016: Journal of Natural Products
Shi-Jun Yue, Cheng Qu, Peng-Xuan Zhang, Yu-Ping Tang, Yi Jin, Jian-Shuang Jiang, Ya-Nan Yang, Pei-Cheng Zhang, Jin-Ao Duan
Two novel quinochalcone C-glycosides, carthorquinosides A (1) and B (2), were isolated from the florets of Carthamus tinctorius. Their structures, including the absolute configurations, were established by analysis of NMR and MS data, together with chemical degradation and electronic circular dichroism spectra. Compound 1 has an unprecedented quinochalcone-flavonol structure linked via a methylene bridge, and compound 2 comprises two glucopyranosylquinochalcone moieties linked via the formyl carbon of an acyclic glucosyl unit...
October 17, 2016: Journal of Natural Products
Wenlong Cai, Xiachang Wang, Sherif I Elshahawi, Larissa V Ponomareva, Xiaodong Liu, Matthew R McErlean, Zheng Cui, Ashley L Arlinghaus, Jon S Thorson, Steven G Van Lanen
Four new Y-type actinomycin analogues named Y6-Y9 (1-4) were isolated and characterized from the scale-up fermentation of the Streptomyces sp. strain Gö-GS12, as well as actinomycin Zp (5), which was, for the first time, isolated as a natural product. Structures of the new compounds were elucidated by the cumulative analyses of NMR spectroscopy and HRMS. The 4-hydroxythreonine on the β-ring of 1 uniquely undergoes both a rearrangement by a 2-fold acyl shift and an additional ring closure with the amino group of the phenoxazinone chromophore, and the α-rings of 4 and 5 contain a rare 5-methyl proline...
October 13, 2016: Journal of Natural Products
Lars Andernach, Louis P Sandjo, Johannes C Liermann, Ricardo Schlämann, Christian Richter, Jan-Peter Ferner, Harald Schwalbe, Anja Schüffler, Eckhard Thines, Till Opatz
Three secondary fungal metabolites 1-3 with a benzo[b]naphtho[2,1-d]furan skeleton were isolated from submerged cultures of the ascomycete Allantophomopsis lycopodina. The NMR-based structure elucidation was challenging due to a low H/C ratio of only 0.64 and 0.68, respectively. NMR measurements in two different solvents and the use of NMR experiments such as HSQC-TOCSY and LR-HSQMBC proved to be helpful in this respect. The proposed structures obtained from the comprehensive analysis of the NMR data were verified by comparison of recorded and computed NMR chemical shifts from quantum chemical calculations of several constitutional isomers and were further analyzed with the aid of the DP4 and DP4+ probabilities...
October 12, 2016: Journal of Natural Products
Ling Liu, Yu Han, Junhai Xiao, Li Li, Liangdong Guo, Xuejun Jiang, Lingyi Kong, Yongsheng Che
Chlorotheolides A (1) and B (2), two new spiroketals possessing the unique [4,7]methanochromene and dispiro-trione skeletons, respectively, and their putative biosynthetic precursors, 1-undecen-2,3-dicarboxylic acid (3) and maldoxin (4), were isolated from the solid substrate fermentation of the plant endophytic fungus Pestalotiopsis theae (N635). Their structures were elucidated based on NMR spectroscopic data and electronic circular dichroism calculations. Biogenetically, compounds 1 and 2 could be generated from the co-isolated 3 and 4 via Diels-Alder reactions...
October 12, 2016: Journal of Natural Products
Muthiah Suresh, Navin Kumar, Gorre Veeraraghavaiah, Sunit Hazra, Raj Bahadur Singh
The first synthesis of coprinol has been achieved from 2-methoxy-3,5-dimethylbenzaldehyde via the intermediacy of an indanone derivative where dialkylation, Friedel-Crafts acylation, demethylation, and regioselective formation of a primary -OH group from a chloroacetyl group are the key steps.
October 12, 2016: Journal of Natural Products
Ju-Ying Tsai, Dóra Rédei, Peter Forgo, Yu Li, Andrea Vasas, Judit Hohmann, Chin-Chung Wu
Human platelets contain conventional (α and β) and novel isoforms of PKC (δ and θ), and PKC activation can result in platelet aggregation and secretion reaction that are important for thrombus formation. Several tumor-promoting Euphorbiaceae diterpenes are known to act as direct activators of PKC, but many types of such diterpenes have not been studied as platelet stimulators. In the present study, two new and five known phorbol esters were isolated from Euphorbia grandicornis. Two of the isolated phorbol esters together with compounds representing ingenane, jatrophane, and myrsinane structural types were studied on PKC activation and platelet stimulation...
October 12, 2016: Journal of Natural Products
Jong Won Kim, Sung-Kyun Ko, Hye-Min Kim, Gun-Hee Kim, Sangkeun Son, Gil Soo Kim, Gwi Ja Hwang, Eun Soo Jeon, Kee-Sun Shin, In-Ja Ryoo, Young-Soo Hong, Hyuncheol Oh, Kyung Ho Lee, Nak-Kyun Soung, Daisuke Hashizume, Toshihiko Nogawa, Shunji Takahashi, Bo Yeon Kim, Hiroyuki Osada, Jae-Hyuk Jang, Jong Seog Ahn
Two new phenylspirodrimane derivatives, stachybotrysin (1) and stachybotrylactone B (2), were isolated from the cultures of the marine-derived fungus Stachybotrys sp. KCB13F013. The structures were determined by analyzing the spectroscopic data (1D and 2D NMR and MS) and chemical transformation, including the modified Mosher's method and single-crystal X-ray structure analysis. Compound 1 exhibited an inhibitory effect on osteoclast differentiation in bone marrow macrophage cells via suppressing the RANKL-induced activation of p-ERK, p-JNK, p-p38, c-Fos, and NFATc1...
October 11, 2016: Journal of Natural Products
Nicolas Gaboriaud-Kolar, Vasillios Myrianthopoulos, Konstantina Vougogiannopoulou, Panagiotis Gerolymatos, David A Horne, Richard Jove, Emmanuel Mikros, Sangkil Nam, Alexios-Leandros Skaltsounis
Drug resistance in chronic myelogenous leukemia (CML) requires the development of new CML chemotherapeutic drugs. Indirubin, a well-known mutikinase inhibitor, is the major active component of "Danggui Longhui Wan", a Chinese traditional medicine used for the treatment of CML symptoms. An in-house collection of indirubin derivatives was screened at 1 μM on wild-type and imatinib-resistant T315I mutant CML cells. Herein are reported that only 15 analogues of the natural 6-bromoindirubin displayed potent cytotoxicity in the submicromolar range...
October 11, 2016: Journal of Natural Products
Julio C Pardo-Novoa, Héctor M Arreaga-González, Mario A Gómez-Hurtado, Gabriela Rodríguez-García, Carlos M Cerda-García-Rojas, Pedro Joseph-Nathan, Rosa E Del Río
The aerial parts of Ageratina glabrata afforded (-)-(3S,4R,5R,6S)-3,5,6-trihydroxy-1-menthene 3-O-β-d-glucopyranoside (1) and (-)-(3S,4S,6R)-3,6-dihydroxy-1-menthene 3-O-β-d-glucopyranoside (3). Acid hydrolysis of 1 yielded (+)-(1R,4S,5R,6R)-1,5,6-trihydroxy-2-menthene (5) and (+)-(1S,4S,5R,6R)-1,5,6-trihydroxy-2-menthene (6), while hydrolysis of 3 yielded (+)-(3S,4S,6R)-3,6-dihydroxy-1-menthene (10), (+)-(1R,4S,6R)-1,6-dihydroxy-2-menthene (11), and (+)-(1S,4S,6R)-1,6-dihydroxy-2-menthene (12). The structures of the new compounds 1, 2, 5-9, and 11 were defined by 1D and 2D NMR experiments, while the absolute configurations of the series of compounds were determined by comparison of the experimental vibrational circular dichroism (VCD) spectra of the 1,6-acetonide 5-acetate derived from 6 and of the 1,6-acetonide derived from 12 with their DFT-calculated spectra...
October 11, 2016: Journal of Natural Products
Cody L Covington, Fernando M S Junior, Jessica H S Silva, Ricardo M Kuster, Mauro B de Amorim, Prasad L Polavarapu
The first natural occurrence in optically active form of the dimeric flavonoid agathisflavone and definition of its axial chirality using chiroptical spectroscopic methods are described. The experimental electronic circular dichroism, electronic dissymmetry factor, optical rotatory dispersion, vibrational circular dichroism (VCD), and vibrational dissymmetry factor spectra of agathisflavone are presented and analyzed with their corresponding quantum chemical predictions to definitively assign the axial chirality of (-)-agathisflavone as (aS)...
October 10, 2016: Journal of Natural Products
Cathryn A Slabber, Craig D Grimmer, Ross S Robinson
NAMFIS (NMR Analysis of Molecular Flexibility In Solution) has been applied to curcumin dissolved in DMSO. Quantitative (1)H-(1)H distance constraints reduce a pool of candidate conformations to a solution collection of four enol conformations-two of these match curcumin crystallized with human transthyretin, and one is closely related to a single-crystal structure of curcumin.
October 7, 2016: Journal of Natural Products
Chun-Tang Chiou, Chien-Chang Shen, Tung-Hu Tsai, Yu-Jen Chen, Lie-Chwen Lin
Six new meroterpenoids, diplomeroterpenoids A-F (1-6), two new chalcone-lignoids, diplochalcolins A and B (7, 8), and 13 known compounds were isolated from the root extract of Mimosa diplotricha. Diplomeroterpenoids A-F consist of a 4H-chromen-4-one and a diterpenoid unit, and their absolute configurations were determined by X-ray crystallographic analysis. Compounds 1-3 and 5 showed potent inhibitory activity on protein farnesyl transferase, with IC50 values from 5.0 to 8.5 μM. Compound 1 showed antiproliferative activity against human hepatoblastoma HepG2 cells with a GI50 value of approximately 8...
October 7, 2016: Journal of Natural Products
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