European Journal of Biotechnology and Bioscience 29 European Journal of Biotechnology and Bioscience Online ISSN: 2321-9122, Impact Factor: RJIF 5.44 www.biosciencejournals.com Volume 4; Issue 12, December 2016; Page No. 29-44 Study of Auxin, cytokinin and gibberellin-like activity of heterocyclic compounds derivatives of pyrimidine, pyridine, pyrazole and isoflavones *1 Victoria Tsygankova, 2 Yaroslav Andrusevich, 3 Olexandra Shtompel, 4 Olexandr Myroljubov, 5 Artem Hurenko, 6 Roman Solomyanny, 7 Galyna Mrug, 8 Mykhaylo Frasinyuk, 9 Oleg Shablykin, 10 Volodymyr Brovarets 1-3, 5-10 Department for Chemistry of Bioactive Nitrogen-Containing Heterocyclic Compounds, Institute of Bioorganic Chemistry and Petrochemistry, National Academy of Sciences of Ukraine, 1, Murmanskaya str., Kyiv, Ukraine 4 Department of Phytohormonology, M.G. Kholodny Institute of Botany, National Academy of Sciences of Ukraine, 2, Tereshchenkivska St., Kyiv, Ukraine *Corresponding author ScD Victoria Tsygankova, E-Mail: vTsygankova@ukr.net Abstract The phytohormone-like activity of synthetic low molecular weight heterocyclic compounds derivatives of pyrimidine, pyridine, pyrazole, and isoflavones was studied. Testing of stimulating effect of synthetic heterocyclic compounds on seed germination and seedling growth of flax (Linum usitatissimum L.) of cultivar Ukrainian 3 showed expressive auxin-like activity of these compounds. The growth parameters of 15 th -day-old flax seedlings grown on the solution of heterocyclic compounds used at concentration 10 - 8 M/l of distilled water were higher or similar to growth parameters of flax seedlings grown on the water solution of auxins IAA and NAA used at the same concentration as compared to lower growth parameters of control flax seedlings grown on the distilled water (control). The specific bioassay on auxin-like activity showed high stimulating effect of heterocyclic compounds derivatives of pyrimidine, pyridine, pyrazole, and isoflavones used at concentration 10 -8 M/l of distilled water on rhizogenesis on the 14 th -day-old leaf petioles isolated from seedlings of haricot bean (Phaseolus vulgaris L.) of cultivar Belozernaya. The specific bioassay on cytokinin-like activity conducted on the 16 th -day-old cotyledons isolated from seeds of muscat pumpkin (Cucurbita moschata Duch. et Poir.) of cultivar Gilea, showed that heterocyclic compounds derivatives of pyrimidine, pyridine, pyrazole, and isoflavones used at concentration 10 -8 M/l of distilled water demonstrated high stimulating activity on growth of biomass of isolated cotyledons of pumpkin, which was similar or higher than the activity of cytokinin Kinetin. The specific bioassay on gibberellin-like activity conducted on the 3 rd - day-old seedlings of lettuce (Lactuca sativa L.) of cultivar Berlin testified that some heterocyclic compounds derivatives of pyrazole, isoflavones, and pyridine used at concentrations ranging from 10 -4 M to 10 -9 M/1 of distilled water revealed minor stimulating effect on elongation of hypocotyl of lettuce seedlings in relation to control, but their activity was significantly lower than activity of gibberellic acid GA3. This bioassay showed also that the some heterocyclic compounds derivatives of pyrazole and isoflavones used at concentration 10 -7 M/l of distilled water demonstrated nonspecific for this bioassay auxin-like activity, which manifested in stimulation of formation and growth of root system on the seedlings of lettuce. Obtained results confirmed specific auxin-like and cytokinin-like, and minor gibberellin-like effect of synthetic heterocyclic compounds on cell division, cell proliferation, cell elongation and cell differentiation that are the basic processes of plant growth and development. Keywords: pyrimidine, pyridine, pyrazole, isoflavones, IAA, NAA, Kinetin, GA3, Phaseolus vulgaris L., Linum usitatissimum L., Cucurbita moschata Duch. et Poir., Lactuca sativa L 1. Introduction The successful development of modern biotechnological industry is based on using of high-intensive technologies of plant growing with application of phytohormones, synthetic plant growth regulators, natural biostimulants, herbicides, fungicides, organic and inorganic fertilizers to protect plants from abiotic and biotic stress factors causing adverse effects on plant growth and yield [1-18] . During the last decades the five major classes of natural phytohormones such as auxins, cytokinins, gibberellins, abscisic acid and ethylene are widely used in the agricultural practice as plant growth regulators [2, 4, 5, 19-31] . The newly identified plant growth substances such as brassinosteroids, jasmonates and salicylic acid have already received hormonal status [2, 4, 5, 19, 31-35] . Beside phytohormones the nontraditional compounds of natural origin such as polyamines, oligosaccharins, sterols, systemin, turgorins are known to regulate plant growth and development, but their manufacture for practical purposes is not provided until now [19, 35-37] . Nowadays the various classes of synthetic analogues of plant hormones having phytohormone-like activity are widely used in agriculture practice as plant growth regulators, herbicides and means for plant protection against pests and pathogens [1, 3, 6, 7, 19, 20, 23-25, 38, 39] . The new promising approach is elaboration of new classes of plant growth substances having high physiological activity at low concentrations, broad specificity of action on the different agricultural crops and lack of toxic effect for environment, animal and human health. In recent years the considerable attention is focused on study of plant growth regulating activity of different classes of low-molecular weight heterocyclic compounds, some of them derivatives of pyridine, pyrimidine, pyrazole, triazine, oxazole, oxazole