Isolation of Secondary Metabolites from Marine Streptomyces sparsus ASD203 and Evaluation its Bioactivity

The marine-derived actinomycetes streptomyces was isolated with 7 bacterial isolates from sponge Crella cyathophora and selected based on antimicrobial activity. Selected bacterial strain was identified morphologically and genetically by sequencing of its 16s rRNA gene as Streptomyces sparsus. Five compounds from ethyl acetate extract of Streptomyces sparsus were separated and purified using column chromatography. Identification of their structures was done using different spectroscopic analyses and by matching the data with literature reported. This is the first report of these isolated compounds from Streptomyces sparsus species: stearic acid, 9-heptadecenoic acid, palmitoleic acid, cedarmycin A, and phytol acetate. Antibacterial activity and minimal inhibitory concentration of compounds were measured via MTP assay against two Gram-positive and four Gram-negative bacteria isolates. Results revealed that cedarmycin A is the most potent one against all test microorganisms. Antioxidant capacity of compounds and extract were examined using DPPH radical scavenging capacity assay, cedarmycin A showed maximum activity of 71.54%. Also, biofilm inhibition activity of compounds was measured toward four pathogenic bacteria using MTP assay, showing biofilm inhibition activity. Hence, Streptomyces sparsus could be good source for secondary metabolites, and ethyl acetate extract may have these biological activities due to the presence of diverse metabolites.

Automated summary

In this study, the marine-derived actinomycetes Streptomyces sparsus was isolated from sponge Crella cyathophora. Five compounds were identified from the ethyl acetate extract of Streptomyces sparsus and evaluated for their antimicrobial, antioxidant, and biofilm inhibition activities.