Tolypocaibols: Antibacterial Lipopeptaibols from a Tolypocladium sp. Endophyte of the Marine Macroalga Spongomorpha arcta

Two new lipopeptaibols, tolypocaibols A (1) and B (2), and the mixed NRPS-polyketide-shikimate natural product maximiscin [(P/M)-3)] were isolated from a Tolypocladium sp. fungal endophyte of the marine alga Spongomorpha arcta. Analysis of NMR and mass spectrometry data revealed the amino acid sequences of the lipopeptaibols, which both comprise 11 residues with a valinol C-terminus and a decanoyl acyl chain at the N-terminus. The configuration of the amino acids was determined by Marfey's analysis. Tolypocaibols A (1) and B (2) showed moderate, selective inhibition against Gram-positive and acid-fast bacterial strains, while maximiscin [(P/M)-3)] showed moderate, broad-spectrum antibiotic activity.

Caryophyllene Sesquiterpenes from a Chaetomium globosum Endophyte of the Canadian Medicinal Plant Empetrum nigrum

Punctaporonins T (1) and U (2), new caryophyllene sesquiterpenes, were isolated with three known punctaporonins, A (3), B (4), and C (5), from the endophytic fungus Chaetomium globosum (TC2-041). The structures and relative configurations of punctaporonins T and U were elucidated based on a combination of HRESIMS, 1D/2D NMR spectroscopic analysis, and X-ray diffraction analysis, while their absolute configuration is presumed to be consistent with the co-isolated 3-5 on biogenetic arguments. Compound 1 showed weak inhibitory activity against both Mycobacterium tuberculosis and Staphylococcus aureus.

Annotation of natural product compound families using molecular networking topology and structural similarity fingerprinting

Spectral matching of MS² fragmentation spectra has become a popular method for characterizing natural products libraries but identification remains challenging due to differences in MS² fragmentation properties between instruments and the low coverage of current spectral reference libraries. To address this bottleneck we present Structural similarity Network Annotation Platform for Mass Spectrometry (SNAP-MS) which matches chemical similarity grouping in the Natural Products Atlas to grouping of mass spectrometry features from molecular networking. This approach assigns compound families to molecular networking subnetworks without the need for experimental or calculated reference spectra. We demonstrate SNAP-MS can accurately annotate subnetworks built from both reference spectra and an in-house microbial extract library, and correctly predict compound families from published molecular networks acquired on a range of MS instrumentation. Compound family annotations for the microbial extract library are validated by co-injection of standards or isolation and spectroscopic analysis. SNAP-MS is freely available at www.npatlas.org/discover/snapms .

Glacier recession alters stream water quality characteristics facilitating bloom formation in the benthic diatom Didymosphenia geminata

Glaciers provide cold, turbid runoff to many mountain streams in the late summer and buffer against years with low snowfall. The input of glacial meltwater to streams maintains unique habitats and support a diversity of stream flora and fauna. In western Canada, glaciers are anticipated to retreat by 60-80% by the end of the century, and this retreat will invoke widespread changes in mountain ecosystems. We used a space-for-time substitution along a gradient of glacierization in western Canada to develop insights into changes that may occur in glaciated regions over the coming decades. Here we report on observed changes in physical (temperature, turbidity), and chemical (dissolved and total nutrients) characteristics of mountain streams and the associated shifts in their diatom communities during de-glacierization. Shifts in habitat characteristics across gradients include changes in nutrient concentrations, light penetration, temperatures, and flow, all of which have led to distinct changes in diatom community composition. Importantly, glacial-fed rivers were 3-5 °C cooler than rivers without glacial contributions. Declines in glacial meltwater contribution to streams resulted in shifts in the timing of nutrient fluxes and lower concentrations of total phosphorus (TP), soluble reactive phosphorus (SRP), and higher dissolved inorganic nitrogen (DIN) and light penetration. The above set of conditions were linked to the overgrowth of the benthic diatom Didymosphenia geminata. These changes in stream condition and D. geminata colony development primarily occurred in streams with marginal (2-5%) to no glacier cover. Our data support a hypothesis that climate-induced changes in river hydrochemistry and physical condition lead to a phenological mismatch that favors D. geminata bloom development.

Discovery of an Isothiazolinone-Containing Antitubercular Natural Product Levesquamide

Antitubercular agent levesquamide is a new polyketide-nonribosomal peptide (PK-NRP) hybrid marine natural product isolated from Streptomyces sp. RKND-216. The structure contains a rare isothiazolinone moiety which has only been reported in collismycin SN. Structure elucidation by NMR spectroscopy was a significant challenge due to a deficiency of protons in this aromatic moiety. Therefore, the genome of Streptomyces sp. RKND-216 was sequenced to identify the levesquamide biosynthetic gene cluster (BGC). Analysis of the BGC provided structural insights and guided stable-isotope labeling experiments, which led to the assignment of the fused pyridine-isothiazolinone moiety. The BGC and the labeling experiments provide further insights into the biosynthetic origin of isothiazolinones. Levesquamide exhibited antimicrobial activity in the microplate alamarBlue assay (MABA) and low oxygen recovery assay (LORA) against Mycobacterium tuberculosis H37Rv with minimum inhibitory concentration (MIC) values of 9.65 and 22.28 μM, respectively. Similar activity was exhibited against rifampicin- and isoniazid-resistant M. tuberculosis strains with MIC values of 9.46 and 9.90 μM, respectively. This result suggests levesquamide has a different mode of action against M. tuberculosis compared to the two first-line antitubercular drugs rifampicin and isoniazid. Furthermore, levesquamide shows no cytotoxicity against the Vero cell line, suggesting it may have a useful therapeutic window.

Halogenated Bianthrones From Penicillium roseopurpureum: a Fungal Endophyte of the Marine Alga Petalonia fascia

An extract of the fungus Penicillium roseopurpureum (KP1-135C) isolated from the marine alga Petalonia fascia showed selective antimicrobial activity against Staphylococcus aureus and Mycobacterium tuberculosis H37Ra. Bioassay-guided fractionation revealed that three halogenated bianthrones, neobulgarone D, neobulgarone E, and neobulgarone F, were responsible for the observed activity of the extract. The stereochemistry of the neobulgarones was unambiguously assigned based on polarimetric data and the analysis of 1H-nuclear magnetic resonance data obtained for the three bianthrones.

Isolation of Antibiotic 3R,5R-Dihydroxyhexanoate Polymers From Endophytic Fungi

The extracts of two isolates in our library of fungal endophytes, Annulohypoxylon multiforme (TC2-046) from the medicinal plant Juniperus communis and a sterile filamentous isolate (KP1-131DD) from the marine alga Scytosiphon lomentaria, displayed similar antimicrobial bioactivity profiles with notable high activity against Staphylococcus aureus. Bioassay-guided fractionation led to the isolation of poly(3 R,5 R-dihydroxyhexanoic acid) oligomers ranging from the trimer to the 29-mer that exhibited significant and selective inhibition of S. aureus and Mycobacterium tuberculosis H37Ra in vitro.

The X-ray Crystal Structures of Ambraketal and 8-Epi-Ambraketal

The crystal structures of ambraketal and 8- epi-ambraketal, synthesised in five steps from (–)-sclareol, are reported.

Chromone Studies. Part 11.1 Synthesis and Electron-Impact Mass Spectrometric Study of Granulosin and Side-Chain Analogues

Granulosin, a chromone constituent of the bark of Galipea granulosa, and four analogues, all of which exhibit toxicity to the brine shrimp Artemia salina, have been prepared from 2′,3′,4′-trihydroxyacetophenone. High-resolution mass spectrometric analysis has permitted elucidation of the fragmentation patterns exhibited by these systems following electron-impact ionisation.

Preliminary investigations into the synthesis and antimicrobial activities of boron-containing capsaicinoids

This preliminary study reports on the synthesis of two new boron-capsaicin derivatives containing either a short or long chain aliphatic tail group using an iridium catalyzed hydroboration reaction with pinacolborane. The boronate ester groups reside on the terminal position of the tail group and are necessary for the bioactivity of these compounds. Indeed, both compounds showed considerable activity against two Gram-positive bacteria, including Vancomycin-resistant Enterococcus. Vancomycin is considered the last resort medication for the treatment of septicemia, and new antibacterial agents that can treat sepsis are of paramount importance. The more lipophilic boron compound with the longer aliphatic chain also showed antifungal activity against Saccharomyces cerevisiae.

Antibiotic Mycotoxins from an Endophytic Fusarium acuminatum Isolated from the Medicinal Plant Geum macrophyllum

An extract of the endophytic fungus Fusarium acuminatum (TC2-084) isolated from the Canadian medicinal plant Geum macrophyllum exhibited significant antimycobacterial activity against Mycobacterium tuberculosis H37Ra when fermented in both malt extract and potato dextrose broths. However, significant differences observed in the NMR spectra of the respective extracts led us to further investigate both. Bioassay guided fractionation revealed that lateropyrone was solely responsible for the bioactivity observed when TC2-084 was fermented in malt extract broth, while the antimycobacterial activity of the extract derived from the isolate fermented in potato dextrose broth was augmented by the presence of enniatins B, B1, and B4 in addition to lateropyrone.

Seasonal and environmental influences on recruitment patterns and habitat usage among resident and transient fishes in a World Heritage Site subtropical estuary

This study investigated whether the fish communities inhabiting shallow non-vegetated habitats in two divergent bays in a subtropical World Heritage Site estuarine system differed according to wet (spring-summer) and dry (autumn-winter) seasons or polyhaline and mesohaline zones, within the broader objective of facilitating spatio-temporal management. Species richness (total of 74 taxa; total length, L_T  = 11-552 mm) and abundance (51 109 individuals) were mostly greater in the wet than dry season and in polyhaline than mesohaline areas. There was a major effect of rainfall on recruitment, particularly among transient fishes, which could be the result of enhanced survival of young via greater productivity (food resources) and protection from predators (via turbidity reducing visual cues). Salinity had strong interactive effects with rainfall and temperature in one bay, with greater species richness and overall abundances as well as large abundances of four key species [Anchoa januaria and Atherinella brasiliensis (pelagic residents), Cetengraulis edentulus (pelagic transient) and Diapterus rhombeus (demersal transient)] during the wet season in polyhaline areas; possibly reflecting a biodiversity hotspot that might be affected by distance to the estuary mouth and convergence hydrology. Regionally, the results support enforcing spatio-temporal restrictions to minimize anthropogenic activities within statutory (but not always enforced) protected areas. Globally, the data reiterate the need to identify and understand biotic and abiotic effects on estuarine ichthyofaunal distributions and abundances as a precursor to their management.

Determining the mode of action of anti-mycobacterial C17 diyne natural products using expression profiling: evidence for fatty acid biosynthesis inhibition

Background

The treatment of microbial infections is becoming increasingly challenging because of limited therapeutic options and the growing number of pathogenic strains that are resistant to current antibiotics. There is an urgent need to identify molecules with novel modes of action to facilitate the development of new and more effective therapeutic agents. The anti-mycobacterial activity of the C17 diyne natural products falcarinol and panaxydol has been described previously; however, their mode of action remains largely undetermined in microbes. Gene expression profiling was therefore used to determine the transcriptomic response of Mycobacterium smegmatis upon treatment with falcarinol and panaxydol to better characterize the mode of action of these C17 diynes.

Results

Our analyses identified 704 and 907 transcripts that were differentially expressed in M. smegmatis after treatment with falcarinol and panaxydol respectively. Principal component analysis suggested that the C17 diynes exhibit a mode of action that is distinct to commonly used antimycobacterial drugs. Functional enrichment analysis and pathway enrichment analysis revealed that cell processes such as ectoine biosynthesis and cyclopropane-fatty-acyl-phospholipid synthesis were responsive to falcarinol and panaxydol treatment at the transcriptome level in M. smegmatis. The modes of action of the two C17 diynes were also predicted through Prediction of Activity Spectra of Substances (PASS). Based upon convergence of these three independent analyses, we hypothesize that the C17 diynes inhibit fatty acid biosynthesis, specifically phospholipid synthesis, in mycobacteria.

Conclusion

Based on transcriptomic responses, it is suggested that the C17 diynes act differently than other anti-mycobacterial compounds in M. smegmatis, and do so by inhibiting phospholipid biosynthesis.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-016-2949-y) contains supplementary material, which is available to authorized users.

Antimycobacterial triterpenes from the Canadian medicinal plant Sarracenia purpurea

ETHNOPHARMACOLOGICAL RELEVANCE

The purple pitcher plant, Sarracenia purpurea, is a medicinal plant used by the Canadian First Nations to treat a wide variety of illnesses. The Mi'kmaq and Wolastoqiyik (Maliseet) peoples of Eastern Canada have traditionally used infusions of S. purpurea for the treatment of tuberculosis-like symptoms. Previous investigations have shown methanolic extracts of S. purpurea to possess antimycobacterial activity.

AIM OF THE STUDY

To isolate and identify antimycobacterial constituents from S. purpurea.

MATERIALS AND METHODS

Methanolic extracts of S. purpurea were subjected to bioassay guided fractionation using the microplate resazurin assay (MRA) to assess inhibitory activity against Mycobacterium tuberculosis strain H37Ra. The antimycobacterial constituents were identified by NMR, MS and polarimetry.

RESULTS

The triterpenes betulinaldehyde, β-sitosterol, betulinic acid, and ursolic acid were isolated from S. purpurea. Betulinaldehyde, betulinic acid, and ursolic acid exhibited MICs of 450, 950, and 450μM and IC50s of 98, 169, and 93μM against M. tuberculosis H37Ra respectively whilst β-sitosterol was inactive (MIC and IC50 of >1000μM).

CONCLUSIONS

Betulinaldehyde, betulinic acid, and ursolic acid were identified as the principal constituents responsible for the antimycobacterial activity of S. purpurea. This work is consistent with the ethnopharmacological use of S. purpurea by Canadian First Nations as a treatment against infectious diseases.

Dibenz[b,f]oxepin and Antimycobacterial Chalcone Constituents of Empetrum nigrum

Two new dibenz[b,f]oxepins, empetroxepins A and B (1 and 2), and seven known compounds (3-9) were isolated from an extract of the Canadian medicinal plant Empetrum nigrum that significantly inhibited the growth of Mycobacterium tuberculosis H37Ra. The structures of 1 and 2 were established through analysis of NMR and MS data. The antimycobacterial activity of the plant extract was attributed primarily to the presence of two chalcone derivatives (6 and 7) that exhibited selective antimycobacterial activity (IC50 values of 23.8 and 32.8 μM, respectively) in comparison to mammalian (HEK 293) cells (IC50 values of 109 and 249 μM, respectively).

Antimicrobial and antimycobacterial activities of aliphatic amines derived from vanillin

Ten lipophilic amines were prepared from the reductive amination of vanillin and the corresponding primary amines using sodium borohydride in methanol. All compounds have been obtained elementally pure and an X-ray diffraction study on the 4-n-butylaniline derivative has confirmed the molecular structure. Whilst the overall antibiotic activity of the derivatives was low, some of these compounds, particularly the boronate ester 2-methoxy-4-((2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenylamino)methyl)phenol (7), showed a promising degree of antimycobacterial activity against Mycobacterium tuberculosis H37Ra, where activity seemed to vary by the position of the boron substitution on the aniline ring.

Antimycobacterial Natural Products from Endophytes of the Medicinal Plant Aralia nudicaulis

Antimycobacterial extracts of a Penicillium sp. (isolate HL4-159-41B) and a Coniothyrium sp. (isolate HL6-097-027B) isolated from the rhizomes of the Canadian medicinal plant Aralia nudicaulis were found to contain palitantin (1) and botrallin (2), craterellin C (3), mycosporulone (4), spiromassaritone (5), and massarigenin D (6) respectively. Bioassays against Mycobacterium tuberculosis H37Ra revealed that 1 - 4 possess moderate antimycobacterial activity.

Isolation of Phomopsolide A and 6(E)-Phomopsolide A as Antimycobacterial Natural Products from an Unidentified Endophyte of the Canadian Medicinal Plant Heracleum maximum

An extract of an unidentified endophyte from the Canadian medicinal plant Heracleum maximum exhibited a unique metabolomic profile and significant antimycobacterial activity against Mycobacterium tuberculosis H37Ra. Bioassay guided fractionation of the extract led to the isolation of phomopsolide A (1) and 6(E)-phomopsolide A (2). This is the first report of antimycobacterial activity for 1 and 2.

Antimycobacterial Natural Products from Endophytes of the Medicinal Plant Aralia nudicaulis

Antimycobacterial extracts of a Penicillium sp. (isolate HL4-159-41B) and a Coniothyrium sp. (isolate HL6-097-027B) isolated from the rhizomes of the Canadian medicinal plant Aralia nudicaulis were found to contain palitantin (1) and botrallin (2), craterellin C (3), mycosporulone (4), spiromassaritone (5), and massarigenin D (6) respectively. Bioassays against Mycobacterium tuberculosis H37Ra revealed that 1-4 possess moderate antimycobacterial activity.

Polyketides from an Endophytic Aspergillus fumigatus Isolate Inhibit the Growth of Mycobacterium tuberculosis and MRSA

The crude extract of Aspergillusfumigatus isolate AF3-093A, an endophyte of the brown alga Fucus vesiculosus, showed significant antimicrobial activity in initial bioactivity screens. Bioassay-guided fractionation of the extract led to the isolation of flavipin, chaetoglobosin A and chaetoglobosin B, all of which inhibited the growth of Staphylococcus aureus, methicillin-resistant S. aureus and Mycobacterium tuberculosis H37Ra. The antimycobacterial activity of these compounds has not been previously reported.

Polyketides from an Endophytic Aspergillus fumigatus Isolate Inhibit the Growth of Mycobacterium tuberculosis and MRSA

The crude extract of Aspergillus fumigatus isolate AF3-093A, an endophyte of the brown algaFucus vesiculosus, showed significant antimicrobial activity in initial bioactivity screens. Bioassay-guided fractionation of the extract led to the isolation of flavipin, chaetoglobosin A and chaetoglobosin B, all of which inhibited the growth of Staphylococcus aureus, methicillin-resistant S. aureus and Mycobacterium tuberculosis H37Ra. The antimycobacterial activity of these compounds has not been previously reported.

Deoxypodophyllotoxin isolated from Juniperus communis induces apoptosis in breast cancer cells

The study of anticancer properties from natural products has regained popularity as natural molecules provide a high diversity of chemical structures with specific biological and medicinal activity. Based on a documented library of the most common medicinal plants used by the indigenous people of North America, we screened and isolated compounds with anti-breast cancer properties from Juniperus communis (common Juniper). Using bioassay-guided fractionation of a crude plant extract, we identified the diterpene isocupressic acid and the aryltetralin lignan deoxypodophyllotoxin (DPT) as potent inducers of caspase-dependent programmed cell death (apoptosis) in malignant MB231 breast cancer cells. Further elucidation revealed that DPT, in contrast to isocupressic acid, also concomitantly inhibited cell survival pathways mediated by the MAPK/ERK and NFκB signaling pathways within hours of treatment. Our findings emphasize the potential and importance of natural product screening for new chemical entities with novel anticancer activities. Natural products research complemented with the wealth of information available through the ethnobotanical and ethnopharmacological knowledge of the indigenous peoples of North America can provide new candidate entities with desirable bioactivities to develop new cancer therapies.

Anti-mycobacterial triterpenes from the Canadian medicinal plant Alnus incana

ETHNOPHARMACOLOGICAL RELEVANCE

Alnus incana, commonly known as the gray or speckled alder, is a medicinal plant used by some Canadian First Nations to treat symptoms associated with tuberculosis. The aim of this study was to assess the anti-mycobacterial activity of an Alnus incana bark extract and to identify the active constituents of the extract.

MATERIALS AND METHODS

Methanolic extracts of the bark of A. incana were subjected to bioassay guided fractionation using Mycobacterium tuberculosis (H37Ra). The active constituents were identified by NMR and MS.

RESULTS

Four pentacyclic lupane triterpenes were isolated and were identified as betulin, betulinic acid, betulone and lupenone. Betulin displayed a MIC of 12.5 μg/mL and an IC50 of 2.4 μg/mL against M. tuberculosis (H37Ra). Betulinic acid and betulone showed lower anti-mycobacterial activities with IC50 values of 84 and 57 μg/mL respectively. Lupenone was inactive against M. tuberculosis (H37Ra).

CONCLUSIONS

Betulin, betulinic acid and betulone were identified as the major anti-mycobacterial constituents in the bark of A. incana and the functionality at carbons 3 and 28 of the lupane skeleton would seem to be important in determining the anti-mycobacterial activity of the triterpenes. This work supports the ethnopharmacological use of A. incana by Canadian First Nations communities as a treatment for tuberculosis.

Anti-mycobacterial activities of copper(II) complexes. Part II. Lipophilic hydroxypyridinones derived from maltol

Eight lipophilic 3-hydroxy-4-pyridinones have been prepared from a microwave-mediated reaction along with the corresponding copper(II) complexes. All complexes have been obtained elementally pure and X-ray diffraction studies on two of the copper complexes have confirmed the structure of these compounds. Some of these complexes showed a promising degree of anti-mycobacterial activity against Mycobacterium tuberculosis, where activity seemed to vary by substitution at the pyridinone nitrogen atom.

Intra-population trends in the maturation and reproduction of a temperate marine herbivore Girella elevata across latitudinal clines

Latitudinal variation in the reproductive characteristics of a temperate marine herbivore, rock blackfish Girella elevata, was examined from three regions of the south-eastern Australian coast. Biological sampling covered 780 km of coastline, including the majority of the species distribution. The sampling range incorporated three distinct oceanographic regions of the East Australian Current, a poleward-flowing western boundary current of the Southern Pacific Gyre and climate-change hotspot. Girella elevata are a highly fecund, group synchronous (multiple batch)-spawner. Mean fork length (L_F ) and age at maturity were greater for females than males within all regions, with both male and female G. elevata of the southern region maturing at a greater size and age than those from the central region. Estimates of batch fecundity (F_B ) were greatest in the northern and southern regions, relative to the central region where growth rates were greatest. Significant positive relationships were observed between F_B and L_F , and F_B and total fish mass. Gonado-somatic indices indicated latitudinal synchrony in spawning seasonality between G. elevata at higher latitudes, spawning in the late austral spring and summer. A late or prolonged spawning period is evident for G. elevata from the northern region. Juvenile recruitment to intertidal rock pools within the central and southern regions was synchronous with the spawning season, however, no juveniles were found within the northern region. The implications of latitudinal variation in reproductive characteristics are discussed in the context of climate and oceanographic conditions of south-east Australia.

Isolation of (–)–Avenaciolide as the Antifungal and Antimycobacterial Constituent of a Seimatosporium sp. Endophyte from the Medicinal Plant Hypericum perforatum

An extract of Seimatosporium sp., an endophyte from the Canadian medicinal plant Hypericum perforatum, exhibited significant antifungal and antimycobacterial activity against Candida albicans and Mycobacterium tuberculosis H37Ra. Bioassay guided fractionation led to the isolation of (-)–avenaciolide as the only bioactive constituent of the extract. This is the first report of both the antimycobacterial activity of avenaciolide and its isolation from a Seimatosporium sp. fungus.

Isolation of (-)-avenaciolide as the antifungal and antimycobacterial constituent of a Seimatosporium sp. Endophyte from the medicinal plant Hypericum perforatum

An extract of Seimatosporium sp., an endophyte from the Canadian medicinal plant Hypericum perforatum, exhibited significant antifungal and antimycobacterial activity against Candida albicans and Mycobacterium tuberculosis H37Ra. Bioassay guided fractionation led to the isolation of (-)-avenaciolide as the only bioactive constituent of the extract. This is the first report of both the antimycobacterial activity of avenaciolide and its isolation from a Seimatosporium sp. fungus.

Optimisation of the microplate resazurin assay for screening and bioassay-guided fractionation of phytochemical extracts against Mycobacterium tuberculosis

INTRODUCTION

Because of increased resistance to current drugs, there is an urgent need to discover new anti-mycobacterial compounds for the development of novel anti-tuberculosis drugs. The microplate resazurin assay (MRA) is commonly used to evaluate natural products and synthetic compounds for anti-mycobacterial activity. However, the assay can be problematic and unreliable when screening methanolic phytochemical extracts.

OBJECTIVE

To optimise the MRA for the screening and bioassay-guided fractionation of phytochemical extracts using Mycobacterium tuberculosis H37Ra.

METHODS

The effects of varying assay duration, resazurin solution composition, solvent (dimethyl sulphoxide - DMSO) concentration and type of microtitre plate used on the results and reliability of the MRA were investigated. The optimal bioassay protocol was applied to methanolic extracts of medicinal plants that have been reported to possess anti-mycobacterial activity.

RESULTS

The variables investigated were found to have significant effects on the results obtained with the MRA. A standardised procedure that can reliably quantify anti-mycobacterial activity of phytochemical extracts in as little as 48 h was identified. The optimised MRA uses 2% aqueous DMSO, with an indicator solution of 62.5 µg/mL resazurin in 5% aqueous Tween 80 over 96 h incubation.

CONCLUSION

The study has identified an optimal procedure for the MRA when used with M. tuberculosis H37Ra that gives rapid, reliable and consistent results. The assay procedure has been used successfully for the screening and bioassay-guided fractionation of anti-mycobacterial compounds from methanol extracts of Canadian medicinal plants.

Microsatellite primers for Australian recreationally and commercially important estuarine fishes

Eight primer sets that amplify microsatellite DNA loci were developed for the estuarine fishes, dusky flathead Platycephalus fuscus and sand whiting Sillago ciliata, which are targets of recreational and commercial fishers on the east coast of Australia. Surveys across these loci revealed remarkably similar levels of genetic diversity within samples of c. 22 P. fuscus and S. ciliata from each of the two estuaries. These loci will be useful in determining the genetic stock structure of these two species.

Isolation of the Plant Hormone (+)-Abscisic acid as an Antimycobacterial Constituent of the Medicinal Plant Endophyte Nigrospora sp

An extract of the endophytic fungus Nigropsora sp. (isolate TC2-054) from the Canadian medicinal plant Fragaria virginiana exhibited significant antimycobacterial activity against Mycobacterium tuberculosis H37Ra. Bioassay guided fractionation revealed that linoleic acid derivatives and the plant hormone (+)-abscisic acid (ABA) were responsible for the observed antimycobacterial activity. This activity of ABA has not been previously reported.

Isolation of the plant hormone (+)-abscisic acid as an antimycobacterial constituent of the medicinal plant endophyte Nigrospora sp

An extract of the endophytic fungus Nigropsora sp. (isolate TC2-054) from the Canadian medicinal plant Fragaria virginiana exhibited significant antimycobacterial activity against Mycobacterium tuberculosis H37Ra. Bioassay guided fractionation revealed that linoleic acid derivatives and the plant hormone (+)-abscisic acid (ABA) were responsible for the observed antimycobacterial activity. This activity of ABA has not been previously reported.

Isolation and bioassay screening of medicinal plant endophytes from eastern Canada

Eighty-one distinct fungal endophytes were isolated from 12 traditionally used medicinal plants from New Brunswick, Canada. This is the first report of endophytes from 8 of the 12 host plants. One hundred and sixty-two crude extracts derived from the mycelia and spent fermentation broths of liquid cultures of each endophyte were screened for antibacterial and antifungal activity. Twenty-two extracts were active against Staphylococcus aureus while 30 were active against Pseudomonas aeruginosa. Twelve crude extracts were found to be active against Candida albicans.

Anti-mycobacterial activities of copper(II) salicylaldimine complexes derived from long-chain aliphatic amines

Twelve copper(II) Schiff base complexes derived from lipophilic amines have been prepared using either salicylaldehyde or ortho-vanillin via a microwave-assisted reaction. All complexes have been obtained elementally pure and an X-ray diffraction of an isopentyl derivative has confirmed the structure of these compounds. All complexes showed a promising degree of anti-mycobacterial activity against Mycobacterium tuberculosis, where activity seemed to increase with an increase in the length of the aliphatic chain.

The Canadian medicinal plant Heracleum maximum contains antimycobacterial diynes and furanocoumarins

ETHNOPHARMACOLOGICAL RELEVANCE

Heracleum maximum is amongst the most commonly used plants by the indigenous peoples of North America. The First Nations of the eastern Canada use infusions of Heracleum maximum roots for the treatment of respiratory ailments including tuberculosis. Previous investigations of extracts derived from the roots of Heracleum maximum have shown it to possess antimycobacterial activity.

AIM OF THE STUDY

To isolate and identify antimycobacterial constituents from the roots of Heracleum maximum.

MATERIALS AND METHODS

A methanolic extract of Heracleum maximum roots was subjected to bioassay guided fractionation using the microplate resazurin assay (MRA) to assess inhibitory activity against Mycobacterium tuberculosis strain H37Ra. The antimycobacterial constituents were identified by NMR, MS and polarimetry.

RESULTS

The polyacetylene (3R,8S)-falcarindiol and the furanocoumarins bergapten, isobergapten, angelicin, sphondin, pimpinellin, isopimpinellin and 6-isopentenyloxyisobergapten were isolated from the Heracleum maximum root extract. (3R,8S)-Falcarindiol and 6-isopentenyloxyisobergapten exhibited MICs of 24 μM and 167 μM and IC50s of 6 μM and 27 μM against Mycobacterium tuberculosis H37Ra respectively. The remaining furanocoumarins bergapten, isobergapten, angelicin, sphondin, pimpinellin, and isopimpinellin were less active, with MICs of 925, 1850, 2149, 1859, 812 and 1625 μM and IC50s of 125, 344, 350, 351, 389 and 406 μM.

CONCLUSIONS

(3R,8S)-Falcarindiol, bergapten, isobergapten, angelicin, sphondin, pimpinellin, isopimpinellin and 6-isopentenyloxyisobergapten were identified as the principal constituents responsible for the antimycobacterial activity of the roots of Heracleum maximum. This work supports the ethnopharmacological use of Heracleum maximum by Canadian First Nations and Native American communities as a treatment for infectious diseases, specifically tuberculosis.

Antimicrobials from the Marine Algal Endophyte Penicillium sp

An endophytic fungus identified as Penicillium sp. was isolated from the brown alga Fucus spiralis collected from the Shetland Islands, United Kingdom. Bioassay-guided fractionation of an extract of the fungus led to the isolation of cladosporin, epiepoformin, phyllostine, and patulin, all of which showed antimicrobial activity against either Staphylococcus aureus or Pseudomonas aeruginosa. Cladosporin has not previously been identified from a fungus of the genus Penicillium, and, despite being biosynthetically related, epiepoformin, phyllostine and patulin have not been previously reported from one source.

Antimicrobials from the marine algal endophyte Penicillium sp

An endophytic fungus identified as Penicillium sp. was isolated from the brown alga Fucus spiralis collected from the Shetland Islands, United Kingdom. Bioassay-guided fractionation of an extract of the fungus led to the isolation of cladosporin, epiepoformin, phyllostine, and patulin, all of which showed antimicrobial activity against either Staphylococcus aureus or Pseudomonas aeruginosa. Cladosporin has not previously been identified from a fungus of the genus Penicillium, and, despite being biosynthetically related, epiepoformin, phyllostine and patulin have not been previously reported from one source.

The invasion inhibitor sarasinoside A1 reverses mesenchymal tumor transformation in an E-cadherin-independent manner

During metastatic progression, an aberrant epithelial-to-mesenchymal transformation (EMT) that is most often driven by the loss of the cell-cell adhesion molecule E-cadherin generates noncohesive tumor cells that are highly invasive. We used mesenchymally transformed, E-cadherin-negative MDA-MB-231 breast carcinoma cells in a natural product screen and determined that the triterpenoid saponin sarasinoside A1 inhibited their invasion and the invasion of a number of other tumor cell lines. Sarasinoside A1 also caused MDA-MB-231 cells to become cohesive in a three-dimensional basement membrane and collagen gel cultures. In two-dimensional culture, sarasinoside A1 initiated a morphologic re-epithelialization of MDA-MB-231 cells wherein preexisting nonepithelial cadherins and the junction-associated proteins β-catenin and ZO-1 all relocalized to sites of cell-cell contact. In addition, the intercellular space between neighboring cells narrowed considerably, the stability of polymerized actin at cell-cell contact sites increased, and there was a recruitment and stabilization of nectin-based adhesion complexes to these sites, all of which strongly suggested that functional cell-cell junctions had formed. Importantly, sarasinoside A1 induced nascent cell-cell junction formation that did not require changes in gene expression and was not associated with an induction of E-cadherin but resulted in increased activation of Rap GTPases. Therefore, our findings with sarasinoside A1 suggest that it may be possible to re-epithelialize metastatic tumor cells with phenotypic consequence even when E-cadherin is completely absent.

Synthesis, characterization, and bioactivities of platinum(II) complexes bearing pyridinecarboxaldimines containing aliphatic groups

Condensation of 2-pyridinecarboxaldehyde with six primary amines containing aliphatic groups gave the corresponding pyridinecarboxaldimines (N-N′R). Addition of these ligands to [PtCl2(coe)]2 (coe = cis-cyclooctene) gave complexes of the type cis-PtCl2(N-N′R) (1: R = propyl, 2: R = hexyl, 3: R = octyl, 4: R = nonyl, 5: R = hexadecyl, and 6: R = octadecyl) in moderate yields. The molecular structure of the hexyl derivative (2) has been confirmed by an X-ray diffraction study. Crystals of 2 were triclinic with a = 8.6858(19) Å, b = 8.7567(19) Å, c = 9.5080(19) Å, α = 76.546(3)°, β = 87.151(3)°, and γ = 78.586(3)° in the space group P1. All platinum complexes show considerable anti-bacterial and anti-mycobacterial properties.

Anti-mycobacterial natural products from the Canadian medicinal plant Juniperus communis

ETHNOPHARMACOLOGICAL RELEVANCE

Common juniper, Juniperus communis, is amongst the plants most frequently used by the indigenous peoples of North America for medicinal purposes. The First Nations of the Canadian Maritimes use infusions of juniper primarily as a tonic and for the treatment of tuberculosis. Previous investigations of extracts derived from the aerial parts of J. communis have shown it to possess anti-mycobacterial activity. The aim of the study is to isolate and identify anti-mycobacterial constituents from the aerial parts of J. communis.

MATERIALS AND METHODS

Methanolic extracts of J. communis needles and branches were subjected to bioassay guided fractionation using the microplate resazurin assay (MRA) to assess inhibitory activity against Mycobacterium tuberculosis strain H37Ra. The anti-mycobacterial constituents were identified by NMR, MS and polarimetry.

RESULTS

The diterpenes isocupressic acid and communic acid and the aryltetralin lignan deoxypodophyllotoxin were isolated from the J. communis extract. Isocupressic acid and communic acid (isolated as an inseparable 3:2 mixture of cis and trans isomers) displayed MICs of 78 μM and 31 μM and IC(50)s of 46 μM and 15 μM against M. tuberculosis H37Ra respectively. Deoxypodophyllotoxin was less active, with a MIC of 1004 μM and an IC(50) of 287 μM.

CONCLUSIONS

Isocupressic acid, communic acid and deoxypodophyllotoxin were identified as the principal constituents responsible for the anti-mycobacterial activity of the aerial parts of J. communis. Although further research will be required to evaluate the relative activities of the two communic acid isomers, this work validates an ethnopharmacological use of this plant by Canadian First Nations and Native American communities.

Anti-mycobacterial diynes from the Canadian medicinal plant Aralia nudicaulis

ETHNOPHARMACOLOGICAL RELEVANCE

Aralia nudicaulis, or wild sarsaparilla, is used as a traditional medicinal plant for the treatment of various illnesses by many of the Canadian First Nations. Iroquois and Algonquin First Nations of Eastern Canada use a tea prepared from dried Aralia nudicaulis rhizome as a cough medicine and for the treatment of tuberculosis. Previous investigations of aqueous extracts of Aralia nudicaulis rhizomes have shown it to possess antimycobacterial activity.

AIM OF THE STUDY

To isolate and identify antimycobacterial constituents from Aralia nudicaulis rhizomes.

MATERIALS AND METHODS

Methanolic extracts of Aralia nudicaulis rhizomes were subjected to bioassay guided fractionation using the microplate resazurin assay (MRA) to assess inhibitory activity against Mycobacterium tuberculosis strain H37Ra. The antimycobacterial constituents were identified by NMR, MS and polarimetry.

RESULTS

Two C17 polyacetylenes with significant antimycobacterial activity were isolated from the Aralia nudicaulis rhizome extract. The polyacetylenes were identified as (3R)-falcarinol and (3R, 9R, 10S)-panaxydol. Falcarinol and panaxydol displayed MICs of 25.6μM and 36.0μM and IC(50)s of 15.3μM and 23.5μM against Mycobacterium tuberculosis H37Ra.

CONCLUSIONS

Falcarinol and panaxydol were identified as the principal constituents responsible for the antimycobacterial activity of Aralia nudicaulis rhizomes validating an ethnopharmacological use of this plant by the Canadian First Nations.

Antimycobacterial screening of traditional medicinal plants using the microplate resazurin assay

Multidrug-resistant Mycobacterium tuberculosis strains have rapidly become a global health concern. North American First Nations communities have used traditional medicines for generations to treat many pulmonary infections. In this study, we evaluated the antimycobacterial activity of 5 medicinal plants traditionally used as general therapeutics for pulmonary illnesses and specifically as treatments for tuberculosis. Aqueous extracts of Aralia nudicaulis, Symplocarpus foetidus, Heracleum maximum, Juniperus communis, and Acorus calamus were screened for antimycobacterial activity against Bacillus Calmette-Guérin, Mycobacterium avium, and M. tuberculosis H37Ra using the colorimetric microplate resazurin assay. Extracts of Acorus calamus and H. maximum root demonstrated significant antimycobacterial activity comparable to that of the rifampin control (2 microg/mL). Evaluation of the cytotoxicity of these 2 extracts using the MTT assay also showed that the extracts were less toxic to 3 human cell lines than was the DMSO positive control. This study demonstrates that aqueous extracts of the roots of H. maximum and Acorus calamus possess strong in vitro antimycobacterial activity, validates traditional knowledge, and provides potential for the development of urgently needed novel antituberculous therapeutics.

Absence of regulatory IL-10 enhances innate protection against filarial parasites by a neutrophil-independent mechanism

Brugia malayi causes the major tropical disease, lymphatic filariasis. Chronicity of disease is associated with generation of regulatory cells secreting IL-10 and/or TGF-beta. Previous work has shown that the rate of microfilariae (Mf) clearance from the blood is mouse strain-dependent. Here, we show that IL-10 plays an important role in preventing the clearance of Mf. Indeed, anti-IL-10 antibody treatment increases the rate of Mf clearance from the bloodstream in both rapid-Mf-clearing CBA/Ca and slow-clearing C57Bl/6 mice. In addition, IL-10(-/-) mice implanted intraperitoneally with Mf-producing adult nematodes have significantly lower Mf, but not adults, in comparison with wild-type mice at 3 weeks post-implantation (p.i.). Clearance of Mf from the peritoneal cavity of IL-10(-/-) mice is associated with a dramatic infiltration of neutrophils. Furthermore, rapid-Mf-clearing CBA/Ca mice have a dramatic blood neutrophilia at 24 h p.i., whereas slow-clearing C57Bl/6 mice show no such neutrophilia. Thus, neutrophils may play a role as effector cells in microfilarial infection. We therefore treated mice with anti-granulocyte antibody to abolish neutrophil recruitment during Mf infection i.v. Although anti-granulocyte treatment severely depleted neutrophils, it did not significantly reduce the rate of B. malayi Mf clearance either during primary infection or during a challenge following antigen sensitization.