Chemical Composition of Natural Hydrolates and Their Antimicrobial Activity on Arcobacter-Like Cells in Comparison with Other Microorganisms

Abstract

Hydrolates obtained via the hydrodistillation and steam distillation of Lavandulaangustifolia Mill., Syzygiumaromaticum L., Foeniculumvulgare Mill., and Laurusnobilis L. were analyzed by gas chromatography with flame ionization detector (GC-FID) and gas chromatography coupled to mass spectrometry (GC-MS). Additionally, the hydrolates were evaluated for antimicrobial activity (disk-diffusion and microdilution method), influence on biofilm formation (Christensen method) and cytotoxicity of concentrated hydrolates against human cell lines (A549) by xCELLigence system. Using chemical analysis, 48, 9, 13 and 33 different components were detected in lavender, clove, fennel and laurel hydrolates, respectively. Lavender hydrolate contained the largest proportion of 1,8-cineol, linalool furanoxide, and linalool. The main components of laurel hydrolate were 1,8-cineol, 4-terpineol and α-terpineol. Fenchone and estragole were the most abundant in fennel hydrolate, and eugenol and eugenyl acetate in clove hydrolate. Concentrated hydrolates showed significant antimicrobial activity. Clove hydrolate was among the most antimicrobially active agents, most preferably against C. albicans, with an inhibition zone up to 23.5 mm. Moreover, concentrated hydrolates did not show any cytotoxic effect again8 st human A549 cells. In the presence of the non-concentrated hydrolates, significantly reduced biofilm formation was observed; however, with concentrated clove hydrolate, there was an increase in biofilm formation, e.g., of A. thereius, A. lanthieri, and A. butzleri. Research shows new findings about hydrolates that may be important in natural medicine or for preservation purposes.

Headspace/GC–MS Analysis and Investigation of Antibacterial, Antioxidant and Cytotoxic Activity of Essential Oils and Hydrolates from Rosmarinus officinalis L. and Lavandula angustifolia Miller

“…Furthermore, Hys were demonstrated to be active against biofilm production [59,60], and thus could be used as a natural antimicrobial agent for food production [54]. As reported by Šilha et al [53], no antibacterial effect of L. angustifolia Hy was detected against eight strains of Arcobacter-like bacteria and against Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa, Escherichia coli and the yeast Candida albicans. On the contrary, concentrated Hys, obtained by solid-phase extraction and tested against the same microorganisms, exercised a considerable antimicrobial activity.…”

“…Of interest, L. angustifolia Hy from Croatia [53] was characterized by linalool (23.2%) when steam distillation was used to obtain the extract, and by 1,8-cineole (20.6%) through hydrodistillation. In fact, the chemical profile of Hys can also vary according to the distillation method used [54].…”

Effects of Biostimulants on the Chemical Composition of Essential Oil and Hydrosol of Lavandin (Lavandula x intermedia Emeric ex Loisel.) Cultivated in Tuscan-Emilian Apennines

“…Moreover, part of them might derive from the molecular rearrangement of other terpenes during the extraction process. Indeed, the oxides of linalool and α-terpineol were more abundant in the hydrosols than in the EOs, as observed by Šilha et al in Lavandula angustifolia and Baydar et al in Lavandula x intermedia [31,53]. This evidence can be explained by the fact that in boiling water (during the steam distillation) linalool might undergo oxidations and cyclization processes [53].…”

“…Indeed, the oxides of linalool and α-terpineol were more abundant in the hydrosols than in the EOs, as observed by Šilha et al in Lavandula angustifolia and Baydar et al in Lavandula x intermedia [31,53]. This evidence can be explained by the fact that in boiling water (during the steam distillation) linalool might undergo oxidations and cyclization processes [53]. Monoterpene hydrocarbons represented 1-2% of the whole volatile compounds, according to their limited solubility in the aqueous environment.…”

Biofilm Formation Ability of Arcobacter-like and Campylobacter Strains under Different Conditions and on Food Processing Materials

“…Bacteria living in biofilms exhibit increased resistance to host defense mechanisms and up to 1000 times higher natural resistance, e.g., to antibiotics [3,4]. The current trend is also to monitor the influence of many natural substances on the formation of microbial biofilms [5,6]. In nature, we often observe multispecies biofilms created on abiotic or biotic surfaces [7].…”