Biosynthesis of phenylpropanoid amides by an endophytic Penicillium brasilianum found in root bark of Melia azedarach.

Biosynthetic studies on brasiliamides, potently convulsive and bacteriostatic compounds from an endophytic Penicillium brasilianum isolated from Melia azedarach (Meliaceae), confirms their phenylpropanoid origin, which is very uncommon in fungi. Feeding experiments with [2-(13)C]- phenylalanine indicated the incorporation of two units of this amino acid on brasiliamide structures. The first step in the phenylpropanoid pathway to those compounds was evaluated through enzymatic bioassays and confirmed the phenylalanine ammonia-lyase (PAL) participation. The metabolism of phenylalanine in this fungus is discussed.

Preaustinoid A: a meroterpene produced by Penicillium sp.

THE TITLE MEROTERPENE PREAUSTINOID A (SYSTEMATIC NAME: methyl 15-hydr-oxy-2,6,6,10,13,15-hexa-methyl-17-methyl-ene-7,14,16-trioxotetra-cyclo-[11.3.1.0(2,11).0(5,10)]hepta-decane-1-car-box-yl-ate), C(26)H(36)O(6), features a fused four-ring arrangement. Three rings are in different distorted chair conformations and the other is in a distorted boat conformation. The absolute configuration was established based on [α(D)] = -4.97° (c = 1.10 g l(-1), CH(2)Cl(2)). In the crystal, the mol-ecules are connected into supra-molecular chains via O-H⋯O hydrogen bonds.

Neoaustin: a meroterpene produced by Penicillium sp.

The title meroterpene neoaustin {systematic name: (1'S,2'R,3S,7'R,9'S,11'S,12'R)-11'-hydr-oxy-2,2,2',9',12'-penta-methyl-6',15'-dimethyl-ene-2,6-dihydro-13'-oxaspiro-[pyran-3,5'-tetra-cyclo-[7.5.1.0(1,11).0(2,7)]penta-deca-ne]-6,10',14'-trione}, C(25)H(30)O(6), comprises five rings, three six-membered and two five-membered. The absolute configuration was established based on [α(D)] = +166.91° (c 1.21, CH(2)Cl(2)). In the crystal, the mol-ecules are connected into a supra-molecular helical chain via O-H⋯O hydrogen bonds reinforced by C-H⋯O contacts.

Larvicidal effects of fungal Meroterpenoids in the control of Aedes aegypti L., the main vector of dengue and Yellow fever.

The mosquito Aedes aegypti is an increasing problem of public health, being the vector responsible for dengue and Yellow Fever in tropical and subtropical regions. The aim of this work was to determine the potential larvicidal activity of a series of meroterpenoids, compounds 1-7, previously obtained fungal secondary metabolites from Penicillium sp., against the third-instar larvae of A. aegypti. The lethal concentrations (LC(50) and LC(90)) of 1-7 were evaluated 24 h after exposure. Dehydroaustin (4) was the most active meroterpenoid in the series, with an LC(50) value of 2.9 ppm, making it an attractive natural insecticide.

Meroterpenes from Penicillium sp found in association with Melia azedarach.

A Penicillium sp was isolated from the root bark of Melia azedarach and cultivated over sterilized rice. After chromatographic procedures, two meroterpenes, named preaustinoid A and B, were obtained in addition to the known alkaloid verruculogen. Their structures were identified by extensive spectroscopic studies, and they exhibited moderate bacteriostatic effects on Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Bacillus sp.

Further meroterpenes produced by Penicillium sp., an endophyte obtained from Melia azedarach.

From the methanol extract of Penicillium sp. cultivated on sterilized rice for three weeks we isolated three new meroterpenes preaustinoid A1, A2 and B1. The fungus was isolated from the root bark of Melia azedarach after surface sterilization. The structures of these compounds were identified by intensive spectroscopic studies.

Three highly oxygenated caryophyllene sesquiterpenes from Pestalotiopsis sp., a fungus isolated from bark of Pinus taeda.

A Pestalotiopis sp. was isolated from the trunk bark of Pinus taeda. The fungus was cultivated in liquid medium and produced three highly oxygenated caryophyllene sequiterpene derivatives, named pestalotiopsolide A, taedolidol and 6-epitaedolidol, respectively. The sesquiterpenes were isolated by silica gel based chromatographic procedures and their structures were elucidated by NMR spectroscopic data.

New spirorotenoids from Tephrosia candida.

The ethyl acetate extract of roots of Tephrosia candida afforded three new spirorotenoids belonging to a new class of spirocompounds, named tephrospirolactone, tephrospiroketone I, and tephrospiroketone II. The structures of these compounds were determined mainly based on spectral analysis. The only known spirorotenoid described in the literature is amorphispironone, isolated from Amorpha fruticosa.

Diclavatol and tetronic acids from Penicillium griseoroseum.

In our continuous studies on the chemistry of the endophytic fungus Penicillium griseoroseum, an endophyte isolated from fruits of Coffea arabica, we isolated clavatol, a dimethylated tetraketide, and its dimer which appears to be a novel natural compound. The studies also resulted in the identification of two known tetronic acids, viridicatic acid and terrestric acid, found in ethyl acetate and n-butanol extracts. Spectroscopic studies using 1-D and 2-D NMR and MS/MS analysis were performed to determine the structures of these compounds, first reported by this Penicillium. Two other tetronic acids congeners were identified through HPLC/MS/MS studies, based on fragmentation pattern of ions produced from ionised tetronic acids, and UV light absorptions.

Time course production of indole alkaloids by an endophytic strain of Penicillium brasilianum cultivated in rice.

During our studies concerning endophytic fungi, two indole alkaloids were co-produced with verruculogen by Penicillium brasilianum isolated from Melia azedarach (Meliaceae). The compounds were isolated by the use of combined chromatographic procedures and identified by physical methods, mainly 1D- and 2D-NMR experiments. This article also describes the production of verruculogen TR-2, first described for this species of Penicillium, and a verruculogen TR-2C-11 epimer, that is a novel fungal natural product. The kinetic production of verruculogen and verruculogen TR-2 produced by P. brasilianum were evaluated in order to understand the involvement of verruculogen TR-2 in verruculogen biosynthesis.

Oxidative potential of some endophytic fungi using 1-indanone as a substrate.

The oxidative potential of the fungus Penicillium brasilianum, a strain isolated as an endophyte from a Meliaceae plant (Melia azedarach), was investigated using 1-indanone as a substrate to track the production of monooxygenases. The fungus produced the dihydrocoumarin from 1-indanone with the classical Baeyer-Villiger reaction regiochemistry, and (-)-(R)-3-hydroxy-1-indanone with 78% ee. Minor compounds resulting from lipase and SAM activities were also detected. The biotransformation procedures were also applied to a collection of Penicillium and Aspergillus fungi obtained from M. azedarach and Murraya paniculata. The results showed that Baeyer-Villiger were mostly active in fungi isolated from M. azedarach. Almost all of the fungi tested produced 3-hydroxy-1-indanone..

Endophytic fungi as a source of biofuel precursors.

Endophytic fungi, isolated from a number of different species of tropical plants, were investigated for lipid biodiesel precursor production. The extracts produced from liquid cultures of these fungi were subjected to acidcatalyzed transesterification reactions with methanol producing methyl esters and then analyzed through chromatographic (GC-FID) and spectrometric techniques (MS, NMR ¹H). The European Standard Method, EN 14103, was used for the quantification of methyl esters extracted from the fungi of the species and genera studied. Xylariaceous fungi exhibited the highest concentrations of methyl esters (91%), and hence may be a promising source for biofuel.

Complete 1H and 13C NMR assignments of aurasperone A and fonsecinone A, two bis-naphthopyrones produced by Aspergillus aculeatus.

Complete assignments of 1H and 13C NMR chemical shifts of the polyketides aurasperone A and fonsecinone A were made by means of nuclear Overhauser enhancement and heteronuclear NMR correlation experiments. These compounds were isolated for the first time from Aspergillus aculeatus, an endophytic fungus obtained from leaves of Melia azedarach(Meliaceae).

Electron ionization mass spectral fragmentation of deoxynivalenol and related tricothecenes.

Careful analysis of the electron impact (EI) mass spectral data obtained for the trimethylsilyl (TMS) ethers of known trichothecene mycotoxins of the deoxynivalenol group permitted the construction of a database useful for the identification of these mycotoxins directly from a gas chromatography/mass spectrometry (GC/MS) run. Structures of the ions at m/z 103, 117, 147 and 191 were elucidated by high-resolution mass spectrometry (HRMS) and a fragmentation scheme was suggested. The relative abundances of these ions in the mass spectra of the trichothecenes allowed a fast structural diagnosis during analysis of biological matrices. A new mycotoxin of this group, 3-acetylnivalenol, was tentatively identified by using MS data interpretation only.