Sarubicinols A–C, Cytotoxic Benzoxazoles from a Streptomyces

Abstract

A chemical investigation of Streptomyces sp. Hu186 afforded two known quinone antibiotics, sarubicin A (1) and sarubicin B (2), together with three unusual variants, sarubicinols A−C (3−5), and two new 1,4naphthoquinone metabolites, sarubicin B 1 (6) and sarubicin B 2 (7). Compounds 3−5 possess a rare 2-oxabicyclo [2.2.2] substructure and a benzoxazole ring system. Their structures were elucidated using 1D and 2D nuclear magnetic resonance and high-resolution electrospray ionization mass spectrometry data. The absolute configurations of the side-chain moieties in 4 and 5 were solved by electronic circular dichroism calculations. Compounds 1−7 showed moderate cytotoxic activity against four tumor cell lines.

Anti-Inflammatory Polyketides from an Alga-Derived Fungus Aspergillus ochraceopetaliformis SCSIO 41020

“…The relative configurations of C-4/C-5 and C-8/C-9 were analyzed by proton–proton spin-coupling constant analysis. The large coupling constants, 3 J H4-H5 (7.0 Hz) and 3 J H8-H9 (8.5 Hz), indicated the threo configurations of C-4/C-5 and C-8/C-9 [ 17 , 18 ]. Furthermore, the absolute configuration of the linear polyketide ( 1 ) was alternatively determined by comparison of the experimental ECD curves with that of compound 2 ( Figure 2 c).…”

Natural products as anthelmintics: safeguarding animal health

“…190,191 Signicantly, oral administration in a T. colubriformis gerbil infection model reduced faecal egg counts, 4.32 (EC 100 0.25 mg kg −1 ), 4.33 (EC 98 0.25 mg kg −1 ), 4.34 and 4.35 (EC 99 1.0 mg kg −1 ), while a mixed roundworm (Haemonchus, Teladorsagia, Trichostrongylus, Cooperia, Nematodirus and Chabertia) sheep infection model conrmed a potent decrease in worm burden for 4.32 (EC 100 all species 0.4 mg kg −1 ) and 4.33 (EC 100 most species 0.8 mg kg −1 ). 190 195,196 A follow up study of S. microavus neau3 in 2011 returned the C. elegans active aromatic nemadectin analogue 4.54 (IC 50 17 mg mL −1 ). 197 Likewise, a 2013 study of a mutant strain (Y-3) of S. microavus neau3 returned 4.55 and 4.56.…”