[Identification of 3-demethylchuangxinmycin from Actinoplanes tsinanensis CPCC 200056].

Chuangxinmycin (CM) from Actinoplanes tsinanensis was an antibiotic discovered by Chinese scientists about 40 years ago. It contains a new heterocyclic system of indole fused with dihydrothiopyran, whose biosynthetic mechanism remains unclear. CM is used as an oral medicine in the treatment of bacterial infections in China. The simple structure makes CM as an attractive candidate of structure modification for improvement of antibacterial activity. Recently, we analyzed the secondary metabolites of Actinoplanes tsinanensis CPCC 200056, a CM producing strain, as a natural CM analogue. We discovered the first natural CM analogue 3-demethylchuangxinmycin (DCM) as a new natural product. Compared to CM, DCM exhibited a much weaker activity in the inhibition of the bacterial strains tested. The finding provides valuable information for the structure-activity relationship in the biosynthesis of CM.

Aromatic acid derivatives from the lateral roots of Aconitum carmichaelii.

Seven new aromatic acid derivatives (1-7), together with five known analogs, were isolated from the lateral roots of Aconitum carmichaelii. Structures of the new compounds were determined by spectroscopic and chemical methods as 4-methyl ( - )-(R)-hydroxyeucomate (1), 4-butyl ( - )-(R)-hydroxyeucomate (2), 4-butyl-1-methyl (+)-(R)-2-O-(4'-hydroxy-3'-methoxybenzoyl)malate (3), 1-butyl-4-methyl (+)-(R)-2-O-(4'-hydroxy-3'-methoxybenzoyl)malate (4), dimethyl (+)-(R)-2-O-(4'-hydroxy-3'-methoxybenzoyl)malate (5), dimethyl (+)-(R)-2-O-(4'-hydroxybenzoyl)malate (6), and methyl ( ± )-3-(4'-hydroxy-3'-methoxyphenyl)-3-sulfopropionate (7), respectively. Compounds 1 and 2 are 2-benzylmalates (eucomate derivatives), 3-6 belong to 2-O-benzoylmalates, and 7 is a rare phenylpropionate containing a sulfonic acid group. The absolute configurations of eucomate derivatives were confirmed by X-ray crystallographic analysis of 4-methyl eucomate (11).