Separation, identification and quantification of carotenoids and chlorophylls in dietary supplements containing Chlorella vulgaris and Spirulina platensis using High Performance Thin Layer Chromatography.

In this study, 14 commercial products (dietary supplements) containing alga Chlorella vulgaris and cyanobacteria Spirulina platensis, originated from China and Japan, were analysed. UV-vis spectrophotometric method was applied for rapid determination of chlorophylls, carotenoids and pheophytins; as degradation products of chlorophylls. High Performance Thin-Layer Chromatography (HPTLC) was used for effective separation of these compounds, and also Atomic Absorption Spectrometry for determination of heavy metals as indicator of environmental pollution. Based on the results obtained from UV-vis spectrophotometric determination of photosynthetic pigments (chlorophylls and carotenoids), it was confirmed that Chlorella vulgaris contains more of all these pigments compared to the cyanobacteria Spirulina platensis. The fastest mobility compound identified in Chlorella vulgaris and Spirulina platensis using HPTLC method was ß-carotene. Spectral analysis and standard calibration curve method were used for identification and quantification of separated substances on Thin-Layer Chromatographic plate. Quantification of copper (Cu2+, at 324.7 nm) and zinc (Zn2+, at 213.9nm) was performed using Flame Atomic Absorption Spectrometry with air-acetylene flame atomization. Quantification of cadmium (Cd2+, at 228.8 nm), nickel (Ni2+, at 232.0nm) and lead (Pb2+, at 283.3nm) by Electrothermal Graphite Furnace Atomic Absorption Spectrometry; and quantification of mercury (Hg2+, at 254nm) by Cold Vapour Atomic Absorption Spectrometry.

Comparative study on toxicity of extracellularly biosynthesized and laboratory synthesized CdTe quantum dots.

Nanobiosynthesis belongs to the most recent methods for synthesis of nanoparticles. This type of synthesis provides many advantages including the uniformity in particle shape and size. The biosynthesis has also a significant advantage regarding chemical properties of the obtained particles. In this study, we characterized the basic properties and composition of quantum dots (QDs), obtained by the extracellular biosynthesis by Escherichia coli. Furthermore, the toxicity of the biosynthesized QDs was compared to QDs prepared by microwave synthesis. The obtained results revealed the presence of cyan CdTe QDs after removal of substantial amounts of organic compounds, which stabilized the nanoparticle surface. QDs toxicity was evaluated using three cell lines Human Foreskin Fibroblast (HFF), Human Prostate Cancer cells (PC-3) and Breast Cancer cells (MCF-7) and the MTT assay. The test revealed differences in the toxicity between variants of QDs, varying about 10% in the HFF and 30% in the MCF-7 cell lines. The toxicity of the biosynthesized QDs to the PC-3 cell lines was about 35% lower in comparison with the QDs prepared by microwave synthesis.