Induction of A549 Nonsmall-Cell Lung Cancer Cells Proliferation by Photoreleased Nicotine.

Caged compounds comprise the group of artificially synthesized, light-sensitive molecules that enable in situ derivation of biologically active constituents capable of affecting cells, tissues and/or biological processes upon exposure to light. Ruthenium-bispyridine (RuBi) complexes are photolyzed by biologically harmless visible light. In the present study, we show that RuBi-caged nicotine can be used as a source of free nicotine to induce proliferation of A549 nonsmall-cell lung cancer (NSCLC) cells by acting on nicotinic acetylcholine receptors expressed in these cells. RuBi-nicotine was photolyzed using LED light source with the spectrum matching RuBi-absorption. Photorelease of free nicotine ([Nic]p/r ) was quantified by high-performance liquid chromatography (HPLC). 5-s-long light exposure of 10 µm of RuBi-nicotine generated 2 µm [Nic]p/r which enhanced A549 cell proliferation similarly to the 2 µm of plain nicotine during 72 h of cell culturing. Both RuBi-nicotine per se and its photolysis byproduct exerted no effect on A549 cells. We conclude that RuBi-nicotine can be a good source of free nicotine for inducing short- and long-term biological effects. Photolysis of RuBi-nicotine is quite effective, and can produce biologically relevant concentrations of nicotine at acceptable concentrations of the source material with the use of simple, inexpensive, and easily accessible light sources.

Comparative Analysis of Cytokinins in Mycelial Biomass of Medicinal Mushrooms.

Mushrooms are known to produce phytohormones, in particular cytokinins. Here we studied in vitro production of cytokinins in medicinal mushrooms. Cytokinins were identified and quantified in mycelial biomass of 13 species by using high-performance liquid chromatography-mass spectrometry. Trans-zeatin, zeatin riboside, zeatin-O-glucoside, isopentenyladenosine, and isopentenyladenine were found but only 1 species (Ganoderma lucidum) contained all these forms. Zeatin-type cytokinins predominated. Composition of the cytokinin pool was unique in each species. The largest total amount of cytokinins was detected in Morchella esculenta strain 1755 and the smallest amount, in Flammulina velutipes strain 1878. The productivity of cytokinin biosynthesis in mycelial biomass of mushrooms was the lowest in mycelial biomass of Sparassis crispa strain 314 and highest in Pleurotus ostreatus strain 551. F. velutipes strain 1878 and Cyclocybe aegerita strain 960 mycelial biomass showed the most productive zeatin riboside biosynthesis. We emphasize the need to take into account the biological activity of cytokinins, on the basis of the mycelial biomass of medicinal mushrooms, in the development of drugs or dietary supplements. Macromycetes with high rates of cytokinin biosynthesis are considered to be prospective producers of pharmacologically active compounds.