[1H, 1´H-[3, 3´]Biindolyl from the terrestrial fungus Gliocladium catenulatum.

BERTINETTI B.; RODRÍGUEZ M.A.; GODEAS A.M.; CABRERA G.

JOURNAL OF ANTIBIOTICS

JAPAN ANTIBIOTICS RESEARCH ASSOC

Lugar: Tokyo; Año: 2010 vol. 63 p. 681 - 683

0021-8820

The G. catenulatum Gilman and Abbot strain was isolated from vertic soil sediments from a lettuce plantation in Las Heras, Buenos Aires, Argentina. Strains were isolated by the soil particle washing method. The antibiotic activity against P. larvae was determined by the agar diffusion method, using MPYGP-thiamine 0.01% medium. The incubations were carried out at 37 1C in 10% CO2. Oxytetracycline was used as a positive control (inhibition halo diameter: 17mm, 50 mg per disk; MIC 0.5 mg per disk). The spectroscopic data (2D NMR, HR-ESI-MS) of compounds 2 and 3 were identical to the known gliocladins A and C.In fact, there are some minor discrepancies between the NMR signal assignments of natural and synthetic gliocladin C, and our data were most similar to the synthetic variant.The antibiotic activity of the crude extracts and pure compounds 1–3 were also determined against Bacillus subtilis (ATCC 6633), Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 25922) by the agar diffusion method at 100 mg per disk and 50 mg per disk for extracts/fractions and compounds, respectively, and against the phytopathogens Fusarium virguliforme, Colletotrichum truncatum and Macrophomina phaseolina by bioautography on TLC method. All the isolated compounds and the extracts were inactive in these assays. Compound 1 has not been previously reported as a natural product, although it is known as a synthetic compound. All the spectroscopic data of 1 were in full agreement with the synthetic compound. It is noteworthy that there are a few halogenated natural 3,3¢-biindoles formerly reported, isolated from the cyanobacterium Rivularia firma15 and beetroot, Beta vulgaris. two ETP-derived compounds, 2 and 3, and 3,3¢- biindol, previously undescribed as a naturally occurring product, which has specific antibacterial activity against the honey bee enthomopathogenic bacterium P. larvae, were all isolated and identified from a culture of the fungus G. catenulatum. This is the first report of the isolation of these compounds from this species.