ABSTRACT
Inthomycins are polyketide antibiotics which contain a terminal carboxamide group and a triene chain. Inthomycin B (1) and its two new analogues 2 and 3 were isolated from the crude extract of Streptomyces pactum L8. Identification of the gene cluster for inthomycin biosynthesis as well as the N-labeled glycine incorporation into inthomycins are described. Combined with the gene deletion of the rare P450 domain in the NRPS module, a formation mechanism of carboxamide moiety in inthomycins was proposed via an oxidative release of the assembly chain assisted by the P450 domain.
ABSTRACT
Cangumycins A-F (1-6), six new angucyclinone analogues, together with two known ones (7 and 8), were isolated from the fermentation broth of a soil-derived Streptomyces sp. KIB-M10. Structures of these compounds were elucidated via a joint use of spectroscopic analyses and single-crystal X-ray diffractions. Among them, cangumycins E (5) and F (6) share a C-ring cleaved backbone, and cangumycins B (2) and E (5) exhibit potent immunosuppressive activity (IC 8.1 and 2.7 μmol·L, respectively) against human T cell proliferation at a non-cytotoxic concentration.
ABSTRACT
<p><b>OBJECTIVE</b>To study the chemical constituents in the total saponin from Trigonellf foenum-graecum.</p><p><b>METHOD</b>The compounds were isolated by column chromatography on macroporous resin and silica gel and elucidated by physical and chemical evidences and spectroscopic analysis.</p><p><b>RESULT</b>Two compounds were obtained and identifiedas methyl-protodioscin and methyl-protodeltonin.</p><p><b>CONCLUSION</b>Methyl-protodioscin and methyl-protodeltonin were isolated from this plant for the first time.</p>