Anti-Cryptococcus Phenalenones and Cyclic Tetrapeptides from Auxarthron pseudauxarthron

  • J Nat Prod. 2017 Jul 28;80(7):2101-2109. doi: 10.1021/acs.jnatprod.7b00341.
Yan Li  1 ,  Qun Yue  1 ,  Dinith R Jayanetti  2 ,  Dale C Swenson  2 ,  Geoffrey A Bartholomeusz  3 ,  Zhiqiang An  1 ,  James B Gloer  2 ,  Gerald F Bills  1
Affiliations
  • 1. Texas Therapeutic Institute, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston , Houston, Texas 77054, United States.
  • 2. Department of Chemistry, University of Iowa , Iowa City, Iowa 52242, United States.
  • 3. Department of Experimental Therapeutics, Division of Cancer Medicine, The University of Texas MD Anderson Cancer Center , Houston, Texas 77054, United States.
PMID: 28657331 DOI: 10.1021/acs.jnatprod.7b00341
Abstract

Auxarthrones A-E (1-5), five new phenalenones, and two new naturally occurring cyclic tetrapeptides, auxarthrides A (7) and B (8), were obtained from three different solvent extracts of cultures of the coprophilous fungus Auxarthron pseudauxarthron. Auxarthrones C (3) and E (5) possess an unusual 7a,8-dihydrocyclopenta[a]phenalene-7,9-dione ring system that has not been previously observed in natural products. Formation of 1-5 was found to be dependent on the solvent used for culture extraction. The structures of these new compounds were elucidated primarily by analysis of NMR and MS data. Auxarthrone A (1) was obtained as a mixture of chromatographically inseparable racemic diastereomers (1a and 1b) that cocrystallized, enabling confirmation of their structures by X-ray crystallography. The absolute configurations of 7 and 8 were assigned by analysis of their acid hydrolysates using Marfey's method. Compound 1 displayed moderate Antifungal activity against Cryptococcus neoformans and Candida albicans, but did not affect human Cancer cell lines.