Жирнокислотний клад сировини Zinnia elegans

Abstract

Introduction. Zinnia elegans Jacq. is a herbaceous plant of the Asteraceae family, which originates from Mexico and Central America. This plant is grown in many countries of the world as an ornamental plant. Currently, researches are being carried out on Zinnia elegans regarding the study of its chemical composition and pharmacological activity. In the course of the conducted experiments, antioxidant and hepatoprotective activity was established for the raw materials of this plant. As for the chemical composition, modern research is mainly devoted to phenolic compounds. There is also information on the study of other species of plants of the genus Zinnia, in particular Zinnia pauciflora. The presence of essential oil, flavonoids, in particular anthocyanins, was established in the raw materials of this plant, and fatty acids were also studied. The fatty acid composition was studied in the seeds of Zinnia pauciflora, as a result, the predominance of such acids as linoleic (34.98%), palmitic (17.27%) and oleic (13.33%) was established. The modern scientific papers describe information on the pharmacological activity of plant extracts containing fatty acids, namely anti-inflammatory, antimicrobial, antioxidant. Since fatty acids can determine the pharmacological effect, their study in plant raw materials is definitely necessary. The aim of the work was to study the fatty acid composition of the raw materials of Zinnia elegans. Materials and methods. For the experiment, we used herb, leaves, flowers, stems and roots of Zinnia elegans, which were harvested in the flowering phase in Ukraine (Kharkiv region) in August 2021. The raw material is a mixture of such varieties as Karusel and Rozhevyi briliant. Fatty acids were revealed in the form of their methyl esters. Fatty acid methyl esters were studied at Selmichrome-1 gas chromatograph with a flame ionization detector. Stainless steel gas chromatography column, 2,5 meters long and 4 mm internal diameter, was filled with stationary phase – inerton treated with 10% diethyleneglycol succinate (DEGS). Chromatograph operation parameters: column thermostat temperature – 180°С; vaporizer temperature – 230°С; detector temperature – 220°С; carrier gas (nitrogen) flowrate – 30 cm³/min; sample 2 mm³ acids methyl esters solution in hexane. Fatty acid methyl esters were indentified by retention time of fatty acid methyl esters peak standard samples as compared to standard mixture. Reference samples were Merck standards of saturated and unsaturated fatty acid methyl esters. Composition of methyl esters was calculated by internal normalzation method. Fatty acid methyl esters were obtained by modified Peisker method to ensure total methylation of fatty acids. For methylation a 100:100:1 mixture of chloroform with methanol and sulfuric acid was used. 30-50 µl lipophilic fraction was measured to glass ampoules, 2,5 ml methylating mix added and ampoules were sealed. Then they were introduced to thermostat at 105°С for 3 hours. After methylation the ampoules were opened, their contents transferred to a beaker, zink sulfate added on lancet tip, 2 ml purified water and 2 ml hexane  were poured in for extraction of methyl esters. After thorough shaking and settling the hexane extract was filtered off and used for chromatographic analysis. Research results. As a result of the conducted research, the presence of 13 fatty acids was established in herb, leaves and stems of Zinnia elegans, and 14 in the flowers and roots. Unsaturated fatty acids predominated in all studied samples. The highest content of them was observed in flowers of Zinnia elegans (71.94%), the lowest amount was found in the leaves (56.50%). Among the unsaturated acids, linoleic acid dominated in all raw material samples. Regarding saturated acids, palmitic acid prevailed in all studied raw materials. Conclusions. So, the conducted research made it possible to study the fatty acid composition of raw materials, namely herb, leaves, flowers, stems, and roots of Zinnia elegans. Dominance was established in all studied objects by the amount of unsaturated fatty acids. The obtained data can be used in the development of the technology of medicinal products based on Zinnia elegans raw materials.

Keywords: Zinnia elegans, fatty acids, gas chromatography