Bioactive Constituents from an Endophytic Fungus, Penicillium polonicum NFW9, Associated with Taxus fauna.

BACKGROUND: Endophytic fungi are being recognized as vital and untapped sources of a variety of structurally novel and unique bioactive secondary metabolites in the field of natural products drug discovery. Herein, this study reports the isolation and characterization of secondary metabolites from an endophytic fungus Penicillium polonicum (NFW9) associated with Taxus fuana. METHOD: The extracts of the endophytic fungus cultured on potato dextrose agar were purified using several chromatographic techniques. Biological evaluation was performed based on their abilities to inhibit tumor necrosis factor-alpha (TNF-α)-induced nuclear factor-kappa B (NF-κB) and cytotoxicity assays. RESULTS: Bioactivity-directed fractionation of the ethyl acetate extract of a fermentation culture of an endophytic fungus, Penicillium polonicum led to the isolation of a dimeric anthraquinone, (R)- 1,1',3,3',5,5'-hexahydroxy-7,7'-dimethyl[2,2'-bianthracene]-9,9',10,10'-tetraone (1), a steroidal furanoid (-)-wortmannolone (2), along with three other compounds (3-4). Moreover, this is the first report on the isolation of compound 1 from an endophytic fungus. All purified metabolites were characterized by NMR and MS data analyses. The stereo structure of compound 1 was determined by the measurement of specific optical rotation and CD spectrum. The relative stereochemistry of 2 was confirmed by single-crystal X-ray diffraction. Compounds 2-3 showed inhibitory activities in the TNF-α-induced NF-κB assay with IC50 values in the range of 0.47-2.11 µM. Compounds 1, 4 and 5 showed moderate inhibition against NF-κB and cancer cell lines. CONCLUSION: The endophytic fungus Penicillium polonicum of Taxus fuana is capable of producing biologically active natural compounds. Our results provide a scientific rationale for further chemical investigations into endophyte-producing natural products, drug discovery and development.

Isolation and characterization of a biosurfactant-producing Fusarium sp. BS-8 from oil contaminated soil.

This study reports characterization of a biosurfactant-producing fungal isolate from oil contaminated soil of Missa Keswal oil field, Pakistan. It was identified as Fusarium sp. BS-8 on the basis of macroscopic and microscopic morphology, and 18S rDNA gene sequence homology. The biosurfactant-producing capability of the fungal isolates was screened using oil displacement activity, emulsification index assay, and surface tension (SFT) measurement. The optimization of operational parameters and culture conditions resulted in maximum biosurfactant production using 9% (v/v) inoculum at 30°C, pH 7.0, using sucrose and yeast extract, as carbon and nitrogen sources, respectively. A C:N ratio of 0.9:0.1 (w/w) was found to be optimum for growth and biosurfactant production. At optimal conditions, it attained lowest SFT (i.e., 32 mN m(-1) ) with a critical micelle concentration of ≥ 1.2 mg mL(-1) . During 5 L shake flask fermentation experiments, the biosurfactant productivity was 1.21 g L(-1) pure biosurfactant having significant emulsifying index (E24 , 70%) and oil-displacing activity (16 mm). Thin layer chromatography and Fourier transform infrared spectrometric analyses indicated a lipopeptide type of the biosurfactant. The Fusarium sp. BS-8 has substantial potential of biosurfactant production, yet it needs to be fully characterized with possibility of relatively new class of biosurfactants.