Data on cytotoxicity of plant essential oils in A549 and Detroit 551 cells

To secure the safety for industrial applications of plant essential oils, it is necessary to determine the inhibitory concentration and inhibitory mechanism of cell proliferation in skin cells and lung cells. Considering inhalation through the respiratory system and skin contact of humans with essential oils, we used human lung cancer cells A549 and human skin fibroblasts Detroit 551 cells for all experiments. In this study, we examined IC50 values and protein levels of cell cycle markers (cyclin A, cyclin B, cyclin D, and cyclin E) and apoptosis marker (caspase-3) after exposure to 10 plant essential oils, including Dendranthema indicum (L.) Des Moul, Peucedanum japonicum Thunb, Dendranthema zawadskii var. latilobum (Maxim.) Kitam, Agastache rugosa (Fisch.&Mey.) Kuntze, Vitex rotundifolia L.f, Pinus rigida Mill; Orixa japonica Thunb, Pinus strobus L, Chamaecyparis pisifera (Siebold et Zucc.) Endl. var. filifera Beissn. et Hochst, and Citrus sunki Hort. ex Tanaka. After the treatment of A549 and Detroit 551 cells to varying concentrations of the 10 plant essential oils, IC50 values were determined by CCK analysis, whereas protein expressions of the four cyclins and caspase-3 were identified by Western blotting analysis. We believe that by examining the degree and mechanism of cell proliferation inhibition exerted by essential oils on skin and lung cells of humans, data obtained in this study can provide guidelines for the industrial application of plant essential oils.


a b s t r a c t
To secure the safety for industrial applications of plant essential oils, it is necessary to determine the inhibitory concentration and inhibitory mechanism of cell proliferation in skin cells and lung cells. Considering inhalation through the respiratory system and skin contact of humans with essential oils, we used human lung cancer cells A549 and human skin fibroblasts Detroit 551 cells for all experiments. In this study, we examined IC 50 values and protein levels of cell cycle markers (cyclin A, cyclin B, cyclin D, and cyclin E) and apoptosis marker (caspase-3) after exposure to 10 plant essential oils, including Dendranthema indicum (L.) Des Moul, Peucedanum japonicum Thunb, Dendranthema zawadskii var. latilobum (Maxim.) Kitam, Agastache rugosa (Fisch.&Mey.) Kuntze, Vitex rotundifolia L.f, Pinus rigida Mill ; Orixa japonica Thunb, Pinus strobus L, Chamaecyparis pisifera (Siebold et Zucc.) Endl. var. filifera Beissn. et Hochst, and Citrus sunki Hort. ex Tanaka. After the treatment of A549 and Detroit 551 cells to varying concentrations of the 10 plant essential oils, IC 50 values were determined by CCK analysis, whereas protein expressions of the four cyclins and caspase-3 were identified by Western blotting analysis. We believe that by examining the degree and mechanism of cell proliferation inhibition exerted by essential oils on skin and lung cells of hu-mans, data obtained in this study can provide guidelines for the industrial application of plant essential oils.
© 2020 The Author(s Value of the data • This data provides guidelines and safety for industrial applications of plant essential oils.
• This data may be useful to understand the IC 50 values of plant essential oils in A549 and Detroit 551 cells. • This data could be actively used for determining molecular mechanisms of the cell cycle and apoptosis of plant essential oils in the A549 and Detroit 551 cells. • The data obtained can support researchers in the field of molecular mechanisms of plant essential oils, and individuals who work with plants.

Data
Essential oils are secondary metabolites produced by plants that are highly aromatic and are a mixture of various components. Essential oils contain numerous monoterpenes and sesquiterpenes and can be obtained from the flowers, leaves, stems, and roots of plants [1] . Essential oils have a variety of applications in several areas, such as preservatives, antioxidants, and perfumes [ 2 , 3 ]. Considering the wide applications, we examined cytotoxicity and protein marker data in A549 and Detroit 551 cells.
The cell survival and cytotoxicity IC 50 values of 10 essential oils were also examined in Detroit 551 cells using CCK-8 analysis ( Fig. 2 , Table 2

Plants essential oils
The

Cell culture
All cell culture assays were performed as per the protocols suggested by Ahn [4] . Human lung cancer cells A549 and human skin fibroblasts Detroit 551 cells were purchased from Korea Cell Line Bank (KCLB, Seoul, Republic of Korea). Cells were cultured in DMEM high-glucose media (Biowest, France) supplemented with 5% penicillin-streptomycin solution (Biowest, France) and 10% fetal bovine serum (FBS) at 37 °C in a 5% CO 2 humidified culture incubator (Sanyo, Japan).

Cell proliferation assay
To determine cell survival after exposure to essential oils, 40 0 0 cells per well were seeded in a 96-well plate and incubated for 24 h. Fresh medium was added to the cultured cell plates, and cells were subsequently treated to varying concentrations of essential oils. The plant essential oils were diluted to 0.001%, 0.01%, 0.1%, and 1% concentrations with 0.1% DMSO-plus 5% DMEM media (specimen volume/media volume). After further incubation 24 h, plant essential oils and media were removed, and treated cells were washed twice with DPBS (WELGENE, Korea), followed by the addition of the concentration of EZ-Cytox enhanced cell viability assay reagent (DoGenBio, Korea), and allowed to react for 1 h. Absorbance values were measured at 450 nm using an Epoch microplate spectrophotometer (BioTek, USA). From the obtained values, cell survival curves were calculated using Excel and prism (v.5.0; GraphPad Software, USA), and IC 50 values were determined.

Statistical analysis
All experiments consisted of three separate trials. Using the four-parameter logistic analysis (Sigmoidal), IC 50 values were determined for each essential oil. The western blot data were expressed as the mean ± SEM and analyzed by one-way analysis of variance (ANOVA) followed by Tukey's multiple comparison tests. Statistical analysis was performed by using Graph Pad Prism (version 5.01, GraphPad Software).

Declaration of Competing Interest
The authors declare that they have no known competing for financial interests or personal relationships that could have appeared to influence the work reported in this paper.