Lawsozaheer, a new chromone produced by an endophytic fungus Paecilomyces variotii isolated from Lawsonia Alba Lam. inhibits the growth of Staphylococcus aureus.

One new chromone, lawsozaheer (1), and five known compounds 4-(2-hydroxyethyl) phenol (2), viriditoxin (3), stigmasta-4,6,8(14),22-tetraen-3-one (4), ß-sitosterol (5) and stigmasterol (6) were isolated from the fungal broth of Paecilomyces variotii. Their structures were elucidated using spectroscopic data. The configuration of 1 was determined by Horeau's method. The broth extract and compound 1 showed highly selective activity against Staphylococcus aureus (NCTC 6571) bacterium with 83.19 and 84.26% inhibition respectively at 150 µg/mL, comparing well with that of standard drug ofloxacin (87.013% inhibition at 100 µg/mL). Broth extract also showed 75, and 40% inhibition of Candida albicans and Fusarium lini, respectively.

Antiproliferative Activity and Characterization of Metabolites of Aspergillus nidulans: An Endophytic Fungus from Nyctanthes arbor-tristis Linn. Against Three Human Cancer Cell Lines.

BACKGROUND: Endophytic fungi are receiving attention as sources of structurally novel bioactive secondary metabolites towards drug discovery from natural products. This study reports the isolation and characterization of secondary metabolites from an endophytic fungus Aspergillus nidulans, associated with Nyctanthes arbor-tristis Linn., a plant which has a traditional use to cure many ailments including cancer. OBJECTIVE: The objective of this study was to evaluate the antiproliferative activity of the metabolites of A. nidulans from N. arbor-tristis on three human cancer cell lines, lung (NCI-H460), breast (MCF-7) and uterine cervix (HeLa), and carry out their characterization. METHODS: The extracts of the endophytic fungus cultured on potato dextrose agar were subjected to various chromatographic techniques. Structures of pure compounds were determined using spectroscopic techniques. The non-polar constituents were analyzed by GC-MS. Antiproliferative activity was determined by sulforhodamine B (SRB) assay. RESULTS: The extracts and fractions showed moderate to good growth inhibition of the aforementioned human cancer cell lines. The broth extract was most potent (IC50 = 10 ± 3.1 µg/mL and LC50= 95 ± 3.9) against HeLa whereas petroleum ether insoluble fraction of mycelium was most active against NCI-H460 and MCF-7 (IC50 = 10 ± 2.1 µg/mL and 18 ± 3.1 µg/mL respectively). GC-MS led to identify 12 compounds in mycelium and 19 compounds in broth. Four pure compounds were isolated and characterized one compound 5, 10-dihydrophenazine-1-carboxylic acid (1) from broth and three 1-hydroxy-3-methylxanthone (2), ergosterol (3) and sterigmatocystin (4) from mycelium. 1 has not been reported earlier as a plant/fungal metabolite while 2-4 are new from this source. Sterigmatocystin exhibited growth inhibitory effect (IC50 = 50 ± 2.5 µM/mL) against only MCF-7 cell line whereas other compounds had IC50 > 100. CONCLUSIONS: In this paper, the cytotoxicity of mycelium and broth constituents of endophytic fungus Aspergillus nidulans from Nyctanthes arbor-tristis is reported for the first time. The study shows that fungus Aspergillus nidulans from Nyctanthes arbor-tristis is capable of producing biologically active natural compounds and provides a scientific rationale for further chemical investigations of endophyte-producing natural products.