Characterization and Biological Activity of Daunomycinone Produced by Actinomyces Strain Isolated from Egyptian Soil

Abstract

The ongoing rise of microbial antibiotic resistance underscores the importance of discovering new antimicrobial agents. Thus, this research aims to isolate and identify an antimicrobial agent from Actinomyces species living in Egyptian soil and test for other biological activities. To address this objective, an Actinomyces isolate strain was obtained from Egyptian soil and subsequently identified using 16S rRNA sequence analysis method. We used a bioassay-directed fractionation to guide the isolation of a bioactive compound from the fermentation broth of the isolated active Actinomyces strain using the well-diffusion method. The bioactive compound was characterized, and tested on human tumor cell line viability using MTT assay, and on Raw 264.7 macrophage cells nitrite production ability using Griess reagent. Our results showed the isolation and identification of Actinomyces vulturis FHM51 strain from the Egyptian soil that possessed an antimicrobial activity. Furthermore, daunomycinone was isolated from the fermentation medium that showed promising antimicrobial activity with MIC for example 100 μg/mL for Pseudomonas aeruginosa, 120 μg/mL for
Salmonella Typhimurium, and for multidrug-resistant pathogens: 2000 μg/mL for Escherichia coli 797 and Candida albicans 210, and 2500 μg/mL for methicillin-resistant Staphylococcus aureus. In addition, daunomycinone showed a selective cytotoxicity against human leukemia HL-60 cells when compared to the non-tumor fibroblasts BJ cells with selectivity index of 2.78. Finally, daunomycinone
showed a promising anti-inflammatory effect by inhibiting lipopolysaccharide-mediated nitrite production of Raw 264.7 macrophage cells. Collectively, daunomycinone, isolated from Actinomyces vulturis strain FHM51, possesses promising antimicrobial, cytotoxic and anti-inflammatory properties.