Evaluation of the spectral characteristics, purity and antioxidant activity of C-phycocyanin from the cyanobacteria collected in Kaunas Lagoon (Lithuania)

Abstract

The physicochemical characteristics of phycocyanin extracted from cyanobacteria collected in Kaunas Lagoon were studied (spectrum characteristics, C-PC content in the dry mass and chemical purity). It was determined that the tested concentrations of C-PC in purified water should be in the range of 0.02–0.16% for measuring C-PC content in the dry mass and its spectrum characteristics. The two clear absorption maxima were detected in the spectrum of C-PC at the wavelengths of 277 and 619 nm. The content of C-PC in the dry powder form was in the range of 7.25% to 9.30% depending on its concentration in the solution and type of spectrophotometer. Furthermore, a purity factor of 1.5 was calculated, which indicated the food qualification of the obtained biomass of C-PC. Finally, the analytical procedure for studying the pro- and anti-oxidant activity of C-PC was developed and the antioxidant activity of C-PC was measured for the available markers. It was revealed that C-PC has dual properties (pro- and anti-oxidant ones) depending on its concentration, more exactly, its content in reaction mixtures with 2,2-diphenyl-1-picrylhydrazyl (DPPH). The following issues were resolved during the research: the concentration of ethanol in the DPPH solution was chosen in order to avoid precipitation of proteins in the reaction mixtures (50%); the ratio of the solution of C-PC to the DPPH solution was selected; the selected concentrations of the markers for the construction of their calibration curves were chosen for quercetin and for rutin. The antioxidant activity of the obtained C-PC sample was determined. Keywords: antioxidant activity, C-phycocyanin, cyanobacteria, DPPH, quercetin, rutin

Mentha piperita: Essential Oil and Extracts, Their Biological Activities, and Perspectives on the Development of New Medicinal and Cosmetic Products

“…However, it is not clear why the authors showed on the graphs the negative values of antioxidant activity in the DPPH test. As a rule, such values have compounds with prooxidant activity [97]. All the essential oils were cytotoxic for PMNs and PBMCs only at concentrations greater than 0.1 µg/mL in the MTT test.…”

“…Among the tests used to measure the antioxidant activity of M. piperita is the DPPH test (free radical scavenging activity) [1,12,18,20,63,81,88], β-carotene-linoleic acid assay, NO radical scavenging, reducing power [20], assessment of linoleic acid peroxidation through measurement of thiobarbituric acid reactive substances [1], etc. Antioxidants scavenge radicals through different mechanisms-hydrogen atom transfer or single electron transfer mechanism; or a combination of both mechanisms [16,17,97,98]. The ABTS and ORAC tests are based on the hydrogen atom transfer mechanism.…”

“…The DPPH and FRAP tests are based on the single electron transfer mechanism. However, it is very difficult to distinguish between the two mechanisms [17,[96][97][98]. In addition, the mechanism of the DPPH test can be based on the reaction of DPPH with ROSs and unsaturated hydrocarbons, joining hydrogen atoms from C-H bonds, for instance, from the C-H bonds of α-pinene [1,8,96].…”

“…In addition, the mechanism of the DPPH test can be based on the reaction of DPPH with ROSs and unsaturated hydrocarbons, joining hydrogen atoms from C-H bonds, for instance, from the C-H bonds of α-pinene [1,8,96]. DPPH test is sensitive and is widely used in food chemistry [1,2,12,17,19,31,86,[96][97][98].…”