Identification of a new strain of Actinomadura isolated from Saharan soil and partial characterization of its antifungal compounds

Abstract

One promising strain Actinomadura sp. AC170, isolated from Algerian Saharan soil, with strong antifungal activity against pathogenic and toxinogenic fungi, was selected for further studies. The 16S rRNA results showed a distinct phylogenetic lineage from the other species within the Actinomadura genus. The production of antibiotic substances was investigated using GYEA solid medium. The butanolic extract contained four bioactive spots detected on thin layer chromatography plates. Among these antibiotics, a complex called 170A, which showed the more interesting antifungal activity, was selected and purified by reverse-phase HPLC. This complex is composed of four compounds. Ultraviolet-visible, infrared, mass and H nuclear magnetic resonance spectroscopy studies showed that these molecules contain an aromatic ring substituted by aliphatic chains. These compounds differ from the known antibiotics produced by Actinomadura species.

Key words: Actinomadura, taxonomy, antifungal compounds, Saharan soil.