Bioactive compounds from mangrove derived rare actinobacterium Saccharomonospora oceani VJDS-3

A rare actinobacterium was isolated from Nizampatnam mangrove ecosystem of Andhra Pradesh, India, and was screened for its ability to produce bioactive compounds. The potential strain was identified as Saccharomonospora oceani VJDS-3 by polyphasic taxonomy. Purification of the biologically active compounds by column chromatography led to the isolation of three compounds, namely methoxy ethyl cinnamate (ethyl(E)-3-(4-methoxyphenyl)acrylate) (R1), 4-hydroxy methyl cinnamate (methyl(E)-3-(4-hydroxyphenyl)acrylate) (R2) and 4-methylbenzoic acid (R3). The structure of the compounds was elucidated on the basis of spectroscopic analysis including FTIR, EIMS, ¹HNMR and ¹³CNMR spectroscopies. The antimicrobial activity of the bioactive compounds produced by the strain was tested against a panel of bacteria and fungi, and expressed in terms of minimum inhibitory concentration. Compound (R1) exhibited higher antimicrobial potential (50 µg/ml) against Staphylococcus aureus, Bacillus megaterium and Candida albicans compared to R2 and R3. Antioxidant activity of compounds was determined by DPPH and ABTS radical scavenging activities. The results revealed that compound R3 effectively scavenged DPPH (73.08 ± 1.29) and ABTS (99.74 ± 0.00) radicals at a concentration of 25 and 50 µg/ml, respectively. Antidiabetic and anti-obesity activities were evaluated by inhibitory potential of compounds against alpha-glucosidase, alpha-amylase and pancreatic lipase by spectrophotometric assays. Compound R1 showed effective inhibition against alpha-glucosidase (66.8 ± 1.2) at 20 µg/ml while moderate to weak activities were found against alpha-amylase and pancreatic lipase. To the best of our knowledge, this is the first report on the isolation of supra said compounds from the genus Saccharomonospora.