Evaluation of antimicrobial and antiproliferative activities of actinobacteria isolated from the saline lagoons of northwest peru

The unexplored saline lagoons of the north of Peru harbor a rich microbiome, due to reported studies of different extreme environments around the world. In these regions, there are several ecosystems and microhabitats not yet explored, and little is known about the diversity of actinobacteria and other microorganisms. We suggest that the endemic bacteria present in this extreme environment could be source of active molecules with anticancer, antimicrobial, antiparasitic properties. Using phenotypic and genotypic characterization techniques including the 16S rRNA were identified into the genera Streptomyces 39 (78%), Pseudonocardia 3 (6%), Staphylococcus 4 (8%), Bacillus 2 (4%), and Pseudomonas 2 (4%). All isolated bacteria for the genotypic data were preliminarily identified. Actinobacteria strains were found dominantly in both sites (Lagoon1-3 = 16 isolates and lagoon 4 = 12 isolates). Phylogenetic analysis revealed that 28 isolates were exclusively affiliated to eleven different clusters of Actinobacteria of the major genus Streptomyces . Three Streptomyces sp. strains M-92, B-146, and B-81, were tested for antibacterial and antiproliferative activities. The results showed antiproliferative activities against three tumor cell lines, U251 glioma; MCF7 breast; NCI-H460 lung non-small type of cells, and the antibacterial activity to Staphylococcus aureus ATCC 6538, E. coli ATCC 10536, and Acinetobacter baumanni AC-972 which is resistant to multiple drugs. The promising results belong to Streptomyces sp. B-81 strain in the R2A medium using a doxorubicin with control positive, the best result was from the latter (TGI = 0,57 µg/mL) for glioma; NCI-H460 lung of type non-small cells (TGI = 0,61 µg/mL), and breast cancer (TGI =0,80 µg/mL), this strain was selected to be fractionated because it had better antiproliferative and antibacterial activity, and its fractions were evaluated concerning antiproliferative activity against nine types of tumor cells and one non-tumor. The methanolic fraction showed a better result in the antiproliferative activity and was able to inhibit U251 (glioma) (TGI = 38.3 µg/mL), OVCAR-03 (ovary) (TGI = 62.1 µg/mL), and K562 (leukemia) (TGI = 81.5 µg/mL). The methanol 50% - acetate 50% fraction (Fraction 4) inhibited U251 (glioma) (TGI = 73.5 µg/mL) and UACC-62 (melanoma) (TGI = 89.4 µg/mL). Moreover, the UHPLC-MS/MS data and molecular networking of Streptomyces sp . B-81 isolate extract revealed the production cholic acid, Lobophorin A, Lobophorin B, Lobophorin E, Lobophorin K and compound 6. Extremophilic environments such as the Mórrope and Bayovar Salt Flats are promising sources of new bacteria with promising pharmaceutical potential; These compounds could be useful to treat various infectious diseases or even some type of cancer. ### Competing Interest Statement The authors have declared no competing interest.