1,721,049 research outputs found
Enhancement of a pentacyclic tyrosine kinase inhibitor production in Cladosporium cf. cladosporioides by Cladosporol
Full text linkThe binaphthyl derivative cladosporol A was
supplied from 60 to 200 mg l−1 to shaken cultures of Cladosporium cf. cladosporioides. Compared to blank, fungal
biomass was not affected by adding cladosporol till 100 mg l−1: it rather increased at higher ratios between 150
and 200 mg l−1. The production of the major pentacyclic metabolite 1, a cytokine production and tyrosine kinase inhibitor, was enhanced tenfold when cladosporol was
supplied at the highest ratio (200 mg l−1) to shaken growing cultures of the fungus. The bioconversion of cladosporol to cladosporol D through reductive cleavage of the epoxide group was also observed. Interest in this kind of metabolites lies in their potential activity vs DNA topoisomerase I
Characterization of new aza-sesquiterpenoids from the fungus Clavicorona Divaricata
No full textMushrooms have proved to be a rich source of secondary metabolites with unusual structures as well as interesting biological activities. Despite their potential for drug development, few bioactive metabolites have been reported from mushrooms as compared with higher plants and microbes. In our screening project on bioactive metabolites of Basidiomycetes we have investigated the metabolites produced by the fungus Clavicorona divaricata in MPG agar cultures and isolated divaricatine A and B together with the nor-sesquiterpenoids tsugicoline L and M. Successively, the fermentation of the fungus in different conditions, gave rise to complex mixtures, from which new aza-sesquiterpenoids were isolated. The poster describes the isolation, structure elucidation and absolute configuration assessment of these novel metabolites The skeleton of these compounds was never found before among the sequiterpenes of protoilludane origin. A possible mechanism of their formation is also suggested.
The new metabolites showed a weak antibacterial activity against Bacillus cereus and Sarcinea lutea (50μg/disc), and inhibited the growth of Lepidum sativum (After 48 h, the inhibition of the root elongation was 85, 91 and 72%, respectively)
Isolation and structure elucidation of new sesquiterpenes of protoilludane origin from the fungus Clavicorona divaricata
No full textFour novel sesquiterpenes of protoilludane origin, divaricatines A 3a and B 3b, 7-epitsugicoline H 4a and tsugicoline M 5a have been isolated from agar cultures of the fungus Clavicorona divaricata (Basidiomycetes). Their structures were elucidated by means of NMR studies and chemical correlations. All the metabolites are weakly active on bacteria but inhibited the germination of the water cress Lepidium sativum. A possible mechanism of their formation from the protoilludane tsugicoline A 1 is suggested. A fifth metabolite, the norsesquiterpene tsugicoline L 2b, was also isolated from the same fungus together with the known tsugicoline I 2a
A synthetic approach to sporotricale methylether
No full textA synthetic approach to sporotricale methylether, a metabolite of the fungus Sporotrichum laxum with inhibitory activity against Helicobacter pylori, is described. The synthesis relies on the condensation of 13-hydroxy-10-oxotetradecanal, prepared via reaction of a sulfone-activated moiety with valerolactone, with diethyl 3,5-dimethoxyphthalide-7-phosphonate
A novel secondary metabolite from the Eucalyptus pathogen Mycosphaerella cryptica
Full text linkThe most abundant metabolite of the eucalyptus leaf spot pathogen Mycosphaerella cryptica was
extracted from agar cultures. The structure of the compound was elucidated by detailed studies of
NMR and MS data and by comparison with derivatives. The compound is a previously undescribed
diphenylether structurally related to pannaric acid found in lichens. Culture extracts from another
species of Mycosphaerella isolated from the same environment yielded 5-hydroxymethylfuran-
3-carboxylic acid, a furan acidic compound previously isolated from a basidiomycete fungus. Assays
for bioactivity of these metabolites revealed no evidence for antimicrobial activity. Some phytotoxicity
was seen on newly emerged leaves of Eucalyptus globulus, but not on juvenile or adult leaves, when
treated with either metabolite
Cryphonectric acid and other minor metabolites from a hypovirulent strain of Cryphonectria parasitica
Full text linkInvestigations carried out on secondary metabolites produced in culture by a hypovirulent strain of Cryphonectria parasitica allowed the isolation of several compounds which were characterized by NMR analysis and derivatization reactions. The most abundant metabolite was a new compound, called cryphonectric acid (1). Other metabolites were diaporthin, the only known phytotoxic compound isolated from both virulent and hypovirulent strains of C. parasitica, (+)-orthosporin, and L-p-hydroxyphenyllactic acid (HOPLA). Root growth activity of the purified compounds was evaluated both on tomato seedlings and maize subapical segments
Isolation and structure elucidation of aza-sesquiterpenoids of protoilludane origin formed by shaken cultures of the fungus Clavicorona divaricata
No full textTwo novel sesquiterpenes of protoilludane origin, the alkaloids divaricatine C and D, have been isolated
from MPGB shaken cultures of the fungus Clavicorona divaricata (Basidiomycetes). Their structures were
elucidated by means of NMR studies and chemical correlations. The metabolites were weakly active
against bacteria and inhibited the germination of the water cress Lepidium sativum. A possible
mechanism of their formation from the protoilludane tsugicoline A (2) is suggested
Acremines H–N, novel prenylated polyketide metabolites produced by a strain of Acremonium byssoides
Full text linkFive novel metabolites, acremines H–N, have been isolated from malt extract–peptone–glucose agar
cultures of a strain of Acremonium byssoides. Their structures and stereochemistry were elucidated using
a combination of 13C and 1H homo and heteronuclear 2D NMR experiments. Acremines H–N inhibited
the germination of sporangia of Plasmopara viticola
Synthesis of (+)-Spirolaxine Methyl Ether
No full textA short and efficient synthesis of (+)-spirolaxine methyl ether, a metabolite of the fungus Sporotrichum laxum with inhibitory activity against Helicobacter pylori, is described. The synthesis has been carried out by a Prins cyclization, to obtain the [6,5]-spiroketal system, and a Wadsworth-Emmons condensation, applied for the installation of the polymethylene chain on the phthalide moiety
Concavine, an unusual diterpenic alkaloid produced by the fungus Clitocybe concava
No full textA novel alkaloid with an unprecedented ring system consisting of a dodecahydro-7-oxa-9a-aza-benzo[a]azulene ring (1), has been isolated from cultures of Clitocybe concava (Basidiomycetae). Its structure and relative stereochemistry were elucidated on the basis of spectroscopic data. Concavine presents a weak antibacterial activity
- …
