Linalyl acetate

All 23 standard compounds used for the quantification analysis were purchased from Sigma-Aldrich (purity 99.0%, all chromatographic grade), including butanoic acid, acetic acid, thujone, methyl eugenol, p-cymene, α-pinene, diallyl disulphide, α-terpineol, β-caryophyllene, β-myrcene, 1,8-cineole, D-limonene, linalool, methional, nonanal, phenylethanal, ethyl caprylate, 4-methyl-5-thiazoleethanol, (E)-2-octenal, (E)-2-heptenal, humulene, acetophenone, and linalyl acetate. The internal standard (2,4,5-trimethylthiazole) and n-alkanes (C8–C30) used to calculate the retention index (RI) were of chromatographic grade and purchased from Sigma-Aldrich (St, Louis, MO, USA). Diethyl ether and n-pentane for dilution and preparation of sample were obtained from Thermo Fisher Scientific Inc. (Waltham, MA, USA). High purity helium (99.999% purity) and nitrogen (99.99% purity) were purchased and produced by Beijing Tianlirenhe Trading Co., Ltd. (Beijing, China).

Materials used in this study were purchased in India. Cyclophosphamide, linalool, linalyl acetate, and albumin 5% solution were from Sigma Aldrich; Imiquimod (IMQ) cream (5%) was the product of Glenmark Pharmaceuticals Ltd.; Polyethylene glycol 200 (PEG200), alcohol, hematoxylin, eosin, DPX mountant, and xylene were from Thomas Baker; Paraffin wax (60–62°C) was from Merck; ELISA Kits (TNF-α, IL-1β, and IL-6) were from Invitrogen Bio-services; IL-17 A and IL-22 were from Koma Biotech; NF-κB, IL-17, and cck6 specific primary and secondary antibodies were from Santa Cruz, and hydrogen peroxide (H₂O₂; 30%) and DAB chromogen were from TCI Chemicals. The solvents and chemicals used in the study were of analytical grade. We used Milli-Q water throughout the study.
The product specification and description of the linalool (Catalog number W263516) and linalyl acetate (Catalog number W263613) are given in Supplementary Material S1, Supplementary Figure S1; Buchbauer et al. (1991) (link). The combination of the phyto-molecules used in this investigation is endotoxin-free.

The β-lactam antibiotics (Figure 4) methicillin sodium salt (≥95% purity) and penicillin G sodium salt (>96% purity) were purchased from Sigma-Aldrich (Darmstadt, Germany). Concentrations of the antibiotics from 1000 to 0.12 mg/L were prepared by dissolving the medicines in 2% (v/v) dimethyl sulfoxide (DMSO, Loba Chemie, Mumbai, India) and diluting with Mueller–Hinton broth (MHB; Sigma-Aldrich, Darmstadt, Germany).
The ten EOCs (Figure 4) used in this study, 1,8-cineole (99% purity), eugenol (≥98% purity), linalool (≥96% purity), linalyl acetate (≥97% purity), thymol (≥99% purity), menthone (98% purity), menthol (>99% purity), and β-caryophyllene (>95% purity), were purchased from ErnestoVentós, S.A. (Barcelona, Spain), whereas carvacrol (99% purity) and trans-anethole (99% purity) were obtained from Sigma-Aldrich (Darmstadt, Germany). Concentrations of the EOCs from 500 to 0.12 µL/mL were prepared by dissolving constituents in 1% (v/v) Tween 80 (Sigma-Aldrich, Darmstadt, Germany) and diluting with MHB. Using the known densities of EOCs, the results were expressed in mg/mL.

Dichloromethane was obtained from Avantor Performance Materials Poland S.A. company (purity 99.8%). The standard substances (linalool, linalyl acetate, lavandulyl acetate, (-)-bornyl acetate, (-)-trans-caryophyllene, and geraniol) had a purity of 93.0 to 99.3% and were purchased from Sigma-Aldrich Sp. Z o.o. (Poznan, Poland). Two lavender oils were analyzed: the first one was our in-house preparation, developed at the Cracow University of Technology (LO-SM), and the second was commercially available lavender oil (LO-C).

1,8 cineole, linalool and linalyl acetate with a purity > 97%, terpinyl acetate (mixture of two isomers) with a purity > 95%; β-caryophyllene (mixture of two isomers) with a purity > 98.5%,decane (purity >99%) high purity silica gel 70–230 mesh and silver nitrate on silica gel (about 10% wt, % loading + 230 mesh) were from Sigma-Aldrich (Milan, Italy). HPLC and analytical grade solvents were from Carlo Erba Reagenti (Rodano, Italy). Commercially available standards were chosen to confirm component identification in the essential oil and to quantify the EO components on the basis of their response factor towards an internal standard (decane) considering the potential shift of FID towards the different classes of compounds [21 ]. Acyclovir, used as a positive control for HSV-2 antiviral activity was purchased from Sigma-Aldrich (Milan, Italy).

The EOs have directly been purchased from Azienda Agricola Aboca (Sansepolcro, Arezzo) as steam distilled samples obtained from Thymus vulgaris L. (thyme red), Foeniculum vulgare Mill. var. dulce DC (fennel), Eugenia caryophyllata Thumb. (clove), Pinus sylvestris L. (pine), Salvia officinalis L. (sage), Melissa officinalis L. (lemon balm) and Lavandula vera DC (lavender). The components carvacrol, eugenol, linalool, linalyl acetate, thymol and α-pinene (≥98 % purity) were supplied by Sigma Aldrich (Steinheim, Germany) and used as received without any further purification. EOs and related components were storage at 4 °C until use.