Terrecyclic acid A, a new antibiotic from Aspergillus terreus. II. Structure of terrecyclic acid A

Miniaturized Cultivation Profiling Returns Indolo-Sesquiterpene Michael Adducts from the Australian Soil-Derived Aspergillus terreus CMB-SWF012

An integrated program of chemical profiling (GNPS) coupled with an expanded format 24-well-plate miniaturized cultivation profiling (MATRIX) utilizing traditional as well as grain/pulse and cereal media permitted rapid prioritization of Aspergillus terreus CMB-SWF012 as a source of unprecedented natural products. Scaled-up cultivation on rice and PDA yielded the rare tripeptides asterripeptides A-C (1-3), new indolo-sesquiterpene Michael adducts terreusides A and B (4 and 5), and known precursors asterresin A (6) and (+)-giluterrin (7). Structures for 1-7 were assigned by detailed spectroscopic and chemical analysis and biosynthetic considerations.

Molecular Networking and Cultivation Profiling Reveals Diverse Natural Product Classes from an Australian Soil-Derived Fungus Aspergillus sp. CMB-MRF324

This study showcases the application of an integrated workflow of molecular networking chemical profiling (GNPS), together with miniaturized microbioreactor cultivation profiling (MATRIX) to successfully detect, dereplicate, prioritize, optimize the production, isolate, characterize, and identify a diverse selection of new chemically labile natural products from the Queensland sheep pasture soil-derived fungus Aspergillus sp. CMB-MRF324. More specifically, we report the new tryptamine enamino tripeptide aspergillamides E-F (7-8), dihydroquinoline-2-one aflaquinolones H-I (11-12), and prenylated phenylbutyrolactone aspulvinone Y (14), along with an array of known co-metabolites, including asterriquinones SU5228 (9) and CT5 (10), terrecyclic acid A (13), and aspulvinones N-CR (15), B (16), D (17), and H (18). Structure elucidation was achieved by a combination of detailed spectroscopic and chemical analysis, biosynthetic considerations, and in the case of 11, an X-ray crystallographic analysis.

Cytotoxic constituents of Aspergillus terreus from the rhizosphere of Opuntia versicolor of the Sonoran Desert

A novel cyclopentenedione, asterredione (1), two new terrecyclic acid A derivatives, (+)-5(6)-dihydro-6-methoxyterrecyclic acid A (2) and (+)-5(6)-dihydro-6-hydroxyterrecyclic acid A (3), and five known compounds, (+)-terrecyclic acid A (4), (-)-quadrone (5), betulinan A (6), asterriquinone D (7), and asterriquinone C-1 (8), were isolated from Aspergillus terreus occurring in the rhizosphere of Opuntia versicolor, using bioassay-guided fractionation. Acid-catalyzed reaction of 2 under mild conditions afforded 4, whereas under harsh conditions 2 yielded 5 and (-)-isoquadrone (9). Catalytic hydrogenation and methylation of 4 afforded 5(6)-dihydro-terrecyclic acid A (10) and (+)-terrecyclic acid A methyl ester (11), respectively. The structures of 1-11 were elucidated by spectroscopic methods. All compounds were evaluated for cytotoxicity in a panel of three sentinel cancer cell lines, NCI-H460 (non-small cell lung cancer), MCF-7 (breast cancer), and SF-268 (CNS glioma), and were found to be moderately active. Cell cycle analysis of 2, 4, and 5 using the NCI-H460 cell line indicated that 4 is capable of disrupting the cell cycle through an apparent arrest to progression at the G(1) and G(2)/M phases in this p53 competent cell line. A pathway for the biosynthetic origin of asterredione (1) from asterriquinone D (7) is proposed.

Molecular structure of terrecyclodiol: a derivative of the antifungal metabolite terrecyclic acid A from Aspergillus terreus

A strain of Aspergillus terreus, which was isolated from organic mulch and inhibited the growth of the plant pathogen Phytophthora cinnamomi, produces an antifungal metabolite when grown in liquid culture. This metabolite was isolated by bioassay-guided fractionation and identified as terrecyclic acid A (1). X-ray diffraction studies and spectroscopic details of the derived terrecyclodiol (2) are described.