engleski

COMPARISON OF THE COMPOSITION OF FREE VOLATILE COMPOUNDS OF THE SPECIES Veronica chamaedrys L. ISOLATED BY HYDRODISTILLATION AND MICROWAVE EXTRACTION

Studied Veronica chamaedrys L. (germander speedwell, family Plantaginaceae) belongs to the European-Mediterranean hemicryptophytes.[1] The plant material was collected from Delnice (Croatia) in July 2021 and was air dried. Free volatile compounds (FVCs) were isolated using two techniques: hydrodistillation (Hy) in Clevenger apparatus and microwave extraction (Me) in Etos X. The lipophilic (essential oils) and water (hydrosols) fractions were collected separately in both apparatuses. The aim of this study was to investigate the similarities and differences in the composition of the free volatile compounds isolated by these two techniques. The composition of the isolated compounds was analysed by gas chromatography coupled with mass spectrometry.[2] The composition of the lipophilic fraction obtained by both isolation techniques was dominated by the oxygenated sesquiterpenes caryophyllene oxide (Hy 18.63% ; Me 24.36%), followed by viridiflorol (Hy 7.89% ; Me 8.19%). Also, caryophyllene oxide (Hy 20.65% ; ME 20.26%) and viridiflorol (Hy 9.35% ; Me 12.36%) are the most abundant compounds in the hydrosol fractions. In our previous study FVCs of the genus Veronica, caryophyllene oxide was the main constituent of the Croatian endemic species V. saturejoides Vis. ssp. saturejoides.[3] Most of the identified compounds in the oil fraction obtained by both techniques are similar, and the most significant differences in percentage identification are for the compound E- caryophyllene (Hy 12.93% ; Me 1.57%) and phytol (Hy 5.26% ; Me 11.96%). In the hydrosol fractions, there were significant differences in the percentage identification of α- muurolol (Hy 12.15% ; Me 5.53%) and bornyl acetate (Hy 3.27% ; Me 10.67%). Overall, the difference in the composition of the FVCs of the lipophilic and hydrosol phases is that of a monoterpene hydrocarbons compound group. This group was identified in the hydrosol fractions using both isolation techniques. The differences in the composition of these FVCs are primarily due to different conditions in the isolation techniques as well as the solubility of the compounds. The different isolation techniques identified different compounds and thus obtained a more complete composition of the special metabolites. The plant produces special metabolites in response to stressful environmental conditions[4] and people use this product in natural treatments. New methods of extraction of FVCs are being introduced as greener solutions that consume less energy in the extraction processes are needed for the future usage of these compounds. The evaluation of the differences between the compositions of FVCs coming from different extraction techniques are valuable for the estimation of the quality of the product at the end of the extraction process. It is possible that greener solution will not be better for the composition of extracted FVCs for some plants. The FVCs identified in the species V. chamaedrys are a contribution to the knowledge of metabolites important for adaptation to environmental conditions in the genus Veronica and for potential biological activity testing. P-180

Veronica chamaedrys ; volatile compounds ; hydrodistillation ; Clevenger apparatus ; Microwave extraction

nije evidentirano