Depsidones from Talaromyces stipitatus SK-4, an endophytic fungus of the mangrove plant Acanthus ilicifolius

An endophytic fungus (Talaromyces stipitatus SK-4) was isolated from the leaves of a mangrove plant Acanthus ilicifolius. Its crude extract exhibited significant antibacterial activity and was purified to afford two new depsidones, talaromyones A and B (1 and 2), along with five known depsidone analogs (3–7). Their structures, including absolute configuration, were elucidated through extensive spectroscopic data analysis and modified Mosher's method. Compound 2 showed antibacterial activity against Bacillus subtilis with an MIC value of 12.5 μg/mL. In the inhibitory assay against α-glucosidase, compounds 2, 4 and 5 displayed moderate activities with IC₅₀ values ranging from 48.4 to 99.8 μM.     

Floral scent analysis in Hieracium subgenus Pilosella and its taxonomical implications

Species-rich Hieracium subgen. Pilosella is well-known for a high degree of endemism and infra-specific differentiation including many subspecies (“microspecies”) of very restricted distribution. In Hieracium subgen. Pilosella floral scents of 27 predominantly Bavarian species, mostly of Hieracium calodon, H. zizianum and H. densiflorum, are investigated here. Floral scent compositions were studied by GC-MS analysis of dynamic headspace samples. Altogether, 56 floral scent compounds were identified, mainly benzenoids, fatty acid derivatives, monoterpenes, homoterpenes and sesquiterpenes. The chemical patterns were found to be taxon-specific and are thus of taxonomical value. The data support some rearrangements at subspecific level, such as the inclusion of H. bauhini subsp. hispidissimum in H. densiflorum. These rearrangements are supported by morphological data. The traditional species concepts, however, are mostly corroborated by our scent data.     

Affinities of Phylacia and the daldinoid Xylariaceae, inferred from chemotypes of cultures and ribosomal DNA sequences

A chemotaxonomic evaluation using hplc profiling was undertaken to resolve the infrageneric and intergeneric affinities of over 150 strains of Xylariaceae. Daldinia placentiformis, Hypoxylon nicaraguense, H. polyporus, and Phylacia sagrana were found to contain 8-methoxy-1-naphthol, which is apparently absent in Annulohypoxylon, Hypoxylon, and related genera with bipartite stromata. D. placentiformis and other species of Daldinia and Entonaema produced this naphthol, 5-hydroxy-2-methylchromone, isosclerone derivatives, and ‘AB-5046’ phytotoxins. Phylacia sagrana differed from most Daldinia spp., except for D. caldariorum, by producing eutypine derivatives in addition to the above compounds. Indolylquinones were observed in H. nicaraguense and H. polyporus. Isosclerones were also identified in the A. multiforme complex, but Hypoxylon and other Annulohypoxylon and most Hypoxylon spp. studied Annulohypoxylon spp. contained 5-methylmellein as the major metabolite of their cultures. Based on the occurrence of the above metabolites, further mellein-type dihydroisocoumarins, teleomorphic and anamorphic Xylariaceae with Nodulisporium-like anamorphs (‘Hypoxyloideae’) were divided into various chemotypes. A comparison of their 5.8S/ITS nuc-rDNA sequences agreed in some important aspects with the above results: H. nicaraguense and H. polyporus appeared basal to a clade comprising Daldinia, Entonaema, and Ph. sagrana. The latter species appeared allied to D. caldariorum, but was distantly related to Pyrenomyxa morganii and Hypoxylon s. str.