10023-07-1Relevant articles and documents
Frenolicins C-G, Pyranonaphthoquinones from streptomyces sp. RM-4-15
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.
, p. 1441 - 1447 (2013/09/23)
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.