Hinduchelins A-D, Noncytotoxic Catechol Derivatives from Streptoalloteichus hindustanus

Four new catechol derivatives, hinduchelins A–D (1–4), composed of 2,3- dihydroxybenzoic acid, threonine, and decarboxylated phenylalanine, were isolated from Streptoalloteichus hindustanus. Their structures and absolute configurations were elucidated by interpretation of NMR and HRMS data and quantum chemical ECD calculations. The iron-binding properties of the compounds were evaluated by a pyoverdine production assay in Pseudomonas aeruginosa, and compound 4 showed moderate ability to induce pyoverdine production at 50 μM. None of the compounds were cytotoxic toward HL-20, A549, SMMC-7721, MCF-7, and SW-480 tumor cell lines.