Myxochelin A, a new catechole siderophore, was isolated from the culture broth of the myxobacterium, Angiococcus disciformis strain An d30. As is the case with other iron-chelating compounds the production of myxochelin A could be markedly increased up to 44 mg/liter by fermentation at low iron concentrations. The new substance showed weak activity against some bacteria. Myxochelin A is an inhibitor of tumor cell invasion produced by the bacterium belonging to the genus Nonomuraea. In order to obtain more potent inhibitors, a series of myxochelin analogues [2 and (S)-3-17] were synthesized through the coupling of lysine or diaminoalkane derivatives and appropriately protected hydroxybenzoate, followed by modification of functional groups and deprotection. These compounds were evaluated for their inhibitory activity against invasion of murine colon 26-L5 carcinoma cells.
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