138
S. Sengupta J. Bhowal
R 1 and P. aeruginosa U 3 which possessed 97% nucleotide sequence identity to those
of P. aeruginosa FPVC 14 and 94% similarity with those of P. aeruginosa 13.A,
respectively.
3.3 Production and Extraction of Extracellular Microbial
Pigment
Blue-colored microbial pigment was obtained after solvent (chloroform) extraction.
3.4 Antioxidant Assays
3.4.1 DPPH (1,1-Diphenyl-2-Picrylhydrazyl) Free Radical Scavenging
Activity
DPPH radical scavenging activity (%) was found to be 47.79 ± 0.05% and the
IC 50 value was evaluated at 4.75 µg/ml. Ascorbic acid was used as standard. These
results are significantly higher than in the study carried out by Dahah et al. (2016)
who observed the IC 50 value of pyocyaninat 3.15 µg/ml.
3.4.2 Free Radical Scavenging Activity (%) Against ABTS+
The ABTS+ radical scavenging activity was significantly (p ≤ 0.05) high, i.e., 43.63
± 0.3% at 3.50 µg/ml concentration of pyocyanin which was comparable to that of
standard, ascorbic acid. Pawar et al. (2015) reported that the bacterial pigment (PIGB
77) exhibited 38.9 ± 1.98% radical scavenging activity.
3.4.3 Ferric-Reducing Antioxidant Power (FRAP) Assay
FRAP value was recorded as 8.99 ± 0.23 for 1 mg/ml sample concentration. Ferric
chloride was used as the standard. This was significantly higher than the results of
Pawar et al. (2015) where it was reported that the FRAP value was 7.97 ± 0.12 for
1 mg/ml concentration of pigment produced by Pseudomonas argentinensis (PIGB
46) and 5.90 ± 0.13 for 1 mg/ml in case of the pigment produced by Pseudomonas
koreensis (PIGB 77).
S. Sengupta J. Bhowal
R 1 and P. aeruginosa U 3 which possessed 97% nucleotide sequence identity to those
of P. aeruginosa FPVC 14 and 94% similarity with those of P. aeruginosa 13.A,
respectively.
3.3 Production and Extraction of Extracellular Microbial
Pigment
Blue-colored microbial pigment was obtained after solvent (chloroform) extraction.
3.4 Antioxidant Assays
3.4.1 DPPH (1,1-Diphenyl-2-Picrylhydrazyl) Free Radical Scavenging
Activity
DPPH radical scavenging activity (%) was found to be 47.79 ± 0.05% and the
IC 50 value was evaluated at 4.75 µg/ml. Ascorbic acid was used as standard. These
results are significantly higher than in the study carried out by Dahah et al. (2016)
who observed the IC 50 value of pyocyaninat 3.15 µg/ml.
3.4.2 Free Radical Scavenging Activity (%) Against ABTS+
The ABTS+ radical scavenging activity was significantly (p ≤ 0.05) high, i.e., 43.63
± 0.3% at 3.50 µg/ml concentration of pyocyanin which was comparable to that of
standard, ascorbic acid. Pawar et al. (2015) reported that the bacterial pigment (PIGB
77) exhibited 38.9 ± 1.98% radical scavenging activity.
3.4.3 Ferric-Reducing Antioxidant Power (FRAP) Assay
FRAP value was recorded as 8.99 ± 0.23 for 1 mg/ml sample concentration. Ferric
chloride was used as the standard. This was significantly higher than the results of
Pawar et al. (2015) where it was reported that the FRAP value was 7.97 ± 0.12 for
1 mg/ml concentration of pigment produced by Pseudomonas argentinensis (PIGB
46) and 5.90 ± 0.13 for 1 mg/ml in case of the pigment produced by Pseudomonas
koreensis (PIGB 77).