Allostreptopyrroles A-E, β-alkylpyrrole derivatives from an actinomycete Allostreptomyces sp. RD068384.

Abstract

Five new β-alkylpyrrole derivatives, allostreptopyrroles A-E (1-5), were isolated from the culture broth of Allostreptomyces RD068384. Their structures were elucidated by 1D and 2D NMR spectroscopic analyses, HRESIMS, and chemical derivatization. The absolute configurations of compounds 2 and 3 were predicted by comparison of experimental and calculated specific rotation data. Compounds 1-5 are the first examples of natural pyrroles substituted by formyl and carboxyl functionalities. Compounds 1, 4, and 5 showed cytotoxicity against Kasumi-1 human acute myeloblastic leukemia cells with IC₅₀ values of 103, 105, and 105 μM, respectively, which are less active than the anticancer agent cisplatin, with an IC₅₀ value of 70 μM.