seco-Pregnane Glycosides from Australian Caustic Vine (Cynanchum viminale subsp. australe).

Cynanchum viminale subsp. australe, more commonly known as caustic vine, is a leafless succulent that grows in the northern arid zone of Australia. Toxicity toward livestock has been reported for this species, along with use in traditional medicine and its potential anticancer activity. Disclosed herein are novel seco-pregnane aglycones cynavimigenin A (5) and cynaviminoside A (6), together with new pregnane glycosides cynaviminoside B (7) and cynavimigenin B (8). Cynavimigenin B (8) contains an unprecedented 7-oxobicyclo[2.2.1]heptane moiety in the seco-pregnane series, likely arising from a pinacol-type rearrangement. Interestingly, these isolates displayed only limited cytotoxicity in cancer and normal human cell lines, in addition to low activity against acetylcholinesterase and Sarcoptes scabiei bioassays, suggesting that 5-8 are not associated with the reported toxicity of this plant species.

Genomic insights into rapid speciation within the world's largest tree genus Syzygium.

Species radiations, despite immense phenotypic variation, can be difficult to resolve phylogenetically when genetic change poorly matches the rapidity of diversification. Genomic potential furnished by palaeopolyploidy, and relative roles for adaptation, random drift and hybridisation in the apportionment of genetic variation, remain poorly understood factors. Here, we study these aspects in a model radiation, Syzygium, the most species-rich tree genus worldwide. Genomes of 182 distinct species and 58 unidentified taxa are compared against a chromosome-level reference genome of the sea apple, Syzygium grande. We show that while Syzygium shares an ancient genome doubling event with other Myrtales, little evidence exists for recent polyploidy events. Phylogenomics confirms that Syzygium originated in Australia-New Guinea and diversified in multiple migrations, eastward to the Pacific and westward to India and Africa, in bursts of speciation visible as poorly resolved branches on phylogenies. Furthermore, some sublineages demonstrate genomic clines that recapitulate cladogenetic events, suggesting that stepwise geographic speciation, a neutral process, has been important in Syzygium diversification.

Antimicrobial Benzyltetrahydroisoquinoline-Derived Alkaloids from the Leaves of Doryphora aromatica.

Four new alkaloids, (R)-nomimantharine trifluoroacetate (2), 12-demethylphaeantharine trifluoroacetate (3), nominanthranal trifluoroacetate (4), and the enolic form of 1-hydroxy-6,7-dimethoxy-2-methylisoquinoline trifluoroacetate (5), together with the known dimeric alkaloid phaeantharine trifluoroacetate (1), have been isolated from the extract of the leaves of the rainforest tree Doryphora aromatica (Monimiaceae). The structures of these compounds were elucidated by HRMS and 1D and 2D NMR data. (R)-Nomimantharine trifluoroacetate (2) contains an ether linkage connecting a benzylisoquinoline unit with a tetrahydroisoquinoline, a novel class of dimeric alkaloid. The absolute configuration of (R)-nomimantharine trifluoroacetate (2) was established via electronic circular dichroism data. The compounds isolated were subjected to in vitro antimicrobial assays against a panel of pathogenic microorganisms, including Mycobacterium smegmatis, M. tuberculosis, Escherichia coli, Staphylococcus aureus (SA), and five clinical isolates of oxacillin/methicillin-resistant S. aureus (MRSA). Phaeantharine trifluoroacetate (1) and (R)-nomimantharine trifluoroacetate (2) showed moderate inhibitory activities against Mycobacteria and MRSA strains.

A Grand Challenge. 3. Unbiased Phenotypic Function of Metabolites from Australia Plants Gloriosa superba and Alangium villosum against Parkinson's Disease.

As part of a continuing research program aiming to identify chemical probes to interrogate Parkinson's disease (PD), we have investigated the Australian plants Gloriosa superba and Alangium villosum. The chemical investigations of G. superba resulted in the isolation of four new alkaloids, ß-lumicolchicosides A-C (1-3) and γ-lumicolchicoside A (4), together with four lumicolchicine derivatives (5-8) and six colchicine analogues (9-14) as known structures. The chemical investigations of A. villosum resulted in the isolation of four new benzoquinolizidine N-oxides, tubulosine Nß5-oxide (15), isotubulosine Nα5-oxide (16), 9-demethyltubulosine Nß5-oxide (17), and 9-demethylisotubulosine Nα5-oxide (18), together with five known benzoquinolizidine alkaloids (19-23). The chemical structures of the new compounds (1-4 and 15-18) were characterized unambiguously by extensive analysis of their NMR and MS data. Unbiased multidimensional profiling was used to investigate the phenotypic profiles of all of the metabolites. The results show that the lead probes have different effects on cellular organelles that are implicated in PD in patient-derived cells.

Exploring cycad foliage as an archive of the isotopic composition of atmospheric nitrogen.

Molecular nitrogen (N2 ) constitutes the majority of Earth's modern atmosphere, contributing ~0.79 bar of partial pressure (pN2 ). However, fluctuations in pN2 may have occurred on 107 -109  year timescales in Earth's past, perhaps altering the isotopic composition of atmospheric nitrogen. Here, we explore an archive that may record the isotopic composition of atmospheric N2 in deep time: the foliage of cycads. Cycads are ancient gymnosperms that host symbiotic N2 -fixing cyanobacteria in modified root structures known as coralloid roots. All extant species of cycads are known to host symbionts, suggesting that this N2 -fixing capacity is perhaps ancestral, reaching back to the early history of cycads in the late Paleozoic. Therefore, if the process of microbial N2 fixation records the δ15 N value of atmospheric N2 in cycad foliage, the fossil record of cycads may provide an archive of atmospheric δ15 N values. To explore this potential proxy, we conducted a survey of wild cycads growing in a range of modern environments to determine whether cycad foliage reliably records the isotopic composition of atmospheric N2 . We find that neither biological nor environmental factors significantly influence the δ15 N values of cycad foliage, suggesting that they provide a reasonably robust record of the δ15 N of atmospheric N2 . Application of this proxy to the record of carbonaceous cycad fossils may not only help to constrain changes in atmospheric nitrogen isotope ratios since the late Paleozoic, but also could shed light on the antiquity of the N2 -fixing symbiosis between cycads and cyanobacteria.

Nomenclatural changes in Coleus and Plectranthus (Lamiaceae): a tale of more than two genera.

A synopsis of the genera Coleus Lour, Equilabium A.J.Paton, Mwany. & Culham and Plectranthus L'Hér. (Lamiaceae, Tribe Ocimeae, Subtribe Plecranthinae) is presented. Generic delimitation follows a recently published molecular phylogeny which identified Coleus as the sister of the remaining genera of Subtribe Plectranthinae; Plectranthus as sister to Tetradenia Benth. and Thorncroftia N.E.Br., and a separate phylogenetically distinct genus Equilabium comprising species previously placed in Plectranthus. In this treatment, 294 species of Coleus, 42 of Equilabium, and 72 of Plectranthus are recognized. All but one of the combinations in Equilabium are new as only the genus and type species have been previously published. Two-hundred and twelve names are changed to combinations in Coleus from Plectranthus, Pycnostachys Hook. and Anisochilus Benth.

Using UHPLC-MS Profiling for the Discovery of New Dihydro-ß-Agarofurans from Australian Celastraceae Plant Extracts.

An analytical method using UHPLC-MS was developed and applied to 16 crude CH2Cl2 extracts from Australian Celastraceae plants; the endemic plant materials were accessed from Griffith University's NatureBank resource and included bark, fruit, leaf, root, twig and mixed samples, all of which were collected from Queensland, Australia. The generated UHPLC-MS data were analysed and dereplicated using the scientific databases Dictionary of Natural Products and SciFinder Scholar in order to potentially identify new dihydro-ß-agarofurans from local Celastraceae plants. These investigations led to the large-scale extraction and isolation work on a prioritised fruit sample that belonged to the rainforest plant Denhamia celastroides. Chemical investigations resulted in the purification of four new natural products, denhaminols O⁻R (1⁻4), along with the related and known compound, denhaminol G (5). The structures of all the new compounds were determined via detailed analysis of NMR and MS data.

Alkaloid diversity in the leaves of Australian Flindersia (Rutaceae) species driven by adaptation to aridity.

The genus Flindersia (Rutaceae) comprises 17 species of mostly Australian endemic trees. Although most species are restricted to rainforests, four have evolved to grow in semi-arid and arid environments. In this study, the leaf alkaloid diversity of rainforest and semi-arid/arid zone adapted Australian Flindersia were compared by LC/MS-MS and NMR spectroscopy. Contrary to expectations, Flindersia alkaloid diversity was strongly correlated with environmental aridity, where species predominating in drier regions produced more alkaloids than their wet rainforest congenerics. Rainforest species were also more chemically similar to each other than were the four semi-arid/arid zone species. There was a significant relationship between the presence of alkaloid structural classes and phylogenetic distance, suggesting that alkaloid profiles are influenced by both genetic and environmental factors. The results suggest that the radiation of Flindersia species out of the rainforest and into drier environments has promoted the evolution of unique alkaloid diversity. Plants growing in arid and semi-arid regions of Australia may represent an untapped source of undescribed specialised metabolites.

5,6,7,3',4',5'-Hexamethoxyflavone from the Australian plant Eremophila debilis (Myoporaceae).

The aerial parts of the endemic Australian plant Eremophila debilis (Myoporaceae) contain 3% dry weight of the biologically active 5,6,7,3',4',5'-hexamethoxyflavone, which had its structured confirmed using X-ray crystal crystallography. The presence of significant levels of the polypharmacologically active 5,6,7,3',4',5'-hexamethoxyflavone in the edible parts of the plant has potential implications for its use as a food and bush medicine.

Lignans from the Australian Endemic Plant Austrobaileya scandens.

The sole species of the vascular plant family Austrobaileyaceae, Austrobaileya scandens, is endemic to the tropical rainforest of northeastern Queensland, Australia. A single lead-like enhanced fraction of A. scandens showed potent inhibition against human prostate cancer PC3 cells. Chemical investigation of this plant resulted in the isolation of two new aryltetralin lignans, austrobailignans 8 and 9 (1 and 2), and the synthetic compound nicotlactone B (3), newly identified as a natural product together with nine known lignans (4-12). Their structures were established on the basis of spectroscopic analyses. Absolute configurations of the new compounds were determined by quantum chemical electronic circular dichroism (ECD) calculations employing time-dependent density functional theory. The ECD calculations were also used to assign the absolute configuration of marphenol K (4) and revise the absolute configuration of kadsurindutin C (20). Ten out of the 12 isolated compounds inhibited the growth of PC3 cells with IC50 values ranging from micromolar to nanomolar. Marphenol A (5) was found for the first time to induce apoptosis and arrest the S cell cycle phase of PC3 cells.

Patterns of Phylogenetic Diversity of Subtropical Rainforest of the Great Sandy Region, Australia Indicate Long Term Climatic Refugia.

Australia's Great Sandy Region is of international significance containing two World Heritage areas and patches of rainforest growing on white sand. Previous broad-scale analysis found the Great Sandy biogeographic subregion contained a significantly more phylogenetically even subset of species than expected by chance contrasting with rainforest on white sand in Peru. This study aimed to test the patterns of rainforest diversity and relatedness at a finer scale and to investigate why we may find different patterns of phylogenetic evenness compared with rainforests on white sands in other parts of the world. This study focussed on rainforest sites within the Great Sandy and surrounding areas in South East Queensland (SEQ), Australia. We undertook field collections, expanded our three-marker DNA barcode library of SEQ rainforest plants and updated the phylogeny to 95% of the SEQ rainforest flora. We sampled species composition of rainforest in fixed area plots from 100 sites. We calculated phylogenetic diversity (PD) measures as well as species richness (SR) for each rainforest community. These combined with site variables such as geology, were used to evaluate patterns and relatedness. We found that many rainforest communities in the Great Sandy area were significantly phylogenetically even at the individual site level consistent with a broader subregion analysis. Sites from adjacent areas were either not significant or were significantly phylogenetically clustered. Some results in the neighbouring areas were consistent with historic range expansions. In contrast with expectations, sites located on the oldest substrates had significantly lower phylogenetic diversity (PD). Fraser Island was once connected to mainland Australia, our results are consistent with a region geologically old enough to have continuously supported rainforest in refugia. The interface of tropical and temperate floras in part also explains the significant phylogenetic evenness and higher than expected phylogenetic diversity.

Coconut Laurels: The Leaf Essential Oils from Four Endemic Australian Cryptocarya Species: C. bellendenkerana, C. cocosoides, C. cunninghamii and C. lividula (Lauraceae).

The leaf oils of four species of Cryptocarya, endemic to Australia, were examined. These species are known colloquially as 'coconut laurels' due to the purported distinctive aroma from the crushed foliage. C. cocosoides produced an oil in which bicyclogermacrene (3-26%), spathulenol (16-47%), massoia lactone (6-pentyl-5,6-dihydro-2H-pyran-2-one) (11-15%), (6-heptyl-5,6-dihydro-2H-pyran-2-one (0.3-3%) and benzyl benzoate (0.2-5%) were the principal components. C. cunninghamii showed a second chemotype to that previously published, with benzyl benzoate (80.2%) being the principal component. C. bellendenkerana gave a leaf oil in which the major components were the terpenes limonene (8.3%), ß-phellandrene (11.8%) and viridiflorene (9.1%). The principal components of the leaf oil of C. lividula were bicyclogermacrene (26.1%), spathulenol (21.1%) and ß-eudesmol (6.1%). Benzaldehyde and acetophenone were both present in amounts of less than 0.7%. Only C. cocosoides and C. cunninghamii have been found to have a 'coconut' aroma mainly due to the presence of massoia lactone and homologues.

Bioaffinity Mass Spectrometry Screening.

Electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICR-MS or ESI-FTMS) was used to screen 192 natural product extracts and a 659-member natural product-based fragment library for bindings to a potential malaria drug target, Plasmodium falciparum Rab11a (PfRab11a, PF13_0119). One natural product extract and 11 fragments showed binding activity. A new natural product, arborside E, was identified from the active extract of Psydrax montigena as a weak binder. Its binding activity and inhibitory activity against PfRab11a were confirmed by ESI-FTMS titration experiments and an orthogonal enzyme assay.

Tyrosyl-DNA Phosphodiesterase I Inhibitors from the Australian Plant Macropteranthes leichhardtii.

Mass-directed isolation of the CH2Cl2/MeOH extract from the bark of an Australian plant, Macropteranthes leichhardtii, resulted in the purification of a new phenylpropanoid glucoside, macropteranthol (1), together with four known analogues (2-5). The structure of compound 1 was elucidated by NMR and MS data analyses and quantum chemical calculations. Compounds 3 and 5 showed inhibitory activity against tyrosyl-DNA phosphodiesterase I with IC50 values of ∼1.0 µM.

Mapping biodiversity and setting conservation priorities for SE Queensland's rainforests using DNA barcoding.

Australian rainforests have been fragmented due to past climatic changes and more recently landscape change as a result of clearing for agriculture and urban spread. The subtropical rainforests of South Eastern Queensland are significantly more fragmented than the tropical World Heritage listed northern rainforests and are subject to much greater human population pressures. The Australian rainforest flora is relatively taxonomically rich at the family level, but less so at the species level. Current methods to assess biodiversity based on species numbers fail to adequately capture this richness at higher taxonomic levels. We developed a DNA barcode library for the SE Queensland rainforest flora to support a methodology for biodiversity assessment that incorporates both taxonomic diversity and phylogenetic relationships. We placed our SE Queensland phylogeny based on a three marker DNA barcode within a larger international rainforest barcode library and used this to calculate phylogenetic diversity (PD). We compared phylo- diversity measures, species composition and richness and ecosystem diversity of the SE Queensland rainforest estate to identify which bio subregions contain the greatest rainforest biodiversity, subregion relationships and their level of protection. We identified areas of highest conservation priority. Diversity was not correlated with rainforest area in SE Queensland subregions but PD was correlated with both the percent of the subregion occupied by rainforest and the diversity of regional ecosystems (RE) present. The patterns of species diversity and phylogenetic diversity suggest a strong influence of historical biogeography. Some subregions contain significantly more PD than expected by chance, consistent with the concept of refugia, while others were significantly phylogenetically clustered, consistent with recent range expansions.

Major clades of Australasian Rutoideae (Rutaceae) based on rbcL and atpB sequences.

BACKGROUND: Rutaceae subfamily Rutoideae (46 genera, c. 660 species) is diverse in both rainforests and sclerophyll vegetation of Australasia. Australia and New Caledonia are centres of endemism with a number of genera and species distributed disjunctly between the two regions. Our aim was to generate a high-level molecular phylogeny for the Australasian Rutoideae and identify major clades as a framework for assessing morphological and biogeographic patterns and taxonomy. METHODOLOGY/PRINCIPAL FINDINGS: Phylogenetic analyses were based on chloroplast genes, rbcL and atpB, for 108 samples (78 new here), including 38 of 46 Australasian genera. Results were integrated with those from other molecular studies to produce a supertree for Rutaceae worldwide, including 115 of 154 genera. Australasian clades are poorly matched with existing tribal classifications, and genera Philotheca and Boronia are not monophyletic. Major sclerophyll lineages in Australia belong to two separate clades, each with an early divergence between rainforest and sclerophyll taxa. Dehiscent fruits with seeds ejected at maturity (often associated with myrmecochory) are inferred as ancestral; derived states include woody capsules with winged seeds, samaras, fleshy drupes, and retention and display of seeds in dehisced fruits (the last two states adaptations to bird dispersal, with multiple origins among rainforest genera). Patterns of relationship and levels of sequence divergence in some taxa, mostly species, with bird-dispersed (Acronychia, Sarcomelicope, Halfordia and Melicope) or winged (Flindersia) seeds are consistent with recent long-distance dispersal between Australia and New Caledonia. Other deeper Australian/New Caledonian divergences, some involving ant-dispersed taxa (e.g., Neoschmidia), suggest older vicariance. CONCLUSIONS/SIGNIFICANCE: This comprehensive molecular phylogeny of the Australasian Rutoideae gives a broad overview of the group's evolutionary and biogeographic history. Deficiencies of infrafamilial classifications of Rutoideae have long been recognised, and our results provide a basis for taxonomic revision and a necessary framework for more focused studies of genera and species.

Multiple metal accumulation within a manganese-specific genus.

PREMISE OF THE STUDY: Plants that strongly accumulate metals may be practically beneficial, and also serve as novel resources for increasing fundamental understanding of plant biology. Australian Gossia (Myrtaceae) species are delineated by a conspicuous affinity for the heavy metal manganese (Mn), which is a micronutrient crucial to photosynthesis. This genus includes several Mn hyperaccumulators such as G. bidwillii. Unusually, in G. bidwillii foliar Mn is most highly concentrated in photosynthetic cells, an observation thus far restricted to foliar-Mn accumulation in Mn hyperaccumulators. Recent discovery that several of these Gossia species accumulate other metals in addition to Mn will enable investigation as to whether primary sequestration of metals in photosynthetic tissues is restricted to Mn. METHODS: Gossia species known to accumulate nickel (Ni) or aluminum (Al) in addition to Mn were sampled in the field. Complementary proton- and electron-probe data were combined to evaluate in vivo microdistribution patterns of excessively accumulated foliar metals. KEY RESULTS: It was discovered that in addition to Mn and Ni, Gossia fragrantissima accumulated foliar zinc (Zn) and cobalt (Co), with Mn, Ni, and Co most highly localized in mesophyll cells and Zn primarily located in the upper epidermis. In G. hillii, Mn and Al were highly concentrated in the palisade and epidermis, respectively. CONCLUSIONS: This investigation provides evidence that the primary disposal of excess foliar metals in photosynthetic cells is not exclusive to Mn. It offers rare intrageneric perspective on metal compartmentation, pointing to significant variation among tonoplastal metal transporters associated with detoxification.

Watsonianone A-C, anti-plasmodial ß-triketones from the Australian tree, Corymbia watsoniana.

Three new ß-triketones, watsonianones A-C, and the known compound corymbone B were isolated from the flowers of the Australian eucalypt Corymbia watsoniana. Watsonianone A is the first naturally occurring methylene bridged bis-tetramethylcyclohexatrione, watsonianone B is only the fourth fused bisfurano ß-triketone and watsonianone C is the first 4,4a,9,9a-tetrahydro-2H-xanthene-1,3,5,7(6H,8H)-tetraone to be reported in the literature. MS and NMR analysis established the structures of the new compounds. All three new compounds showed anti-plasmodial activity against chloroquine resistant (Dd2) and sensitive strains (3D7) of the parasite, Plasmodium falciparum, responsible for malarial infections. Watsonianone B was the most potent inhibitor (IC(50) 0.289 µM vs. Pf 3D7) demonstrating significant selectivity against the human cell line, HEK 293 (>400 ×). Stage specificity studies indicate that watsonianone B is predominantly active against young ring stages of P. falciparum.

Climate predictions accelerate decline for threatened macrozamia cycads from queensland, australia.

Changes in the potential habitat of five allopatric species of threatened Macrozamia cycads under scenarios of increased ambient temperature were examined. A lack of seed dispersal, poor recruitment, low seedling survival, obligate pollinator mutualisms and continued habitat loss have led to extant populations being largely restricted to refugia. Models predict that the area of suitable habitat will further contract and move upslope, resulting in a reduced incidence within protected areas with increasing annual mean temperature. Areas of potential habitat for all five species are also predicted to become increasingly isolated from one another, further reducing the exchange between metapopulations and subpopulations, exacerbating existing threatening processes.

Chemical composition and cytotoxicity of oils and eremophilanes derived from various parts of Eremophila mitchellii Benth. (Myoporaceae).

A detailed investigation of the wood, leaf, branch and root oil of Eremophila mitchellii (Benth.) was carried out by a combination of GC-FID, GC-MS and NMR. The wood oil was composed predominantly of eremophilanes, a rare class of biologically active, bicyclic sesquiterpenoids. The root oil was also found to contain the eremophilanes together with the zizaene sesquiterpene, sesquithuriferone. 9-Hydroxy-1,7(11),9-eremophilatrien-8-one and the known 1(10),11-eremophiladien-9-one (eremophilone), 9-hydroxy-7(11),9-eremophiladien-8-one (2-hydroxyeremophilone), 8-hydroxy-11-eremophilen-9-one (santalcamphor), 8-hydroxy-10,11-eremophiladien-9-one, sesquithuriferone and 8-hydroxy-1,11-eremophiladien-9-one were purified and elucidated by NMR. Three approaches to the purification of the major eremophilanes from the wood oil are described. (+) Spathulenol, α-pinene, globulol, viridiflorene were the major constituents of the leaf oil. All of the essential oils and the eremophilanes exhibited cytotoxicity against P388D(1) mouse lymphoblast cells in-vitro.