title: Pyramidamycins A-D and 3-hydroxyquinoline-2-carboxamide; cytotoxic benzamides from Streptomyces sp. DGC1.
abstract: Four new benzamides, pyramidamycins A-D (2-5) along with the new natural 3-hydroxyquinoline-2-carboxamide (6) were isolated from the crude extract of Streptomyces sp. DGC1. Additionally, five other known compounds, namely 2-aminobenzamide (anthranilamide) (1), 4',7-dihydroxyisoflavanone (7), 2'-deoxy-thymidine, 2'-deoxy-uridine and adenosine were also isolated and identified. The structures of the new compounds 2-6 were elucidated by 1D and 2D NMR studies along with HR MS analyses. The isolated compounds 1-6 contained the same amide side chain. The isolated compounds 1-7 were biologically evaluated in comparison with landomycin A against a prostate cancer cell line (PC3) and non-small cell lung cancer cell line (H460) for 48 h and against several bacterial strains. Pyramidamycin C (4) was the most active compound against both PC3 and H460 cell lines (GI(50)=2.473 and 7.339 μM, respectively). Benzamides (1-3) demonstrated inhibitory activity against Kocuria rosea B-1106 (a diameter halo of 13±2 mm for 1; 10±2 mm for 2 and 3). Compound 6 was slightly active against both Escherichia coli DH5α and Micrococcus luteus NRRL B-2618 (diameter halos 8±2 and 9±2 mm, respectively). Taxonomically, the amplified 500-bp 16 S rRNA fragment of the Streptomyces sp. DGC1 had 99% identity (BLAST search) to the 16S rRNA gene of Streptomyces atrovirens strain NRRL B-16357.
authors.affiliation: Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY 40536-0596, USA.
authors.forename: Khaled A
authors.initials: KA
authors.lastname: Shaaban
authors.forename: Micah D
authors.initials: MD
authors.lastname: Shepherd
authors.forename: Tamer A
authors.initials: TA
authors.lastname: Ahmed
authors.forename: S Eric
authors.initials: SE
authors.lastname: Nybo
authors.forename: Markos
authors.initials: M
authors.lastname: Leggas
authors.forename: Jürgen
authors.initials: J
authors.lastname: Rohr
mesh_terms: D000617:Aminoglycosides / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D000970:Antineoplastic Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects; D001549:Benzamides / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D002289:Carcinoma, Non-Small-Cell Lung / Q000188:drug therapy / Q000473:pathology; D045744:Cell Line, Tumor; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy / Q000473:pathology; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D013058:Mass Spectrometry; D011471:Prostatic Neoplasms / Q000188:drug therapy / Q000473:pathology; D011804:Quinolines / Q000302:isolation & purification / Q000494:pharmacology*; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S; D013302:Streptomyces / Q000235:genetics / Q000378:metabolism*
chemical_list: C578276:3-hydroxyquinoline-2-carboxamide; D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D000970:Antineoplastic Agents; D001549:Benzamides; D011804:Quinolines; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; C064648:landomycin A