title: Bio Prospecting of Marine-derived Streptomyces spectabilis VITJS10 and Exploring its Cytotoxicity Against Human Liver Cancer Cell Lines.
abstract: BACKGROUND
  Recently, numerous pathogens have developed resistance due to the indiscriminate use of commercial therapeutic drugs.
  
  
  OBJECTIVE
  The main aim of the study was to evaluate the bioactive potential of the Streptomyces spectabilis VITJS10 crude extract.
  
  
  METHODS
  The S. spectabilis VITJS10 ethyl acetate extract was tested for antibacterial, antioxidant, and cytotoxic properties. Genotypic characterization was done using 16S r-DNA partial gene amplification and sequencing. The authenticity of the crude chemical constitutes were determined by gas chromatography-mass spectrometry (GC-MS).
  
  
  RESULTS
  The antibacterial potential revealed the effective activity against Shigellaflexneri (MTCC No: 1457) (22 mm), Salmonella typhi (MTCC No: 1167) (23 mm), Escherichia coli (MTCC No: 1588) (22 mm), Pseudomonas aeruginosa (MTCC No: 4676) (22 mm) at 20 mg/mL concentration. Scavenging ability of the extract was determined using 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay revealing its 95% inhibition at 5 mg/mL concentration. Hepatocellular cancer cells (HepG2) cell line was used to evaluate the cytotoxicity by 3-(4, 5-dimethyl thiazol-2yl)-2, 5-diphenyl tetrazolium bromide assay. The extract showed maximum inhibition at IC50 of 250 μg/mL with 53.6% cell viability. The highest 16S rRNA gene sequence homogeneity was observed 99% similar with the novel strain S. spectabilis S3-1. The chemical components of the crude extract of VITJS10 were detected with 37 chemical constituents. However three major compounds were identified, namely Sulfurous acid, 2-ethylhexyl tridecyl ester, Phenol, 2,4-bis (1,1-dimethylethyl), and Trans-2-methyl-4-n-pentylthiane, S, S-Dioxide.
  
  
  CONCLUSIONS
  Hence the present study justifies the overwhelming circumstantial evidence as the most bioactive metabolites from the marine origin, which has potential utilization in pharmaceutical industry.
  
  
  CONCLUSIONS
  The aim of this study was to explore the bioactive potential of marine Streptomyces sp. isolated from marine soil and understand the bioactive properties of the crude extracts. It is clearly evident from the study that the bioactive metabolites produced by Streptomyces sp. exhibited good antibacterial, antioxidant and anticancer activity. Our results indicated that Starch casein medium was the good base for bioactive metabolite production. The taxonomic position of Streptomyces sp. isolated revealed unique pattern of phenotypic properties that distinguished it from representatives. The molecular characterization results provided valuable data for establishing the internal taxonomic structure of the genus. Hence high mortality rates, serious side effects, deficiencies of the available chemotherapeutics, and high costs during treatment clearly underscore the need to develop new anticancer agents, With the above significant features the strain could be recommended for its use in medicinal and agricultural sectors, an extensive knowledge on the behavior of natural compounds can be gained for the benefit of health.
authors.affiliation: Industrial Biotechnology Division, School of Biosciences and Technology, VIT University, Vellore, Tamil Nadu, India.
authors.forename: Jemimah Naine
authors.initials: JN
authors.lastname: Selvakumar
authors.affiliation: Industrial Biotechnology Division, School of Biosciences and Technology, VIT University, Vellore, Tamil Nadu, India.
authors.forename: Subathra Devi
authors.initials: SD
authors.lastname: Chandrasekaran
authors.affiliation: Industrial Biotechnology Division, School of Biosciences and Technology, VIT University, Vellore, Tamil Nadu, India.
authors.forename: Mohanasrinivasan
authors.initials: M
authors.lastname: Vaithilingam
keywords: Bioactivity; MARINE actinomycetes; Streptomyces spectabilis; VITJS10; cytotoxicity; secondary metabolites