•The chemical constituents of the fungus Stereum sp. YMF1.04183 were investigated.•New sesquiterpenes stereumenes A, B and C were obtained.•Their structures were characterized by extensive 2D-NMR studies.The chemical constituents of the basidiomycete Stereum sp. YMF1.04183 were studied. Three new sesquiterpenes, stereumenes A–C (1–3), were isolated and identified from the EtOAc extract of Stereum sp. YMF1.04183 culture broth. Stereumene B showed weak nematicidal activity against Caenorhabditis elegans.Download high-res image (75KB)Download full-size image

•The chemical constituents of the fungus Stereum sp. YMF1.1686 were investigated.•New sesquiterpenes sterostreins R, S and T were obtained.•Their structures were characterized by extensive 2D-NMR studies.A basidiomycete fungus, Stereum sp. YMF1.1686, was studied for its ability to produce new sesquiterpenes on nutrient-enriched cultivation media. Three new sesquiterpenes sterostrein R (1), sterostrein S (2) and sterostrein T (3), along with two known compounds sterostrein A (4) and sterostrein C (5) were isolated from the EtOAc extract of a culture broth of Stereum sp. YMF1.1686.

The Actinomycete strain P294 was isolated from soil and identified as Streptomyces sp. based upon the results of 16S rRNA sequence analysis. Three compounds obtained from the solid fermentation products of this strain have been determined by 1D, 2D NMR and HRMS experiments. These compounds include two new compounds angumycinones C (1) and D (2), and the known compound X-14881 E (3). All compounds were assayed for antibacterial and nematicidal activity. The results showed the three compounds had different degrees of inhibitory activity against several target bacteria but no significant toxicity against the nematode Caenorhabditis elegans.

A bacterial strain YMF 3.175 was identified as Alcaligenes faecalis based on its 16S rRNA sequence. Seven compounds including 1,2-benzenedicarboxylic acid bis(2α-methylheptyl) ester (1), cyclo(L-Pro-L-Val) (2), cyclo(Gly-L-Pro) (3), 3-pyridinecarboxylic acid (4), cyclo(L-Pro-L-Tyr) (5), adenosine (6) and L-Val (7) were obtained from the extracts of fermentation broth of this bacterium. Their structures were elucidated on the basis of spectroscopic data. All compounds were assayed for antibacterial activity and the activity of inducing trap formation in nematophagous fungus Arthrobotrys oligospora. Compounds 1, 3 and 6 showed activity against Escherichia coli and Staphylococcus aureus. Compound 7 induced trap formation in A. oligospora.

Investigation of secondary metabolites in fermentation broth of Wautersiella falsenii YMF 3.00141 led to isolation of 5 compounds, including cyclo-(L-Pro-L-Tyr) (1), 4-phenylbutanoic acid (2), 2(1H)-quinolinone (3), 1H-indole-3-carboxaldehyde (4) and butyl-β-D-glucopyranoside (5). Each of isolated compounds was tested for nematicidal activity against Caenothabditis elegans and Meloidogyne incognita. Compounds 1, 2, 3 and 5 had low or no activity against the nematodes. Compound 4 (200 mg/L; 72 h incubation) was highly active against nematodes C. elegans and M. incognita with the mortalities 94.00 and 72.15%, respectively. This is the first study about chemical constituents of bacterium W. falsenii.