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Can Small Chemical Modifications of Natural Pan-inhibitors Modulate the Biological Selectivity? The Case of Curcumin Prenylated Derivatives Acting as HDAC or mPGES-1 Inhibitors
Mehrdad Iranshahi - ,
Maria Giovanna Chini - ,
Milena Masullo - ,
Amirhossein Sahebkar - ,
Azita Javidnia - ,
Mahsa Chitsazian Yazdi - ,
Carlo Pergola - ,
Andreas Koeberle - ,
Oliver Werz - ,
Cosimo Pizza - ,
Stefania Terracciano - ,
Sonia Piacente *- , and
Giuseppe Bifulco *
Curcumin, or diferuloylmethane, a polyphenolic molecule isolated from the rhizome of Curcuma longa, is reported to modulate multiple molecular targets involved in cancer and inflammatory processes. On the basis of its pan-inhibitory characteristics, here we show that simple chemical modifications of the curcumin scaffold can regulate its biological selectivity. In particular, the curcumin scaffold was modified with three types of substituents at positions C-1, C-8, and/or C-8′ [C5 (isopentenyl, 5–8), C10 (geranyl, 9–12), and C15 (farnesyl, 13, 14)] in order to make these molecules more selective than the parent compound toward two specific targets: histone deacetylase (HDAC) and microsomal prostaglandin E2 synthase-1 (mPGES-1). From combined in silico and in vitro analyses, three selective inhibitors by proper substitution at position 8 were revealed. Compound 13 has improved HDAC inhibitory activity and selectivity with respect to the parent compound, while 5 and 9 block the mPGES-1 enzyme. We hypothesize about the covalent interaction of curcumin, 5, and 9 with the mPGES-1 binding site.

11-Hydroxylation of Protoberberine by the Novel Berberine-Utilizing Aerobic Bacterium Sphingobium sp. Strain BD3100
Hisashi Takeda - ,
Kazuki Ishikawa - ,
Daigo Wakana - ,
Masao Fukuda - ,
Fumihiko Sato - , and
Tomoo Hosoe *
Protoberberine alkaloids, including berberine, palmatine, and berberrubine, are produced by medicinal plants and are known to have various pharmacological effects. We isolated two berberine-utilizing bacteria, Sphingobium sp. strain BD3100 and Rhodococcus sp. strain BD7100, from soil collected at a natural medicine factory. BD3100 had the unique ability to utilize berberine or palmatine as the sole carbon and energy source. BD3100 produced demethyleneberberine in berberine-supplemented medium. In a resting-cell incubation with berberine, BD3100 produced 11-hydroxyberberine; the structure of 11-hydroxyberberine was determined by detailed analysis of NMR and MS spectroscopic data. α-Naphthoflavone, miconazole, and ketoconazole, which are known inhibitors of cytochrome P450, interfered with BD3100 metabolism of berberine in resting cells. Inhibition by miconazole led to the production of a new compound, 11-hydroxydemethyleneberberine. In a resting-cell incubation with palmatine, BD3100 generated 11-hydroxypalmatine. This work represents the first report of the isolation and characterization of novel berberine-utilizing aerobic bacteria for the production of 11-hydroxylation derivatives of berberine and palmatine.

Antinociceptive Grayanoids from the Roots of Rhododendron molle
Yong Li - ,
Yun-Bao Liu - ,
Jian-Jun Zhang - ,
Yang Liu - ,
Shuang-Gang Ma - ,
Jing Qu - ,
Hai-Ning Lv - , and
Shi-Shan Yu *
Nine new grayanoids (1–9), together with 11 known compounds, were isolated from the roots of Rhododendron molle. The structures of the new compounds (1–9) were determined on the basis of spectroscopic analysis, including HRESIMS, and 1D and 2D NMR data. Compounds 4, 6, 12, and 14–20 showed significant antinociceptive activities in an acetic acid-induced writhing test. In particular, 14 and 15 were found to be more potent than morphine for both acute and inflammatory pain models and 100-fold more potent than gabapentin in a diabetic neuropathic pain model.

DFT Calculations and ROESY NMR Data for the Diastereochemical Characterization of Cytotoxic Tetraterpenoids from the Oleoresin of Abies balsamea
Serge Lavoie - ,
Charles Gauthier - ,
Vakhtang Mshvildadze - ,
Jean Legault - ,
Benoit Roger - , and
André Pichette *
Eight non-carotenoid tetraterpenoids, abibalsamins C–J (3–10), were isolated from the oleoresin of Abies balsamea. Their chemical structures were determined based on analysis of 1D/2D NMR and MS data. The assignment of their relative configurations was accomplished using homonuclear coupling constants in tandem with ROESY data. However, the presence of two stereogenic centers on a flexible side chain complicated the characterization. In silico models and ROESY data were analyzed in order to assign relative configurations of the isolated tetraterpenoids. Abibalsamins B and H–J showed moderate cytotoxicity against human A549 lung carcinoma cells, with IC50 values ranging between 6.7 and 10 μM.

Cytotoxic C20 Diterpenoid Alkaloids from the Australian Endemic Rainforest Plant Anopterus macleayanus
Claire Levrier - ,
Martin C. Sadowski - ,
Colleen C. Nelson - , and
Rohan A. Davis *
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In order to identify new anticancer compounds from nature, a prefractionated library derived from Australian endemic plants was generated and screened against the prostate cancer cell line LNCaP using a metabolic assay. Fractions from the seeds, leaves, and wood of Anopterus macleayanus showed cytotoxic activity and were subsequently investigated using a combination of bioassay-guided fractionation and mass-directed isolation. This led to the identification of four new diterpenoid alkaloids, 6α-acetoxyanopterine (1), 4′-hydroxy-6α-acetoxyanopterine (2), 4′-hydroxyanopterine (3), and 11α-benzoylanopterine (4), along with four known compounds, anopterine (5), 7β-hydroxyanopterine (6), 7β,4′-dihydroxyanopterine (7), and 7β-hydroxy-11α-benzoylanopterine (8); all compounds were purified as their trifluoroacetate salt. The chemical structures of 1–8 were elucidated after analysis of 1D/2D NMR and MS data. Compounds 1–8 were evaluated for cytotoxic activity against a panel of human prostate cancer cells (LNCaP, C4-2B, and DuCaP) and nonmalignant cell lines (BPH-1 and WPMY-1), using a live-cell imaging system and a metabolic assay. All compounds showed potent cytotoxicity with IC50 values of <400 nM; compound 1 was the most active natural product from this series, with an IC50 value of 3.1 nM toward the LNCaP cell line. The live-cell imaging assay on 1–8 showed a concentration- and time-dependent effect on the cell morphology and proliferation of LNCaP cells.

Azaphilones from an Acid Mine Extremophile Strain of a Pleurostomophora sp.
Andrea A. Stierle *- ,
Donald B. Stierle *- ,
Teri Girtsman - ,
T. C. Mou - ,
Christophe Antczak - , and
Hakim Djaballah
An extremophilic fungus identified as a Pleurostomophora sp. was isolated from the Berkeley Pit, an acid mine waste lake. When grown in liquid culture, the fungus produced berkchaetoazaphilones A–C (1, 2, and 5), the red pigment berkchaetorubramine (6), and the known compound 4-(hydroxymethyl)quinoline. These compounds were evaluated as inhibitors of matrix metalloproteinase-3, caspase-1, and proinflammatory cytokine production in induced THP-1 cells. Berkchaetoazaphilone B (2) inhibited IL-1β, TNFα, and IL-6 production in the induced inflammasome assay and was cytotoxic toward human retinoblastoma cell line Y79 (IC50 = 1.1 μM), leukemia cell lines CCRF-CEM and SR, and the melanoma cell line LOX IMVI (IC50 = 10 μM).

Synthesis of the 16S,17S-Epoxyprotectin Intermediate in the Biosynthesis of Protectins by Human Macrophages
Marius Aursnes - ,
Jørn E. Tungen - ,
Romain A. Colas - ,
Iliyan Vlasakov - ,
Jesmond Dalli - ,
Charles N. Serhan *- , and
Trond V. Hansen *
The n-3 polyunsaturated fatty acids act as substrates during the resolution phase of acute inflammation for the biosynthesis of specialized pro-resolving lipid mediators. One premier example is the C22-dihydroxy-polyunsaturated fatty acid protectin D1 (1). The human 15-lipoxygenase type I, via stereoselective processes and with docosahexaenoic acid as the substrate, enables the formation of this specialized pro-resolving lipid mediator. Herein, based on results from LC/MS-MS metabololipidomics, support is presented for the apprehended biosynthesis of 1 in human macrophages occurring via the intermediate 16S,17S-epoxyprotectin (5). Stereochemically pure 5 was obtained using the Katsuki–Sharpless epoxidation protocol, establishing the chirality at the C16 and C17 atoms, one Z-selective reduction, and E- and Z-stereoselective Wittig reactions. In addition, information on the nonenzymatic aqueous hydrolysis products and the half-life of 16S,17S-epoxyprotectin (5) is presented.

Rotenoids, Flavonoids, and Chalcones from the Root Bark of Millettia usaramensis
Tsegaye Deyou - ,
Ivan Gumula - ,
Fangfang Pang - ,
Amra Gruhonjic - ,
Michael Mumo - ,
John Holleran - ,
Sandra Duffy - ,
Paul A. Fitzpatrick - ,
Matthias Heydenreich - ,
Göran Landberg - ,
Solomon Derese - ,
Vicky Avery - ,
Kari Rissanen - ,
Máté Erdélyi *- , and
Abiy Yenesew *
Five new compounds, 4-O-geranylisoliquiritigenin (1), 12-dihydrousararotenoid B (2), 12-dihydrousararotenoid C (3), 4′-O-geranyl-7-hydroxyflavanone (4), and 4′-O-geranyl-7-hydroxydihydroflavanol (5), along with 12 known natural products (6–17) were isolated from the CH2Cl2/MeOH (1:1) extract of the root bark of Millettia usaramensis ssp. usaramensis by chromatographic separation. The purified metabolites were identified by NMR spectroscopic and mass spectrometric analyses, whereas their absolute configurations were established on the basis of chiroptical data and in some cases also by X-ray crystallography. The crude extract was moderately active (IC50 = 11.63 μg/mL) against the ER-negative MDB-MB-231 human breast cancer cell line, and accordingly compounds 6, 8, 9, 10, 12, and 16 also showed moderate to low cytotoxic activities (IC50 25.7–207.2 μM). The new natural product 1 exhibited antiplasmodial activity with IC50 values of 3.7 and 5.3 μM against the chloroquine-sensitive 3D7 and the chloroquine-resistant Dd2 Plasmodium falciparum strains, respectively, and was also cytotoxic to the HEK293 cell line.

Total Synthesis of (±)-Glyceollin II and a Dihydro Derivative
Neha Malik - ,
Zhaoqi Zhang - , and
Paul Erhardt *
Stressed soybeans produce a group of phytoalexins that belong to the 6a-hydroxypterocarpan family of flavonoids. Certain of the more prominent members, such as the glyceollins I, II, and III, have demonstrated potential antidiabetic properties and promising cytotoxicity in both human breast and prostate cancer cell cultures with preliminary studies in animals further demonstrating antitumor effects in estrogen-dependent, human breast cancer cell implants. Although syntheses of glyceollin I have been reported previously, this work constitutes the first total directed synthesis of (±)-glyceollin II. It involves 12 steps with an overall yield of 7% using practical methods that should be readily scalable to produce quantities needed for advanced biological characterization. Highlights include a novel intramolecular benzoin condensation, a chelation-controlled lithium aluminum hydride-mediated reduction, and an intramolecular cyclization via the formation of a transient epoxide intermediate to cap the construction of the 6a-hydroxypterocarpan system. Additionally, a dihydro analogue has been obtained, and several isolated intermediates have been made available for evaluation of their biological properties and possible contributions toward elaborating key structure–activity relationship data among this family of promising phytoalexins elicited from stressed soybeans.

Dihydroisocoumarin Derivatives from Marine-Derived Fungal Isolates and Their Anti-inflammatory Effects in Lipopolysaccharide-Induced BV2 Microglia
Dong-Cheol Kim - ,
Tran Hong Quang - ,
Nguyen Thi Thanh Ngan - ,
Chi-Su Yoon - ,
Jae Hak Sohn - ,
Joung Han Yim - ,
Yu Feng - ,
Yongsheng Che - ,
Youn-Chul Kim *- , and
Hyuncheol Oh *
Chemical investigation of the EtOAc extracts of marine-derived fungal isolates Aspergillus sp. SF-5974 and Aspergillus sp. SF-5976 yielded a new dihydroisocoumarin derivative (1) and 12 known metabolites. The structures of the isolated metabolites were established by extensive spectroscopic analyses, including 1D and 2D NMR spectra and MS data. Among the metabolites, the absolute configuration of 5′-hydroxyasperentin (6) was determined by single-crystal X-ray diffraction analysis. The in vitro antineuroinflammatory effects of the metabolites were also evaluated in lipopolysaccharide (LPS)-stimulated microglial cells. Among the isolated metabolites, dihydroisocoumarin derivatives 1–6 (10–80 μM) were shown to inhibit LPS-induced nitric oxide (NO) and prostaglandin E2 (PGE2) production by suppressing the expression of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2), respectively, in LPS-stimulated BV2 microglia. Further, 1 (20–80 μM) was found to suppress the phosphorylation of the inhibitor of nuclear factor kappa B-α (IκB-α), interrupt the nuclear translocation of nuclear factor kappa B (NF-κB), and decrease the activation of p38 mitogen-activated protein kinase (MAPK).

Effect of Chicoric Acid on Mast Cell-Mediated Allergic Inflammation in Vitro and in Vivo
Na Young Lee - ,
Kyung-Sook Chung - ,
Jong Sik Jin - ,
Keuk Soo Bang - ,
Ye-Jin Eom - ,
Chul-Hee Hong - ,
Agung Nugroho - ,
Hee-Jun Park - , and
Hyo-Jin An *
Chicoric acid (dicaffeoyl-tartaric acid), is a natural phenolic compound found in a number of plants, such as chicory (Cichorium intybus) and Echinacea (Echinacea purpurea), which possesses antioxidant, anti-inflammatory, antiviral, and analgesic activities. Although these biological effects of chicoric acid have been investigated, there are no reports of its antiallergic-related anti-inflammatory effects in human mast cells (HMC)-1 or anaphylactic activity in a mouse model. Therefore, we investigated the antiallergic-related anti-inflammatory effect of chicoric acid and its underlying mechanisms of action using phorbol-12-myristate 13-acetate plus calcium ionophore A23187 (PMACI)-stimulated HMC-1 cells. Chicoric acid decreased the mRNA expression of pro-inflammatory cytokines, such as tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-1β. We studied the inhibitory effects of chicoric acid on the nuclear translocation of nuclear factor kappa B (NF-κB) and activation of caspase-1. However, mitogen-activated protein kinase (MAPK) activation was not sufficient to abrogate the stimulus. In addition, we investigated the ability of chicoric acid to inhibit compound 48/80-induced systemic anaphylaxis in vivo. Oral administration of chicoric acid at 20 mg/kg inhibited histamine release and protected mice against compound 48/80-induced anaphylactic mortality. These results suggest that chicoric acid has an antiallergic-related anti-inflammatory effect that involves modulating mast cell-mediated allergic responses. Therefore, chicoric acid could be an efficacious agent for allergy-related inflammatory disorders.

Bacaryolanes A–C, Rare Bacterial Caryolanes from a Mangrove Endophyte
Ling Ding - ,
Helmar Goerls - ,
Katharina Dornblut - ,
Wenhan Lin - ,
Armin Maier - ,
Heinz-Herbert Fiebig - , and
Christian Hertweck *
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Caryolanes are known as typical plant-derived sesquiterpenes. Here we describe the isolation and full structure elucidation of three caryolanes, bacaryolane A–C (1–3), that are produced by a bacterial endophyte (Streptomyces sp. JMRC:ST027706) of the mangrove plant Bruguiera gymnorrhiza. By 2D NMR, analysis of the first X-ray crystallographic data of a caryolane (bacaryolane C), CD spectroscopy, and comparison with data for plant-derived caryolanes, we rigorously established the absolute configuration of the bacaryolanes and related compounds from bacteria. Bacterial caryolanes appear as the mirror images of typical plant caryolanes. Apparently plant and bacteria harbor stereodivergent biosynthetic pathways, which may be used as metabolic signatures. The discovery of plant-like volatile terpenes in endophytes not only is an important addition to the bacterial terpenome but may also point to complex molecular interactions in the plant–microbe association.

Efficient Determination of the Enantiomeric Purity and Absolute Configuration of Flavanones by Using (S)-3,3′-Dibromo-1,1′-bi-2-naphthol as a Chiral Solvating Agent
Guoxin Du - ,
Yisu Li - ,
Shunan Ma - ,
Rui Wang - ,
Bo Li *- ,
Fujiang Guo *- ,
Weiliang Zhu - , and
Yiming Li *
The enantiomeric purity and absolute configuration of flavanones were first determined using (S)-3,3′-dibromo-1,1′-bi-2-naphthol as a chiral solvating agent by means of 1H NMR spectroscopy. The enantiomeric purity results closely matched those based on chiral HPLC analysis.

Giffonins J–P, Highly Hydroxylated Cyclized Diarylheptanoids from the Leaves of Corylus avellana Cultivar “Tonda di Giffoni”
Milena Masullo - ,
Vincenza Cantone - ,
Antonietta Cerulli - ,
Gianluigi Lauro - ,
Francesco Messano - ,
Gian Luigi Russo - ,
Cosimo Pizza - ,
Giuseppe Bifulco *- , and
Sonia Piacente *
Two new diaryl ether heptanoids, giffonins J and K (1 and 2), along with five new diarylheptanoids, giffonins L–P (3–7), were isolated from a methanol extract of the leaves of Corylus avellana cultivar “Tonda di Giffoni”. These compounds were identified as highly hydroxylated cyclized diarylheptanoids by 1D- and 2D-NMR experiments. The relative configurations of giffonins J–P (1–7) were established by a combined QM (quantum mechanical)/NMR approach, comparing the experimental 13C/1H NMR chemical shift data and the related predicted values. The cytotoxic activities of giffonins J–P (1–7) were evaluated against the human osteosarcoma U2Os and SAOs cell lines.

Antitumor Activity of Americanin A Isolated from the Seeds of Phytolacca americana by Regulating the ATM/ATR Signaling Pathway and the Skp2–p27 Axis in Human Colon Cancer Cells
Cholomi Jung - ,
Ji-Young Hong - ,
Song Yi Bae - ,
Sam Sik Kang - ,
Hyen Joo Park - , and
Sang Kook Lee *
The antiproliferative and antitumor activities of americanin A (1), a neolignan isolated from the seeds of Phytolacca americana, were investigated in human colon cancer cells. Compound 1 inhibited the proliferation of HCT116 human colon cancer cells both in vitro and in vivo. The induction of G2/M cell-cycle arrest by 1 was concomitant with regulation of the ataxia telangiectasia-mutated/ATM and Rad3-related (ATM/ATR) signaling pathway. Treatment with 1 activated ATM and ATR, initiating the subsequent signal transduction cascades that include checkpoint kinase 1 (Chk1), checkpoint kinase 2 (Chk2), and tumor suppressor p53. Another line of evidence underlined the significance of 1 in regulation of the S phase kinase-associated protein 2 (Skp2)–p27 axis. Compound 1 targeted selectively Skp2 for degradation and thereby stabilized p27. Therefore, compound 1 suppressed the activity of cyclin B1 and its partner cell division cycle 2 (cdc2) to prevent entry into mitosis. Furthermore, prolonged treatment with 1 induced apoptosis by producing excessive reactive oxygen species. The intraperitoneal administration of 1 inhibited the growth of HCT116 tumor xenografts in nude mice without any overt toxicity. Modulation of the ATM/ATR signaling pathway and the Skp2–p27 axis might be plausible mechanisms of action for the antiproliferative and antitumor activities of 1 in human colon cancer cells.

Anti-Candida Cassane-Type Diterpenoids from the Root Bark of Swartzia simplex
Quentin Favre-Godal - ,
Stephane Dorsaz - ,
Emerson F. Queiroz *- ,
Laurence Marcourt - ,
Samad N. Ebrahimi - ,
Pierre-Marie Allard - ,
Francine Voinesco - ,
Matthias Hamburger - ,
Mahabir P. Gupta - ,
Katia Gindro - ,
Dominique Sanglard - , and
Jean-Luc Wolfender
A dichloromethane extract of the roots from the Panamanian plant Swartzia simplex exhibited a strong antifungal activity in a bioautography assay against a genetically modified hypersusceptible strain of Candida albicans. At-line HPLC activity based profiling of the crude extract enabled a precise localization of the antifungal compounds, and dereplication by UHPLC-HRESIMS indicated the presence of potentially new metabolites. Transposition of the HPLC reversed-phase analytical conditions to medium-pressure liquid chromatography (MPLC) allowed an efficient isolation of the major constituents. Minor compounds of interest were isolated from the MPLC fractions using semipreparative HPLC. Using this strategy, 14 diterpenes (1–14) were isolated, with seven (5–10, 14) being new antifungal natural products. The new structures were elucidated using NMR spectroscopy and HRESIMS analysis. The absolute configurations of some of the compounds were elucidated by electronic circular dichroism spectroscopy. The antifungal properties of these compounds were evaluated as their minimum inhibitory concentrations in a dilution assay against both hypersusceptible and wild-type strains of C. albicans and by assessment of their antibiofilm activities. The potential cytological effects on the ultrastructure of C. albicans of the antifungal compounds isolated were evaluated on thin sections by transmission electron microscopy.

Stelliosphaerols A and B, Sesquiterpene–Polyol Conjugates from an Ecuadorian Fungal Endophyte
Giovanni C. Forcina - ,
Amaya Castro - ,
Heidi R. Bokesch - ,
Daniel J. Spakowicz - ,
Michelle E. Legaspi - ,
Kaury Kucera - ,
Stephany Villota - ,
Alexandra Narváez-Trujillo - ,
James B. McMahon - ,
Kirk R. Gustafson *- , and
Scott A. Strobel *
Endophytic fungi are plant tissue-associated fungi that represent a rich resource of unexplored biological and chemical diversity. As part of an ongoing effort to characterize Amazon rainforest-derived endophytes, numerous fungi were isolated and cultured from plants collected in the Yasuní National Park in Ecuador. Of these samples, phylogenetic and morphological data revealed a previously undescribed fungus in the order Pleosporales that was cultured from the tropical tree Duroia hirsuta. Extracts from this fungal isolate displayed activity against Staphylococcus aureus and were thus subjected to detailed chemical studies. Two compounds with modest antibacterial activity were isolated, and their structures were elucidated using a combination of NMR spectroscopic analysis, LC-MS studies, and chemical degradation. These efforts led to the identification of stelliosphaerols A (1) and B (2), new sesquiterpene–polyol conjugates that are responsible, at least in part, for the S. aureus inhibitory activity of the fungal extract.

Niizalactams A–C, Multicyclic Macrolactams Isolated from Combined Culture of Streptomyces with Mycolic Acid-Containing Bacterium
Shotaro Hoshino - ,
Masahiro Okada - ,
Toshiyuki Wakimoto - ,
Huiping Zhang - ,
Fumiaki Hayashi - ,
Hiroyasu Onaka - , and
Ikuro Abe *
A terrestrial bacterium, Streptomyces sp. NZ-6, produced niizalactams A–C (1–3), unprecedented di- and tricyclic macrolactams, by coculturing with the mycolic acid-containing bacterium Tsukamurella pulmonis TP-B0596. Their complete structures, including absolute configurations, were elucidated on the basis of spectroscopic data and chemical derivatization. Their unique skeletons are proposed to be biosynthesized from a common 26-membered macrolactam intermediate by SN2 cyclization or an intramolecular Diels–Alder reaction.

Sampangine (a Copyrine Alkaloid) Exerts Biological Activities through Cellular Redox Cycling of Its Quinone and Semiquinone Intermediates
Fakhri Mahdi - ,
J. Brian Morgan - ,
Wenlong Liu - ,
Ameeta K. Agarwal - ,
Mika B. Jekabsons - ,
Yang Liu - ,
Yu-Dong Zhou *- , and
Dale G. Nagle *
The cananga tree alkaloid sampangine (1) has been extensively investigated for its antimicrobial and antitumor potential. Mechanistic studies have linked its biological activities to the reduction of cellular oxygen, the induction of reactive oxygen species (ROS), and alterations in heme biosynthesis. Based on the yeast gene deletion library screening results that indicated mitochondrial gene deletions enhanced the sensitivity to 1, the effects of 1 on cellular respiration were examined. Sampangine increased oxygen consumption rates in both yeast and human tumor cells. Mechanistic investigation indicated that 1 may have a modest uncoupling effect, but predominately acts by increasing oxygen consumption independent of mitochondrial complex IV. Sampangine thus appears to undergo redox cycling that may involve respiratory chain-dependent reduction to a semi-iminoquinone followed by oxidation and consequent superoxide production. Relatively high concentrations of 1 showed significant neurotoxicity in studies conducted with rat cerebellar granule neurons, indicating that sampangine use may be associated with potential neurotoxicity.

Picrajavanicins A–G, Quassinoids from Picrasma javanica Collected in Myanmar
Nwet Nwet Win *- ,
Takuya Ito - ,
Ismail - ,
Takeshi Kodama - ,
Yi Yi Win - ,
Masami Tanaka - ,
Hla Ngwe - ,
Yoshinori Asakawa - ,
Ikuro Abe - , and
Hiroyuki Morita *
Seven new tetracyclic quassinoids, picrajavanicins A–G (1–7), along with three known analogues, were isolated from a CHCl3-soluble extract of the bark of Picrasma javanica collected in Myanmar. The structures of these compounds were elucidated using spectroscopic techniques, including 1D and 2D NMR. The absolute configuration at C-2 of 2 was determined to be S by the modified Mosher method. All the isolates were tested for their antiproliferative activities against a small panel of five human cancer cell lines. However, none of the isolated compounds exhibited inhibitory activity against any of the cancer cells used (IC50 values >10 μM).

Serrulatane Diterpenoid from Eremophila neglecta Exhibits Bacterial Biofilm Dispersion and Inhibits Release of Pro-inflammatory Cytokines from Activated Macrophages
Htwe H. Mon - ,
Susan N. Christo - ,
Chi P. Ndi - ,
Marek Jasieniak - ,
Heather Rickard - ,
John D. Hayball - ,
Hans J. Griesser - , and
Susan J. Semple *
The purpose of this study was to assess the biofilm-removing efficacy and inflammatory activity of a serrulatane diterpenoid, 8-hydroxyserrulat-14-en-19-oic acid (1), isolated from the Australian medicinal plant Eremophila neglecta. Biofilm breakup activity of compound 1 on established Staphylococcus epidermidis and Staphylococcus aureus biofilms was compared to the antiseptic chlorhexidine and antibiotic levofloxacin. In a time-course study, 1 was deposited onto polypropylene mesh to mimic a wound dressing and tested for biofilm removal. The ex-vivo cytotoxicity and effect on lipopolysaccharide-induced pro-inflammatory cytokine release were studied in mouse primary bone-marrow-derived macrophage (BMDM) cells. Compound 1 was effective in dispersing 12 h pre-established biofilms with a 7 log10 reduction of viable bacterial cell counts, but was less active against 24 h biofilms (approximately 2 log10 reduction). Compound-loaded mesh showed dosage-dependent biofilm-removing capability. In addition, compound 1 displayed a significant inhibitory effect on tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) secretion from BMDM cells, but interleukin-1 beta (IL-1β) secretion was not significant. The compound was not cytotoxic to BMDM cells at concentrations effective in removing biofilm and lowering cytokine release. These findings highlight the potential of this serrulatane diterpenoid to be further developed for applications in wound management.

Conformational Analysis of the Host-Defense Peptides Pseudhymenochirin-1Pb and -2Pa and Design of Analogues with Insulin-Releasing Activities and Reduced Toxicities
Giorgia Manzo - ,
Mariano Andrea Scorciapino - ,
Dinesh Srinivasan - ,
Samir Attoub - ,
Maria Luisa Mangoni - ,
Andrea C. Rinaldi - ,
Mariano Casu - ,
Peter R. Flatt - , and
J. Michael Conlon *
Pseudhymenochirin-1Pb (Ps-1Pb; IKIPSFFRNILKKVGKEAVSLIAGALKQS) and pseudhymenochirin-2Pa (Ps-2Pa; GIFPIFAKLLGKVIKVASSLISKGRTE) are amphibian peptides with broad spectrum antimicrobial activities and cytotoxicity against mammalian cells. In the membrane-mimetic solvent 50% (v/v) trifluoroethanol–H2O, both peptides adopt a well-defined α-helical conformation that extends over almost all the sequence and incorporates a flexible bend. Both peptides significantly (p < 0.05) stimulate the rate of release of insulin from BRIN-BD11 clonal β-cells at concentrations ≥ 0.1 nM but produce loss of integrity of the plasma membrane at concentrations ≥ 1 μM. Increasing cationicity by the substitution Glu17 → l-Lys in Ps-1Pb and Glu27 → l-Lys in Ps-2Pa generates analogues with increased cytotoxicity and reduced insulin-releasing potency. In contrast, the analogues [R8r]Ps-1Pb and [K8k,K19k]Ps-2Pa, incorporating d-amino acid residues to destabilize the α-helical domains, retain potent insulin-releasing activity but are nontoxic to BRIN-BD11 cells at concentrations of 3 μM. [R8r]Ps-1Pb produces a significant increase in insulin release rate at 0.3 nM and [K8k,K19k]Ps-2Pa at 0.01 nM. Both analogues show low hemolytic activity (IC50 > 100 μM) but retain broad-spectrum antimicrobial activity and remain cytotoxic to a range of human tumor cell lines, albeit with lower potency than the naturally occurring peptides. These analogues show potential for development into agents for type 2 diabetes therapy.

Baicalin Alleviates Silica-Induced Lung Inflammation and Fibrosis by Inhibiting the Th17 Response in C57BL/6 Mice
Tao Liu - ,
Wujing Dai - ,
Chao Li - ,
Fangwei Liu - ,
Ying Chen - ,
Dong Weng - , and
Jie Chen *
Silicosis is an inflammatory and fibrotic lung disease caused by inhalation of silica. Th17 cells play a key role in causing silica-induced lung inflammation and fibrosis. Baicalin, a compound isolated from the Chinese herb Huangqin, could suppress the differentiation of Th17 cells and alleviate inflammation. However, there are very few reports of the immunoregulatory mechanisms of baicalin in experimental silica-induced lung inflammation and fibrosis. In our study, mice were exposed to silica by intratracheal instillation, and in this way we established an experimental silicosis model. To elucidate the effects and mechanisms of baicalin in silica-induced inflammation and fibrosis, we used baicalin to treat the developed mouse model of silicosis. Treatment with baicalin attenuated the accumulation of inflammatory cells and led to milder pathological inflammatory and fibrotic changes in lung tissues. Baicalin affected the immunological balance between Th17 and Treg responses. Therefore, baicalin caused a decrease in Th17 cells by stimulating Treg cells and by inhibiting IL-6 and IL-23. We further demonstrated that silica-induced Th1 and Th2 immune responses were both inhibited by increased Treg activation, which was promoted by baicalin. Our findings confirmed the potential functions of baicalin in inhibiting the Th17 response and reducing silica-induced inflammation and fibrosis.

Phomanolides A and B from the Fungus Phoma sp.: Meroterpenoids Derived from a Putative Tropolonic Sesquiterpene via Hetero-Diels–Alder Reactions
Jinyu Zhang - ,
Ling Liu - ,
Bo Wang - ,
Yang Zhang - ,
Lili Wang - ,
Xingzhong Liu - , and
Yongsheng Che *
Phomanolides A (1) and B (2), unique meroterpenoids with new pentacyclic and tetracyclic skeletons, respectively, and phomanoxide (3), the double-epoxidation product of a putative biosynthetic precursor of 1 and 2, were isolated from the solid substrate fermentation cultures of the fungus Phoma sp., along with the known compound eupenifeldin (4). The structures of 1–3 were elucidated based on NMR spectroscopic data and electronic circular dichroism calculations and further secured by X-ray crystallography. Biogenetically, compounds 1 and 2 could be derived from a hypothetical monotropolonic sesquiterpene intermediate via hetero-Diels–Alder reactions. Compound 4 showed potent antiproliferative effects against three human glioma cell lines, with IC50 values of 0.08–0.13 μM.
Notes

Avertoxins A–D, Prenyl Asteltoxin Derivatives from Aspergillus versicolor Y10, an Endophytic Fungus of Huperzia serrata
Mingzi Wang - ,
Mingwei Sun - ,
Huilin Hao - , and
Chunhua Lu *
Aspergillus versicolor Y10 is an endophytic fungus isolated from Huperzia serrata, which showed inhibitory activity against acetylcholinesterase. An investigation of the chemical constituents of Y10 led to the isolation of four new prenylated asteltoxin derivatives, named avertoxins A–D (2–5), together with the known mycotoxin asteltoxin (1). In the present study, we report structure elucidation for 2–5 and the revised NMR assignments for asteltoxin and demonstrated that avertoxin B (3) is an active inhibitor against human acetylcholinesterase with the IC50 value of 14.9 μM (huperzine A as the positive control had an IC50 of 0.6 μM). In addition, the cytotoxicity of asteltoxin (1) and avertoxins A–D (2–5) against MDA-MB-231, HCT116, and HeLa cell lines was evaluated.

Absolute Configurations of Zingiberenols Isolated from Ginger (Zingiber officinale) Rhizomes
Ashot Khrimian *- ,
Shyam Shirali - , and
Filadelfo Guzman
Two stereoisomeric zingiberenols in ginger were identified as (3R,6R,7S)-1,10-bisaboladien-3-ol (2) and (3S,6R,7S)-1,10-bisaboladien-3-ol (5). Absolute configurations were assigned by utilizing 1,10-bisaboladien-3-ol stereoisomers and two gas-chromatography columns: a 25 m Hydrodex-β-6TBDM and 60 m DB-5MS. The C-6 and C-7 absolute configurations in both zingiberenols match those of zingiberene present abundantly in ginger rhizomes. Interestingly, zingiberenol 2 has recently been identified as a male-produced sex pheromone of the rice stink bug, Oebalus poecilus, thus indicating that ginger plants may be a potential source of the sex pheromone of this bug.

1,9-seco-Bicyclic Polyprenylated Acylphloroglucinols from Hypericum uralum
Jing-Jing Zhang - ,
Xing-Wei Yang - ,
Xia Liu - ,
Jun-Zeng Ma - ,
Yang Liao - , and
Gang Xu *
Hyperuralones C–H (1–6), six new 1,9-seco-bicyclic polyprenylated acylphloroglucinols (1,9-seco-BPAPs) derived from the normal polyprenylated acylphloroglucinols with a bicyclo[3.3.1]nonane-2,4,9-trione core, together with six known analogues, were isolated from the aerial parts of Hypericum uralum. The structures of 1–6 were elucidated on the basis of the interpretation of NMR and MS spectroscopic data. The structure of attenuatumione B, a known compound isolated from H. attenuatum, was revised to that of a 1,9-seco-BPAP by NMR spectroscopic analysis and previous biomimetic synthesis methods. The inhibitory activities of these isolates on acetylcholinesterase were tested, and compounds 1 and 2 exhibited moderate activities with IC50 values of 9.6 and 7.1 μM, respectively.

Synthesis of Alocasin A
Se Hun Kim - and
Jonathan Sperry *
Herein is reported a synthesis of alocasin A (1), an alkaloid component of Alocasia macrorrhiza, a herbaceous plant used in folk medicine throughout southern Asia. A double Suzuki–Miyaura cross-coupling reaction between a 3-borylindole and 2,5-dibromopyrazine was used to assemble the heteroaromatic framework of the natural product. Removal of the protecting groups gave a synthetic sample of 1, the spectroscopic data of which matched those in the isolation report of this compound.
Book Reviews
Review of Biology and Chemistry of Jerusalem Artichoke, Helianthus tuberosus L.
John H. Cardellina II,
Additions and Corrections
Correction to Advanced Structural Determination of Diterpene Esters Using Molecular Modeling and NMR Spectroscopy
Louis-Félix Nothias-Scaglia - ,
Jean-François Gallard - ,
Vincent Dumontet - ,
Fanny Roussi - ,
Jean Costa - ,
Bogdan I. Iorga - ,
Julien Paolini - , and
Marc Litaudon
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