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Typ III Polyketidsynthasen bilden eine Vielzahl von strukturell vielfältigen Naturstoffen durch die Verwendung unterschiedlichster Starter- und Extendersubstrate. Zu diesen gehören die Benzophenon- und Biphenylsynthasen. Benzophenonsynthasen bilden mithilfe der C6 ? C1 Claisen-Kondensation 2, 4, 6 Trihydroxybenzophenon. Dies ist die Vorstufe der Xanthone, wovon einige gegen Morbus Alzheimer wirken. Biphenylsynthasen bilden mithilfe der C2 ? C7 Aldol-Kondensation 3, 5 Dihydroxybiphenyl. Biphenyle und die verwandten Dibenzofurane sind die Phytoalexine des Rosaceae-Untertribus Malinae. In dieser Arbeit ist es gelungen, eine neuartige bifunktionelle Polyketidsynthase aus Hypericum polyphyllum zu isolieren und zu charakterisieren. Diese katalysiert sowohl die Claisen- als auch die Aldol-Kondensation in einem Reaktionsansatz. Sie ist die erste bekannte Polyketidsynthase, die 2, 4, 6-Trihydroxybenzophenon und 3, 5 Dihydroxybiphenyl in äquimolaren Mengen bilden kann. Es konnte gezeigt werden, dass die Inkubationstemperatur einen entscheidenden Einfluss auf die Produktbildung hat. Durch Doppelmutanten ist es gelungen, die Fähigkeit der 3, 5 Dihydroxybiphenyl-Bildung zu eliminieren ohne die Bildung von 2, 4, 6 Trihydroxybenophenon zu dezimieren.

Premise of the study: The clusioid clade includes five families (i.e., Bonnetiaceae, Calophyllaceae, Clusiaceae s.s., Hypericaceae, and Podostemaceae) represented by 94 genera and ~1900 species. Species in this clade form a conspicuous element of tropical forests worldwide and are important in horticulture, timber production, and pharmacology. We conducted a taxon-rich multigene phylogenetic analysis of the clusioids to clarify phylogenetic relationships in this clade. METHODS: We analyzed plastid (matK, ndhF, and rbcL) and mitochondrial (matR) nucleotide sequence data using parsimony, maximum likelihood, and Bayesian inference. Our combined data set included 194 species representing all major clusioid subclades, plus numerous species spanning the taxonomic, morphological, and biogeographic breadth of the clusioid clade. Key results: Our results indicate that Tovomita (Clusiaceae s.s.), Harungana and Hypericum (Hypericaceae), and Ledermanniella s.s. and Zeylanidium (Podostemaceae) are not monophyletic. In addition, we place four genera that have not been included in any previous molecular study: Ceratolacis, Diamantina, and Griffithella (Podostemaceae), and Santomasia (Hypericaceae). Finally, our results indicate that Lianthus, Santomasia, Thornea, and Triadenum can be safely merged into Hypericum (Hypericaceae). CONCLUSIONS: We present the first well-resolved, taxon-rich phylogeny of the clusioid clade. Taxon sampling and resolution within the clade are greatly improved compared to previous studies and provide a strong basis for improving the classification of the group. In addition, our phylogeny will form the foundation for our future work investigating the biogeography of tropical angiosperms that exhibit Gondwanan distributions.

Garcinia section Xanthochymus (Clusiaceae) is revised for Thailand with four native species, i.e ., G. dulcis , G. nervosa , G. prainiana , and G. xanthochymus . All species are described with updated morphological descriptions, illustrations, and an identification key, together with notes on distributions, distribution maps, habitats and ecology, phenology, conservation assessments, etymology, vernacular names, uses, and specimens examined. Four taxa, G. andamanica , G. andamanica var. pubescens , G. cambodgiensis and G. vilersiana , are synonymized under G. dulcis , and two taxa, G. nervosa var. pubescens and G. spectabilis , are newly synonymized under G. nervosa . Nine names are lectotypified: G. dulcis and its associated synonyms ( G. cambodgiensis and G. vilersiana ), G. nervosa and its associated synonyms ( G. andersonii , G. nervosa var. pubescens , and G. spectabilis ), G. prainiana , and G. xanthochymus . All species have a conservation assessment of Least Concern (LC). The fruits of all species are edible and have a sour or sweet-sour taste.

Garcinia sections Dicrananthera and Macrostigma (Clusiaceae) is revised for Thailand. Three species are enumerated, i.e., one species, G. thorelii belongs to the section Dicrananthera, and two species, G. nuntasaenii and G. prainiana , are in the section Macrostigma. Detailed morphological descriptions and illustrations are provided, together with notes on distribution, habitats and ecology, phenology, conservation assessments, etymology, vernacular names, uses, and specimens examined. An identification key to the species of section Macrostigma is presented. One name, G. thorelii , is lectotypified here. For Garcinia nuntasaenii we recommend a conservation status of Endangered [EN B2ab(v)] and for the other two species ( G. prainiana and G. thorelii ) a conservation status of Least concern [LC]. A number of vegetative characters and features of reproductive organs, especially the flowers, distinguish the two sections and we enumerate these herein.

During the review of the Brazilian species of Lorostemon (Clusiaceae), we verified that some specimens previously reported as L. bombaciflorus Ducke for South Guyana and the Brazilian Eastern Amazonia belong to a species still unknown to science. Here, we provide a description, taxonomic comments, illustrations, and a distribution map of Lorostemon roseoviridis Fer.-Silva & L.Marinho, a new species from eastern Amazonia.

Garcinia sopsopia belongs to the section Brindonia in the family Clusiaceae. The fruits, young shoots and leaves are edible and have a sour taste. Morphological description and illustrations are provided, along with notes on distribution, habitats and ecology, phenology, a preliminary conservation assessment, etymology, vernacular names, uses and specimens examined. Garcinia mckeaniana is a newly-synonymised name under G. sopsopia . Three synonyms of G. sopsopia are here lectotypified, including G. paniculata , G. rhumicowa and G. mckeaniana .

Garcinia section Garcinia (Clusiaceae) is revised for Thailand with three species and one variety, i.e., two native species: G. celebica and G. exigua , and one cultivated species: G. mangostana var. mangostana. Detailed morphological descriptions, illustrations, and an identification key to the species are presented, along with notes on distributions, habitats and ecology, phenology, conservation assessments, etymology, vernacular names, uses, and specimens examined. The section is recognized by its terminal inflorescences of simple cymes, or sometimes a solitary flower; flowers with 4 sepals and 4 petals; male flowers often with a pistillode, and stamens united into a single 4-lobed or 4-angled bundle, and with 2-thecous anthers; usually multilocular ovaries and stigmas with distinct or weak lobes and smooth or rough; and fruits with a smooth surface. Three associated synonyms of G. celebica : G. ferrea , G. basacensis , and G. hombroniana , are lectotypified here in a second-step. In Thailand, Garcinia celebica is found in a very wide variety of habitats, at elevations of 0–1,500 m amsl., and is known to be naturally distributed in all floristic regions. G. exigua is found in dry evergreen forest on limestone hills and in littoral dry evergreen forest on limestone hills, at elevations of 50–100 m amsl. in Krabi Province, the peninsular region. G. mangostana var. mangostana is found only in cultivation. Garcinia exigua has a conservation status of Vulnerable [VU B2ab(iii)] and the other two species have a conservation status of Least Concern [LC]. The fleshy pulp surrounding the seeds of two species, G. celebica and G. mangostana var. mangostana is edible and has a sweet-sour taste.

While studying specimens of Garcinia gardneriana from the Brazilian Amazon we detected problems in reconciling the morphology of these collections to that of the type-collection (with the basionym of Rheedia gardneriana ) and similar specimens from other regions of Brazil. An investigation led us to the conclusion that the Amazonian collections represent a new species, described herein as Garcinia apostoloi . We present a taxonomic treatment comprising a morphological description, a distributional map in southern Amazonia, a description of the habitat, a preliminary conservation assessment, and other taxonomic comments.

Premise of research. The clusioid clade is a member of the large rosid order Malpighiales and contains ∼1900 species in five families: Bonnetiaceae, Calophyllaceae, Clusiaceae sensu stricto (s.s.), Hypericaceae, and Podostemaceae. Despite recent efforts to clarify their phylogenetic relationships using molecular data, no such data are available for several critical taxa, including especially Hypericum ellipticifolium (previously recognized in Lianthus), Lebrunia, Neotatea, Thysanostemon, and the second-oldest rosid fossil (∼90 Ma), Paleoclusia chevalieri. Here, we (i) assess congruence between phylogenies inferred from morphological and molecular data, (ii) analyze morphological and molecular data simultaneously to place taxa lacking molecular data, and (iii) use ancestral state reconstructions (ASRs) to examine the evolution of traits that have been important for circumscribing clusioid taxa and to explore the placement of Paleoclusia. Methodology. We constructed a morphological data set including 69 characters and 81 clusioid species (or species groups). These data were analyzed individually and in combination with a previously published molecular data set of four genes (plastid matK, ndhF, and rbcL and mitochondrial matR) using parsimony, maximum likelihood (ML), and Bayesian inference. We used ML ASRs to infer the evolution of morphological characters. Pivotal results. Our phylogeny inferred from morphology alone was poorly supported but largely in agreement with molecular data. Moreover, our combined analyses were much better supported and largely confirm taxonomic hypotheses regarding relationships of extant taxa newly included here. The extinct Paleoclusia was placed as a member of stem group Clusiaceae s.s. or within crown group Clusiaceae s.s. as sister to one of its two major subclades. Conclusions. Despite poor overall bootstrap support for the placement of Paleoclusia, ancestral character state reconstructions are generally in agreement with our placements. Our recommendation is that Paleoclusia be treated as either a minimum stem group or a crown group age constraint of Clusiaceae s.s.

Two new acylphloroglucinol derivatives, 13,14-didehydroxygarcicowin C (1) and 13,14-didehydroxyisoxanthochymol (2), have been isolated from the stems of Garcinia multiflora, together with seven known compounds (3–9). The structures of new compounds 1 and 2 were elucidated by MS and extensive 1D/2D NMR spectroscopic analyses. Among the isolates, 13,14-didehydroxy-isoxanthochymol (2) and sampsonione B (3) exhibited inhibition against lipopolysaccharide (LPS)-induced NF-κB activation in macrophages at 30 μM with relative luciferase activity values (inhibitory %) of 0.75 ± 0.03 (24 ± 4%) and 0.12 ± 0.03 (88 ± 4%), respectively. Additionally, sampsonione B (3) reduced LPS-induced nitric oxide (NO) production in murine RAW264.7 macrophages and did not induce cytotoxicity against RAW 264.7 cells after 24 h treatment. Compound 3 is worth further investigation and may be expectantly developed as an anti-inflammatory drug candidate.