- Frenolicins C-G, Pyranonaphthoquinones from streptomyces sp. RM-4-15
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Appalachian active coal fire sites were selected for the isolation of bacterial strains belonging to the class actinobacteria. A comparison of high-resolution electrospray ionization mass spectrometry (HRESIMS) and ultraviolet (UV) absorption profiles from isolate extracts to natural product databases suggested Streptomyces sp. RM-4-15 to produce unique metabolites. Four new pyranonaphthoquinones, frenolicins C-F (1-4), along with three known analogues, frenolicin (6), frenolicin B (7), and UCF76-A (8), were isolated from the fermentation of this strain. An additional new analogue, frenolicin G (5), along with two known compounds, deoxyfrenolicin (9) and UCF 13 (10), were isolated from the fermentation supplied with 18 mg/L of scandium chloride, the first example, to the best of our knowledge, wherein scandium chloride supplementation led to the confirmed production of new bacterial secondary metabolites. Structures 1-5 were elucidated on the basis of spectral analysis and chemical modification. While frenolicins are best known for their anticoccidial activity, the current study revealed compounds 6-9 to exhibit moderate cytotoxicity against the human lung carcinoma cell line (A549) and thereby extends the anticancer SAR for this privileged scaffold.
- Wang, Xiachang,Shaaban, Khaled A.,Elshahawi, Sherif I.,Ponomareva, Larissa V.,Sunkara, Manjula,Zhang, Yinan,Copley, Gregory C.,Hower, James C.,Morris, Andrew J.,Kharel, Madan K.,Thorson, Jon S.
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p. 1441 - 1447
(2013/09/23)
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- TOTAL SYNTHESIS OF (+-)-NANAOMYCIN A AND (+-)-FRENOLICIN
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Efficient synthesis of (+-)-nanaomycin A and (+-)-frenolicin from a versatile intermediate is described.
- Ichihara, Akitami,Ubukata, Makoto,Oikawa, Hideaki,Murakami, Kazuo,Sakamura, Sadao
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p. 4469 - 4472
(2007/10/02)
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