Citromycetins and bilains A-C: new aromatic polyketides and diketopiperazines from Australian marine-derived and terrestrial Penicillium spp.
Chemical analysis of an Australian marine-derived isolate of Penicillium bilaii, collected from the Huon estuary, Port Huon, Tasmania, yielded the known fungal aromatic polyketides citromycetin (1) and citromycin (2) together with two dihydro analogues, (-)-2,3-dihydrocitromycetin (3) and (-)-2,3-dihydrocitromycin (4). An Australian terrestrial isolate of Penicillium striatisporum collected near Shalvey, New South Wales, also yielded citromycetin (1), citromycin (2), and the new dihydro analogue (-)-2,3-dihydrocitromycetin (3), together with fulvic acid (5), anhydrofulvic acid (6), and a selection of new methoxylated analogues, 12-methoxycitromycetin (7), 12-methoxycitromycin (8), (-)-12-methoxy-2,3-dihydrocitromycetin (9), and 12-methoxyanhydrofulvic acid (10). P. bilaii also yielded the rare siderophore pistillarin (11), the known diketopiperazines cyclo-(L-Phe -L-Pro) (12), cyclo-(L-Pro-L-Tyr) (13), cyclo-(L-Pro-L-Val) (14), and cis-bis(methylthio)silvatin (15), and three new diketopiperazines, bilains A-C (16-18). The structures for the Penicillium metabolites 1- 18 were assigned by a combination of detailed spectroscopic analysis, including correlation with relevant literature data, chemical derivatization, degradation, and biosynthetic considerations. The citromycin polyketides 2 and 4 and the diketopiperazine 15 were weakly cytotoxic.
Capon
Robert J
RJ
Centre for Molecular Biodiversity, Institute for Molecular Bioscience, University of Queensland, St. Lucia, Queensland 4072, Australia. r.capon@imb.uq.edu.au
Stewart
Michael
M
Ratnayake
Ranjala
R
Lacey
Ernest
E
Gill
Jennifer H
JH
D000595:Amino Acid Sequence; D000818:Animals; D001315:Australia; D001412:Bacillus subtilis / Q000187:drug effects; D004354:Drug Screening Assays, Antitumor; D004926:Escherichia coli / Q000187:drug effects; D006189:Haemonchus / Q000187:drug effects; D018942:Macrolides / Q000737:chemistry* / Q000302:isolation & purification* / Q000494:pharmacology; D008386:Marine Biology; D008826:Microbial Sensitivity Tests; D003904:Mitosporic Fungi / Q000187:drug effects; D015394:Molecular Structure; D010407:Penicillium / Q000737:chemistry*; D010879:Piperazines / Q000737:chemistry* / Q000302:isolation & purification* / Q000494:pharmacology; D011753:Pyrones / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D013309:Streptothricins / Q000494:pharmacology; D013648:Tasmania
D018942:Macrolides; D010879:Piperazines; D011753:Pyrones; C000487:citromycin; D013309:Streptothricins; C013444:citromycetin