Acetylenic spiroketal enol ethers from Artemisia rupestris and their synergistic antibacterial effects on methicillin-resistant Staphylococcus aureus.

Synergistic bioassay-guided isolation of the extracts of Artemisia rupestris L, which belongs to the family Asteraceae, afforded two acetylenic spiroketal enol ethers, namely rupesdiynes A (1) and B (2). Their structures were determined based on spectroscopic analysis and experimental and calculated ECD investigations. The two compounds exhibited synergistic activity and were able to reduce the minimum inhibitory concentration (MIC) of oxacillin four-fold, with a fractional inhibitory concentration index (FICI) of 0.5 in combination with oxacillin against the oxacillin-resistant EMRSA-16. Biofilm formation inhibitory and Ethidium bromide (EtBr) efflux assay were further employed to verify the possible mechanism of the synergistic antibacterial effect. Additionally, molecular docking studies were conducted to investigate the binding affinities of the two compounds with penicillin-binding protein 2a (PBP2a) of EMRSA-16. Taken together, rupesdiynes A (1) and rupesdiyne B (2) showed moderate synergistic activity against EMRSA-16 with oxacillin via inhibiting biofilm formation and efflux pump activity, respectively.

Comparative Photoaffinity Profiling of Omega-3 Signaling Lipid Probes Reveals Prostaglandin Reductase 1 as a Metabolic Hub in Human Macrophages.

The fish oil constituent docosahexaenoic acid (DHA, 22:6 n-3) is a signaling lipid with anti-inflammatory properties. The molecular mechanisms underlying the biological effect of DHA are poorly understood. Here, we report the design, synthesis, and application of a complementary pair of bio-orthogonal, photoreactive probes based on the polyunsaturated scaffold DHA and its oxidative metabolite 17-hydroxydocosahexaenoic acid (17-HDHA). In these probes, an alkyne serves as a handle to introduce a fluorescent reporter group or a biotin-affinity tag via copper(I)-catalyzed azide-alkyne cycloaddition. This pair of chemical probes was used to map specific targets of the omega-3 signaling lipids in primary human macrophages. Prostaglandin reductase 1 (PTGR1) was identified as an interaction partner that metabolizes 17-oxo-DHA, an oxidative metabolite of 17-HDHA. 17-oxo-DHA reduced the formation of pro-inflammatory lipids 5-HETE and LTB4 in human macrophages and neutrophils. Our results demonstrate the potential of comparative photoaffinity protein profiling for the discovery of metabolic enzymes of bioactive lipids and highlight the power of chemical proteomics to uncover new biological insights.

Physiologically Relevant Concentrations of Dolutegravir, Emtricitabine, and Efavirenz Induce Distinct Metabolic Alterations in HeLa Epithelial and BV2 Microglial Cells.

Microglia, the resident brain phagocytes, likely play a key role in human immunodeficiency virus (HIV) infection of the central nervous system (CNS) and subsequent neuropathogenesis; however, the nature of the infection-induced changes that yield damaging CNS effects and the stimuli that provoke microglial activation remains elusive, especially in the current era of using antiretroviral (ARV) drugs for ARV therapy (ART). Altered microglial metabolism can modulate cellular functionality and pathogenicity in neurological disease. While HIV infection itself alters brain energy metabolism, the effect of ARV drugs, particularly those currently used in treatment, on metabolism is understudied. Dolutegravir (DTG) and emtricitabine (FTC) combination, together with tenofovir (TAF or TDF), is one of the recommended first line treatments for HIV. Despite the relatively good tolerability and safety profile of FTC, a nucleoside reverse transcriptase inhibitor, and DTG, an integrase inhibitor, adverse side effects have been reported and highlight a need to understand off-target effects of these medications. We hypothesized that similar to previous ART regimen drugs, DTG and FTC side effects involve mitochondrial dysfunction. To increase detection of ARV-induced mitochondrial effects, highly glycolytic HeLa epithelial cells were forced to rely on oxidative phosphorylation by substituting galactose for glucose in the growth media. We assessed ATP levels, resazurin oxidation-reduction (REDOX), and mitochondrial membrane potential following 24-hour exposure (to approximate effects of one dose equivalent) to DTG, FTC, and efavirenz (EFV, a known mitotoxic ARV drug). Further, since microglia support productive HIV infection, act as latent HIV cellular reservoirs, and when dysfunctional likely contribute to HIV-associated neurocognitive disorders, the experiments were repeated using BV2 microglial cells. In HeLa cells, FTC decreased mitochondrial REDOX activity, while DTG, similar to EFV, impaired both mitochondrial ATP generation and REDOX activity. In contrast to HeLa cells, DTG increased cellular ATP generation and mitochondrial REDOX activity in BV2 cells. Bioenergetic analysis revealed that DTG, FTC, and EFV elevated BV2 cell mitochondrial respiration. DTG and FTC exposure induced distinct mitochondrial functional changes in HeLa and BV2 cells. These findings suggest cell type-specific metabolic changes may contribute to the toxic side effects of these ARV drugs.

Myeloid Cell-Targeted Nanocarriers Efficiently Inhibit Cellular Inhibitor of Apoptosis for Cancer Immunotherapy.

Immune-checkpoint blockers can promote sustained clinical responses in a subset of cancer patients. Recent research has shown that a subpopulation of tumor-infiltrating dendritic cells functions as gatekeepers, sensitizing tumors to anti-PD-1 treatment via production of interleukin-12 (IL-12). Hypothesizing that myeloid cell-targeted nanomaterials could be used to deliver small-molecule IL-12 inducers, we performed high-content image-based screening to identify the most efficacious small-molecule compounds. Using one lead candidate, LCL161, we created a myeloid-targeted nanoformulation that induced IL-12 production in intratumoral myeloid cells in vivo, slowed tumor growth as a monotherapy, and had no significant systemic toxicity. These results pave the way for developing combination immunotherapeutics by harnessing IL-12 production for immunostimulation.

The In Vitro Immunomodulatory Effects Of Gold Nanoparticles Synthesized From Hypoxis hemerocallidea Aqueous Extract And Hypoxoside On Macrophage And Natural Killer Cells.

BACKGROUND: Macrophages and Natural Killer (NK) cells are an integral part of the innate immune system. These cells produce pro-inflammatory cytokines in response to bacterial infections. However, prolonged inflammation can be a contributing factor in the etiology of several diseases such as rheumatoid arthritis, inflammatory bowel disease, multiple sclerosis, psoriasis and eczema. Reducing the secretion of pro-inflammatory cytokines is an effective treatment strategy for these conditions. Gold nanoparticles (AuNPs) have been shown to have immunosuppressive effects. Extracts of the Hypoxis hemerocallidea plant have also been shown to have immunomodulatory effects. It has been demonstrated previously that extracts of the H. hemerocallidea can be used to synthesize AuNPs. PURPOSE: This study aimed to investigate whether AuNPs synthesized using H. hemerocallidea extract and its major secondary metabolite, hypoxoside, have any immunomodulatory effects in macrophages and NK cells. METHODOLOGY: AuNPs derived from the H. hemerocallidea extract were synthesized as previously described. Using similar methodologies, this study shows for the first time the synthesis of AuNPs from hypoxoside. The AuNPs were characterized using several optical and spectroscopic techniques. The immunomodulatory effects of the aqueous extract of H. hemerocallidea, hypoxoside, as well as the AuNPs produced from the extract and hypoxoside, were investigated by measuring the cytokine levels in macrophages (IL-1ß, IL-6 and TNF-α) and NK cells (IFN-γ) using solid phase sandwich ELISA technique. RESULTS: The results show that spherical AuNPs (average size 26 ± 2 nm) were synthesized from hypoxoside. The results also show that the four treatments (H. hemerocallidea extract, hypoxoside and their respective AuNPs can lower the pro-inflammatory cytokine levels in the macrophages cells, while only AuNPs produced from hypoxoside can reduce cytokine responses in NK cells. CONCLUSION: This study shows that all four treatments investigated here could be further explored for the development of anti-inflammatory therapies.

Upregulation of cystathionine-γ-lyase/hydrogen sulfide pathway underlies the celecoxib counteraction of cyclosporine-induced hypertension and renal insult in rats.

We recently reported that celecoxib, a selective cyclooxygenase-2 (COX2) inhibitor, counteracts the adverse circulatory and renal actions of cyclosporine (CSA). Despite the seemingly advantageous nature of this interaction particularly in clinical settings that necessitate the combined use of the two drugs such as immune-related arthritis, the underlying mechanism remains elusive. This prompted us to test the hypothesis that the facilitation of the cystathionine-γ-lyase (CSE)/hydrogen sulfide (H2S) signaling accounts for such favorable effects of celecoxib on CSA nephrotoxicity. The data showed that the 10-day co-treatment of rats with celecoxib (10 mg/kg/day) ameliorated the hypertensive and biochemical and renal structural damages caused by CSA (20 mg/kg/day). Celecoxib also reversed the CSA-evoked (i) reductions in the tubular and glomerular protein expression of CSE and levels of H2S, prostaglandin E2 (PGE2), and total antioxidant capacity (TAC), and (ii) increases in inflammatory (tumor necrosis factor-α, TNF-α), fibrotic (transforming growth factor-ß1, TGF-ß1) and apoptotic (caspase-3) cytokines. These celecoxib effects disappeared when rats were treated concomitantly with the CSE inhibitor DL-propargylglycine (DL-PAG), indicating the importance of the CSE-derived H2S in mediating the renoprotective action of celecoxib. This view is bolstered by the observation that the beneficial hemodynamic and renal actions of celecoxib were replicated after supplementation of rats with sodium sulfide (Na2S, H2S donor). Together, the increased abundance of renal CSE and H2S and subsequent dampening down of inflammatory, fibrotic, oxidant, and apoptotic pathways play pivotal roles in the capacity of celecoxib to compromise the troublesome hypertensive and nephrotoxic insults caused by CSA in rats.

Anti-hepatitis B virus effects of the traditional Chinese herb Artemisia capillaris and its active enynes.

ETHNOPHARMACOLOGICAL RELEVANCE: Artemisia capillaris (Yin-Chen) is a famous traditional Chinese medicine (TCM) for treating acute and chronic hepatitis in China. Enynes are one type of characteristic constituents in this herb, while their anti-hepatitis B virus (anti-HBV) properties have not been systemically investigated. AIM OF THE STUDY: This study is to reveal the active part of A. capillaris, and systemically investigate the enynes and their anti-HBV activity. MATERIALS AND METHODS: The total extract and each fraction of A. capillaris were assayed for the anti-HBV activity to reveal the active part. Bioassay-guided fractionation using various chromatographic techniques yielded the enynes, whose structures were elucidated by spectroscopic analyses and ECD calculations. The anti-HBV properties inhibiting HBsAg and HBeAg secretions and HBV DNA replication were evaluated on HepG 2.2.15 cell line in vitro. RESULTS: ACT-2 and ACT-3 was revealed to be the respective active and toxic part of A. capillaris. Twelve enynes (1-12) involving four new ones (1-4) and two unusual enyne analogs (13-14) were isolated from the active part (ACT-2). All the isolates were assayed for their anti-HBV activity, and the preliminary structure-activity relationships were summarized based on the structural features. In particular, compound 4 could significantly inhibit the secretions of HBsAg and HBeAg, and HBV DNA replication with IC50 values of 197.2 (SI > 5.1), 48.7 (SI > 20.5) and 9.8 (SI > 102) µM. CONCLUSIONS: Enynes are responsible for the anti-HBV effects of A. capillaris. Hydroxyl and glycosyl groups are preferable for maintaining activity. This is the first time to systematically investigate the anti-HBV activity of enynes in A. capillaris, which provides valuable information for understanding the ethnopharmacological application of Yin-Chen.

A new sesquiterpene from Kalimeris integrifolia.

A new sesquiterpene kalinturoside A (1), and 17 known compounds friedelan-3-ol (2), 24-ethyl-5a-cholesta-7, 22(E)-dien-3-one (3), friedelin (4), syringaresinol (5), α-spinasterol (6), ciwujiatone (7), syringic acid (8), scopoletin (9), apocynin (10), 1-(3-hydroxy-4, 5-dimethoxyphenyl)ethan-1-one (11), apigenin (12), 5-hydroxymethylfurfural (13), stigmasterol-3-O-ß-d-glucopy-ranoside (14), bidenoside C (15), citrusin (16), irioresinol A (17) and syringaresinol-4-O-ß-d-glucopyranoside (18) were isolated from the herbs of Kalimeris integrifolia. The structures of these compounds were elucidated using spectroscopic techniques such as NMR and MS. All of the compounds were isolated from this genus for the first time.

Carlina acaulis Exhibits Antioxidant Activity and Counteracts Aß Toxicity in Caenorhabditis elegans.

Carlina acaulis is a medicinal plant that has shown antioxidant activity in in vitro studies, but to date no corresponding in vivo data is available. Therefore, in the present study the antioxidant activity and its impact in counteracting Aß toxicity were studied in the Caenorhabditis elegans model. A dichloromethane extract of the roots of C. acaulis was prepared and characterised via gas-liquid-chromatography/mass-spectrometry (GLC-MS). The in vitro antioxidant activity was confirmed via 2,2-diphenyl-1-picrylhydracyl assay. The extract was further separated by thin layer chromatography into two fractions, one of which was a fraction of the dichloromethane extract of C. acaulis containing mostly Carlina oxide (CarOx). Different strains of C. elegans were employed to study the expression of hsp-16.2p::GFP as a marker for oxidative stress, delocalisation of the transcription factor DAF-16 as a possible mechanism of antioxidant activity, the effect of the drug under lethal oxidative stress, and the effect against beta-amyloid (Aß) toxicity in a paralysis assay. The C. acaulis extract and CarOx showed high antioxidant activity (stress reduction by 47% and 64%, respectively) in C. elegans and could activate the transcription factor DAF-16 which directs the expression of anti-stress genes. In paralysis assay, only the total extract was significantly active, delaying paralysis by 1.6 h. In conclusion, in vivo antioxidant activity was shown for C. acaulis for the first time in the C. elegans model. The active antioxidant compound is Carlina oxide. This activity, however, is not sufficient to counteract Aß toxicity. Other mechanisms and possibly other active compounds are involved in this effect.

Promising anti-diabetic potential of capillin and capillinol isolated from Artemisia capillaris.

Caffeoylquinic acids, flavonoids, and coumarins isolated from Artemisia capillaris have recently emerged as therapeutic candidates for diabetes and diabetic complications; however, there have been very few studies of the anti-diabetic potential of polyacetylenes. In the present study, we investigated the anti-diabetic potential of two polyacetylenes isolated from A. capillaris, namely capillin and capillinol by investigating their ability to inhibit α-glucosidase, protein tyrosine phosphatase 1B (PTP1B), and rat lens aldose reductase (RLAR). Capillin displayed potent inhibitory activity against α-glucosidase, PTP1B, and RLAR, while capillinol showed moderate inhibitory activity against α-glucosidase and PTP1B at the concentrations tested. In addition, a kinetic study revealed that capillin inhibited α-glucosidase and RLAR in a noncompetitive manner, while inhibited PTP1B in a mixed-type manner. Capillinol inhibited α-glucosidase and PTP1B in a mixed-type manner. Docking simulations of these compounds demonstrated negative binding energies and close proximity to residues in the binding pocket of PTP1B, indicating that these polyacetylenes have a high affinity and tight binding capacity for the active site of the enzyme. Furthermore, capillin dose-dependently inhibited peroxynitrite (ONOO(-))-mediated tyrosine nitration. The results clearly demonstrate the promising potential of capillin and capillinol as therapeutic interventions for the management of diabetes as well as diabetes-associated complications.

Role of Nitric Oxide and Hydrogen Sulfide in the Vasodilator Effect of Ursolic Acid and Uvaol from Black Cherry Prunus serotina Fruits.

The present research aimed to isolate the non-polar secondary metabolites that produce the vasodilator effects induced by the dichloromethane extract of Prunus serotina (P. serotina) fruits and to determine whether the NO/cGMP and the H2S/KATP channel pathways are involved in their mechanism of action. A bioactivity-directed fractionation of the dichloromethane extract of P. serotina fruits led to the isolation of ursolic acid and uvaol as the main non-polar vasodilator compounds. These compounds showed significant relaxant effect on rat aortic rings in an endothelium- and concentration-dependent manner, which was inhibited by NG-nitro-L-arginine methyl ester (L-NAME), DL-propargylglycine (PAG) and glibenclamide (Gli). Additionally, both triterpenes increased NO and H2S production in aortic tissue. Molecular docking studies showed that ursolic acid and uvaol are able to bind to endothelial NOS and CSE with high affinity for residues that form the oligomeric interface of both enzymes. These results suggest that the vasodilator effect produced by ursolic acid and uvaol contained in P. serotina fruits, involves activation of the NO/cGMP and H2S/KATP channel pathways, possibly through direct activation of NOS and CSE.

A spiroketal-enol ether derivative from Tanacetum vulgare selectively inhibits HSV-1 and HSV-2 glycoprotein accumulation in Vero cells.

The inhibitory effects of Tanacetum vulgare rhizome extracts on HSV-1 and HSV-2 in vitro replication were assessed. Unlike extracts obtained from the aerial parts, adsorption inhibition and virucidal activities seemed not to be relevant for the observed antiviral action of tansy rhizome extracts. Instead, the most significant effects were the inhibition of virus penetration and a novel mechanism consisting of the specific arrest of viral gene expression and consequently the decrease of viral protein accumulation within infected cells. Through a bioactivity-guided fractionation protocol we isolated and identified the spiroketal-enol ether derivative (E)-2-(2,4-hexadiynyliden)-1,6-dioxaspiro[4.5]dec-3-ene as the active compound responsible for this inhibitory effect.

The medicinal chemistry of genus Aralia.

The genus Aralia contains many plants used medicinally in Asia and the Americas. Although many members of this genus are used medicinally, the vast majority of this genus has not been explored chemically. The species of Aralia that have been explored chemically have yielded compounds of several classes, including triterpenoid saponins, sterols, diterpenoids, and acetylenic lipids. Many of the biologically active components found in genus Aralia have been evaluated for their potential as lead compounds for drug discovery. This review will explore the medicinal chemistry of compounds reported from genus Aralia, and future prospects for this genus will be considered.

The efficacy of passion fruit juice as an endodontic irrigant compared with sodium hypochlorite solution: an in vitro study.

AIM: To assess the effectiveness of several concentrations of two forms of passion fruit juice (PFJ) in the elimination of Enterococcus faecalis and to compare the antibacterial property of PFJ with sodium hypochlorite (NaOCl) as an intracanal irrigant. METHODS: Two types of PFJs, aqueous and alcohol extracts, were prepared and a minimum inhibitory concentration (MIC) test was performed with both the extracts against E. faecalis. Two concentrations of each extract were selected from the results given by the MIC test and subjected to a broth dilution test (BDT) for nine different time periods. After each time period, samples were inoculated in brain-heart infusion agar plates for 24 h at 37°C and results were compared statistically. RESULTS: The MIC test showed that E. faecalis was sensitive to PFJ extracts at various concentrations. The results of the BDT showed a negative growth of E. faecalis by PFJ alcohol 20% at 30 min, PFJ aqueous 20% at 1 h, NaOCl 2.5% at 10 min and NaOCl 5.25% at 1 min. NaOCl showed a much better antibacterial efficacy than PFJ. CONCLUSIONS: The PFJ alcoholic and aqueous extracts had an antibacterial effect against E. faecalis. As PFJ shows promising results, further research in this field could lead to much better results as compared to NaOCl.

Identification of 6-octadecynoic acid from a methanol extract of Marrubium vulgare L. as a peroxisome proliferator-activated receptor γ agonist.

6-Octadecynoic acid (6-ODA), a fatty acid with a triple bond, was identified in the methanol extract of Marrubium vulgare L. as an agonist of peroxisome proliferator-activated receptor γ (PPARγ). Fibrogenesis caused by hepatic stellate cells is inhibited by PPARγ whose ligands are clinically used for the treatment of diabetes. Plant extracts of Marrubium vulgare L., were screened for activity to inhibit fibrosis in the hepatic stellate cell line HSC-T6 using Oil Red-O staining, which detects lipids that typically accumulate in quiescent hepatic stellate cells. A methanol extract with activity to stimulate accumulation of lipids was obtained. This extract was found to have PPARγ agonist activity using a luciferase reporter assay. After purification using several chromatographic methods, 6-ODA, a fatty acid with a triple bond, was identified as a candidate of PPARγ agonist. Synthesized 6-ODA and its derivative 9-octadecynoic acid (9-ODA), which both have a triple bond but in different positions, activated PPARγ in a luciferase reporter assay and increased lipid accumulation in 3T3-L1 adipocytes in a PPARγ-dependent manner. There is little information about the biological activity of fatty acids with a triple bond, and to our knowledge, this is the first report that 6-ODA and 9-ODA function as PPARγ agonists.

Bioactive acetylenic metabolites.

This article focuses on anticancer, and other biological activities of acetylenic metabolites obtained from plants and fungi. Acetylenic compounds belong to a class of molecules containing triple bond(s). Naturally occurring acetylenics are of particular interest since many of them display important biological activities and possess antitumor, antibacterial, antimicrobial, antifungal, and immunosuppressive properties. There are of great interest for medicine, pharmacology, medicinal chemistry, and pharmaceutical industries. This review presents structures and describes cytotoxic activities of more than 100 acetylenic metabolites, including fatty alcohols, ketones, and acids, acetylenic cyclohexanoids, spiroketal enol ethers, and carotenoids isolated from fungi and plants.

Co-administration of a commonly used Zimbabwean herbal treatment (African potato) does not alter the pharmacokinetics of lopinavir/ritonavir.

OBJECTIVE: African potato (Hypoxis obtusa) is commonly used in Sub-Saharan Africa as a complementary herbal remedy for HIV-infected patients. It is unknown whether or not co-administration of African potato alters the pharmacokinetics of protease inhibitor antiretrovirals. The objective of this study was to investigate the impact of the African potato on the steady-state pharmacokinetics of ritonavir-boosted lopinavir (LPV/r). METHODS: Sixteen adult volunteers were administered LPV/r 400/100 mg twice a day for 14 days, followed by concomitant administration with African potato given once daily for 7 days. Lopinavir plasma exposure as estimated by the area under the concentration-time curve over the 12-h dosing interval (AUC(0-12h), AUCτ) was determined on day 14 and again on day 21. Lopinavir in plasma was analyzed using a validated liquid chromatography with tandem mass spectrometry (LC-MS/MS) method. Steady-state AUCτ and the maximum concentration following dose administration (C(max)) were determined using non-compartmental methods using WinNonlin Professional version 5.2.1. Statistical analyses were performed using Stata version 12.1. RESULTS: Co-administration of African potato was not associated with any change in lopinavir AUCτ, C(max), or C(trough). CONCLUSIONS: African potato when taken concomitantly with LPV/r is well-tolerated and not associated with clinically significant changes in lopinavir pharmacokinetics.

17ß-estradiol induces vasorelaxation by stimulating endothelial hydrogen sulfide release.

Estrogen exerts vascular protective effects, but the underlying mechanisms remain to be understood fully. In recent years, hydrogen sulfide (H(2)S) has increasingly been recognized as an important signaling molecule in the cardiovascular system. Vascular H(2)S is produced from L-cysteine, catalyzed by cystathionine γ-lyase (CSE). In our study, apolipoprotein E (ApoE)-deficient mice were ovariectomized and implanted with placebo (OVX mice) or 17ß-estradiol (E(2)) pellets (OVX + E(2) mice). Compared with OVX mice, OVX + E(2) mice showed increased plasma H(2)S levels (P = 0.012) and decreased aortic lesion area (P = 0.028). These effects were largely reversed when supplementing with the irreversible CSE inhibitor DL-propargylglycine (PPG) in the OVX + E(2) + PPG mice. Meanwhile, the nitric oxide and prostacyclin-resistant responses to cumulative application of acetylcholine (ACh) were studied among all the three groups of femoral arteries. Compared with the arteries in the OVX group, the vasodilator sensitivity of arteries to ACh was increased in the OVX + E(2) group and attenuated in the OVX + E(2) + PPG group. E(2) and estrogen receptor (ER) α agonist 4',4″,4'″-(4-propyl-[1H]-pyrazole-1,3,5-triyl) trisphenol rapidly increased H(2)S release in human endothelial cells, but not partially selective ERß agonist 2,3-bis-(4-hydroxyphenyl)-propionitrile. These effects were inhibited by ER antagonist ICI 182780 or by protein kinase G (PKG) inhibitor KT5823. Furthermore, endothelial PKG activity was increased by E(2) (P = 0.003) and E(2)-induced vasodilation was inhibited by KT5823 (P = 0.009). In conclusion, the endothelial CSE/H(2)S pathway is activated by E(2) through PKG, which leads to vasodilation. These actions may be relevant to estrogen's anti-atherogenic effect.

Chemical constituents of Anacolosa pervilleana and their antiviral activities.

In an effort to identify novel inhibitors of Chikungunya (CHIKV) and Dengue (DENV) virus replication, a systematic study with 820 ethyl acetate extracts of Madagascan plants was performed in a virus-cell-based assay for CHIKV and a DENV NS5 RNA-dependant RNA polymerase (RdRp) assay. The extract obtained from the leaves of Anacolosa pervilleana was selected for its significant activity in both assays. One new (E)-tridec-2-en-4-ynedioic acid named anacolosine (1), together with three known acetylenic acids, the octadeca-9,11,13-triynoic acid (2), (13E)-octadec-13-en-9,11-diynoic acid (3), (13E)-octadec-13-en-11-ynoic acid (4), two terpenoids, lupenone (5) and ß-amyrone (6), and one cyanogenic glycoside, (S)-sambunigrin (7) were isolated. Their structures were elucidated by comprehensive analyses of NMR spectroscopy and mass spectrometry data. The inhibitory potency of these compounds was evaluated on CHIKV, DENV RdRp and West-Nile polymerase virus (WNV RdRp). Both terpenoids showed a moderate activity against CHIKV (EC(50) 77 and 86 µM, respectively) and the acetylenic acids produced IC(50) values around 3 µM in the DENV RdRp assay.

Bioassay-directed isolation and identification of phytotoxic and fungitoxic acetylenes from Conyza canadensis.

Conyza canadensis (L.) Cronquist syn. (horseweed) is a problematic and invasive weed with reported allelopathic properties. To identify the phytotoxic constituents of the aerial parts, a systematic bioactivity-guided fractionation of the dichloromethane extract was performed. Three active enyne derivatives, (2Z,8Z)-matricaria acid methyl ester, (4Z,8Z)-matricaria lactone, and (4Z)-lachnophyllum lactone, were identified. The lactones inhibited growth of the monocot Agrostis stolonifera (bentgrass) and the dicot Lactuca sativa (lettuce) at 1 mg mL(-1), while the (2Z,8Z)-matricaria acid methyl ester was less active. In a dose-response screening of the lactones for growth inhibitory activity against Lemna paucicostata , (4Z)-lachnophyllum lactone was the most active with an IC50 of 104 µM, while the (4Z,8Z)-matricaria lactone was less active (IC50 of 220 µM). In a fungal direct bioautography assay, the two lactones at 10 and 100 µg/spot inhibited growth of the plant pathogenic fungi Colletotrichum acutatum , Colletotrichum fragariae , and Colletotrichum gloeosporioides . In a dose-response screening of the lactones against six different plant pathogenic fungi, (4Z,8Z)-matricaria lactone was more active than the commercial fungicide azoxystrobin on Col. acutatum , Col. fragariae , and Col. gloeosporioides at 30 µM and about as active as the commercial fungicide captan against Col. gloeosporioides , while (4Z)-lachnophyllum lactone was less active.