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

Stefania Garzoli; Valentina Laghezza Masci; Sara Franceschi; Antonio Tiezzi; Pierluigi Giacomello; Elisa Ovidi

doi:10.3390/foods10081768

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

Foods. 2021 Jul 30;10(8):1768. doi: 10.3390/foods10081768.

Authors

Stefania Garzoli¹, Valentina Laghezza Masci², Sara Franceschi³, Antonio Tiezzi², Pierluigi Giacomello¹, Elisa Ovidi²

Affiliations

¹ Department of Drug Chemistry and Technology, Sapienza University, 00185 Rome, Italy.
² Department for the Innovation in Biological, Agrofood and Forestal Systems, Tuscia University, 01100 Viterbo, Italy.
³ Department of Economics and Statistics, University of Siena, 53100 Siena, Italy.

Abstract

In this work, essential oils (EOs) and hydrolates (Hys) of Rosmarinus officinalis L. and Lavandula angustifolia Mill., grown in Tuscany (Italy), were studied to describe their chemical composition and biological activities. The aromatic profile of the EOs liquid phase was carried out by gas chromatography-mass spectrometry (GC-MS), while the volatile composition of vapor phase EOs and Hys was performed by headspace (HS)/GC-MS. The obtained results show that monoterpene hydrocarbons (71.5% and 89.5%) were the main compounds, followed by oxygenated monoterpenes (26.0% and 10.5%) in the liquid and vapor phase of R. officinalis EO, respectively. The oxygenated monoterpenes were the main components of L. angustifolia EO, reaching 86.9% in the liquid phase and 53.7% in the vapor phase. Regarding Hys, they consisted only of oxygenated monoterpenes, and 1,8-cineole (56.2%) and linalool (42.9%), were the main components of R. officinalis and L. officinalis Hys, respectively. Their cytotoxicity was investigated on an SHSY5Y neuroblastoma cell line by thiazolyl blue tetrazolium bromide (MTT) test, showing a notable effect of the EOs with a time-independent manner of activity and half maximal effective concentration (EC₅₀) values quite similar for the two plant species (from 0.05% to 0.06% v/v for the three time points evaluated). A measurable activity of Hys was also obtained although with higher EC₅₀ values. The antibacterial activity against Escherichia coli ATCC^® 25922, Pseudomonas fluorescens ATCC^® 13525, Acinetobacter bohemicus DSM 102855 as Gram-negative bacteria and Kocuria marina DSM 16420, Bacillus cereus ATCC^® 10876 as Gram-positive bacteria, was evaluated by the agar disk-diffusion method and the VPT (vapor phase test) to determinate the MIC (minimal inhibitory concentration) and the MBC (minimal bactericidal concentration) values. Both EOs possessed a high activity against all the bacterial strains with MIC values ranging from 0.19% to 3.13% v/v. Unlike EOs, Hys did not show an inhibition of the bacterial growth at the tested concentrations. Furthermore, antioxidant power was measured by 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt-based (ABTS•+) and the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays, showing a remarkable ability to reduce radicals by both EOs; Hys were slightly less active. The findings highlighted that R. officinalis and L. angustifolia EOs and Hys have a chemical composition rich in bioactive molecules, which can exert different biological activities.

Keywords: Lavandula angustifolia; Rosmarinus officinalis; biological activity; chemical analysis; essential oils; hydrolates; volatile compounds.