Evaluation of Antiphytoviral and Antibacterial Activity of Essential Oil and Hydrosol Extracts from Five Veronica Species

Abstract

Agricultural production without pollution is possible using bioactive plant compounds, which include essential oils as important substances of plant origin. The aim of this study was to evaluate the antiphytoviral and antibacterial potentials of lipid (essential oil, EO) and water (hydrosol, HY) extracts from five Veronica species (Plantaginaceae) obtained by Clevenger hydrodistillation (HD) and microwave-assisted extraction (MAE), with analysis by gas chromatography coupled with mass spectrometry. The antiphytoviral activities of both extracts were tested on local host plants infected with tobacco mosaic virus (TMV). The antibacterial potential was tested against ten strains of opportunistic pathogens using the broth microdilution test. Species V. chamaedrys EO-MAE extract, V. arvensis EO from both extractions and V. montana, V. serpyllifolia, and V. persica EO-HD extracts were more effective in inhibiting TMV infection. Furthermore, HY- HD extracts of V. arvensis, V. chamaedrys and V. persica showed significant antiphytoviral activity. HY fractions had no effect on bacterial growth, regardless of the Veronica species tested, likely due to the fact that the maximum concentrations of the HY fractions tested in this study were low (1.83 and 2.91 mg/mL). EOs showed significant antibacterial activity independent of the extraction method. Notably, V. chamaedrys EO-MAE fraction, showed significantly better activity against Listeria monocytogenes and Enterococcus faecalis. Also, the EO-HD fraction of V. arvensis showed slightly better antibacterial activity. By combining extracts and using different extraction methods, valuable bioproducts can be obtained from the investigated Veronica species for safe use in agricultural production and food conservation.

Significant Benefits of Environmentally Friendly Hydrosols from Tropaeolum majus L. Seeds with Multiple Biological Activities

“…The HY isolated using MAE had higher amount of BITC than the HY isolated using the MHG extraction technique, where BCN dominates; according to previous research, ITCs have been proven to be the most biologically active degrading components of glucosinolates [2,42]. Although previous research on HYs has been insignificant in terms of antibacterial activity, according to the research of Nazlić et al, essential oils have a stronger effect compared to HYs, which is consistent with the results of this research [20]. According to Kuete [43], the activity of plant extracts was classified as significant (MIC < 100 µg/ mL), moderate (100 < MIC ≤ 625 µg/mL), or weak (MIC > 625 µg/ mL); thus, T. majus HYs have a weak activity.…”

“…Hydrosols, also called floral and aromatic waters, are complex mixtures that are mostly used in cosmetics and contain trace amounts of essential oils and other compounds that are soluble in water [18,19]. HYs, as by-products of extraction techniques, are often misclassified as wastewater and neglected/discarded, although they contain very valuable bioactive components [20]. Isolated chemical components from the flowers and leaves of T. majus are usually identified by colorimetric reactions and gas chromatographic analysis combined with mass spectrometry [21].…”