Violapyrones A–G, α-Pyrone Derivatives from Streptomyces violascens Isolated from Hylobates hoolock Feces

Abstract

Seven new 3,4,6-trisubstituted α-pyrone derivatives, violapyrones A-G (1-7), were isolated from Streptomyces violascens obtained from Hylobates hoolock feces. Their structures were elucidated on the basis of detailed spectroscopic analysis. The antimicrobial activities of 1-7 were evaluated against Gram-positive and Gram-negative bacteria and against fungi. Compounds 1-3 showed moderate antibacterial activities against Bacillus subtilis and Staphylococcus aureus with MIC values of 4-32 μg/mL.

α-Pyrone Derivatives from a Streptomyces Strain Resensitize Tamoxifen Resistance in Breast Cancer Cells

“…KIB-H0495 was centrifuged to obtain supernatant and a mycelial cake, which were extracted with ethyl acetate and acetone, respectively. Both extracts were combined and then applied on repeated silica gel chromatograph column (CC), MCI gel CHP20P column, and semipreparative HPLC to yield four α -pyrone derivatives violapyrones B ( 1 ) [19], J ( 2 ), K ( 3 ), and I ( 4 ) [20] (Fig. 1).…”

“…KIB-H0495 significantly inhibited resistant strains MCF-7/TamR. Further fermentation and isolation towards this strain led to the identification of four α -pyrone derivatives including two new ones, violapyrones J ( 2 ) and K ( 3 ), and two known analogues, violapyrones B ( 1 ) [19] and I ( 4 ) [20] (Fig. 1).…”

New α-pyrone and phthalide from the Xylariaceae fungus

“…a-Pyrones are common metabolites of the fungi showing a wide range of biological activities, such as antibacterial [14] and cytotoxic activities [15]. In recent years, a series of a-pyrones have been reported from the fungi, including Paecilomyces sp.…”

“…[18], and Streptomyces sp. [14]. Phthalides are abound in the fungi and plants, such as Cladosporium sp.…”

Selective pyrone functionalization: reductive alkylation of triacetic acid lactone

“…Pyrone 3 was isolated from Streptomyces violascens obtained from Hylobates hoolock feces and showed moderate antibacterial activities against Bacillus subtilis and Staphylococcus aureus with MIC values of 4-32 lg/mL. 3 Compound 4 is involved in signaling at nanomolar concentrations in certain bacteria. 4 Although many synthetic analogues of 1 have been prepared by acylation/cyclization protocols, the direct alkylation of 1 at C-3 is rare.…”