Fermentation, purification and in-vitro evaluation of antimicrobial, antitumor and antioxidant compounds from a himalayan actinobacteria strain streptomyces sp. pu-ak14

This study reports the laboratory scale fermentation, compounds purification and bioactivity screening of the strain Streptomyces sp. PU-AK14 isolated from Himalayan mountains range, Pakistan, for its potential to produce antimicrobial, antioxidant and antitumor compounds. For this purpose, laboratory fermentation (20 L working volume) was performed followed by extraction of the compounds by XAD adsorbent gel using the solvents methanol and ethyl acetate. Further purification of the compounds was done by silica gel column chromatography, sephadex column and preparative TLC. A total of 18 partially purified compounds were retrieved from crude extract and were screened for biological activity. The crude extract was more active against gram negative bacteria with MIC of 0.1 mg/ml against Klebsiella pneumoniae and Escherichia coli. Eight of the partially purified compounds exhibited activity against MRSA whereas five fractions were active against gram negative bacteria. Seven partially purified fractions exhibited promising antioxidant activity with radical scavenging activity ranging from 78.2 to 42.34 percent. Cytotoxicity of partially purified compounds ranged from 75% to 100% larval mortality at 100mg/ml against Artemia salina and 50% to 52% cell mortality against HCT 116 colorectal cancer cell line at 100mg/ml. The best anti-tumor activity was exhibited by the fraction AK141111L. The study suggested that Streptomyces sp. PU-AK14 is a potential source of chemotherapeutically useful compounds.