Chrysomycins, Anti-Tuberculosis C-Glycoside Polyketides from sp. MS751.

A new dimeric C-glycoside polyketide chrysomycin F (), along with four new monomeric compounds, chrysomycins G (), H (), I (), J (), as well as three known analogues, chrysomycins A (), B (), and C (), were isolated and characterised from a strain of sp. obtained from a sediment sample collected from the South China Sea. Their structures were determined by detailed spectroscopic analysis. Chrysomycin F contains two diastereomers, whose structures were further elucidated by a biomimetic [2 + 2] photodimerisation of chrysomycin A. Chrysomycins B and C showed potent anti-tuberculosis activity against both wild-type and a number of clinically isolated MDR strains.