Exploring the Bioactive Potential and Chemical Profile of Schinus molle Essential Oil: An Integrated In Silico and In Vitro Evaluation

Abstract

Chilean Schinus molle has been used in traditional medicine for effects such as antibacterial, antifungal, anti-inflammatory, analgesic, antiviral, antitumoral, antioxidant, antispasmodic, astringent, antipyretic, cicatrizant, cytotoxic, diuretic, among others. In this study, we evaluated the pharmacological potential of Schinus molle seed essential oil extract (SM_EO) through in vitro and in silico approaches. In vitro, the antioxidant potential was analyzed, and antitumor activity was evaluated in non-tumor and human epithelial tumor cell lines. Caenorhabditis elegans was used as a model for evaluating toxicity, and the chemical composition of the SM_EO was analyzed using gas chromatography-mass spectrometry. The oil contained four major monoterpenes: α-phellandrene (34%), β-myrcene (23%), limonene (13%), and β-phellandrene (7%). Based on quantum mechanical calculations, the reactivity of the molecules present in the SM_EO was estimated. The results indicated that α- phellandrene, β-phellandrene, and β-myrcene showed the highest nucleophilic activity. In addition, the compounds following these as candidates for antioxidant and antiproliferative activities were α-phellandrene, β-phellandrene, ρ-cymene, sabinene, caryophyllene, l-limonene, and α-pinene, highlighting β-myrcene. Based on ADME-Tox properties, it is feasible to use these compounds as new drug candidates. Moreover, the antibacterial activity MIC value obtained for B. cereus was equivalent to 2 μg/mL, and for Y. enterocolitica, S. enteritidis, and S. typhimurium, the MIC value was 32.5 μg/μL. SM_EO could selectively inhibit the proliferation of human epithelial mammary tumor MCF7 cells treated with SM_EOs at 64 and 16 ug/mL-a significant increase in BCL-2 in a dose-dependent manner-and showed low toxicity against Caenorhabditis elegans (from 10 to 0.078 mg·mL^-1). These findings suggest that SM_EO may be a potential source of bioactive compounds, encouraging further investigation for applications in veterinary medicine, cosmetics, and sanitation.

Keywords: Caenorhabditis elegans; Schinus molle; antimicrobial activity; antioxidant; antiproliferative; chemical composition; essential oil; toxicity.

Figure 1

Chromatography profile of SM_EO. The peaks observed correspond to the major chemical compounds, mainly monoterpenes.

Figure 2

Isosurface representation of the electrophilic f⁻, radical f⁰, and nucleophilic f⁺ Fukui functions and molecular electrostatic potential maps generated with electron density for SM_EO molecules. Electrostatic potentials are mapped on the surface of the electron density of 0.01 a.u. The red surface corresponds to a negative region of the electrostatic potential (−0.001 a.u.), whereas the blue color corresponds to the region where the potential is positive (0.009 a.u.).

Figure 3

Physicochemical property analysis using bioavailability radar plot representations for SM_EO molecules. The shaded area represents the range of properties to be considered drug-like. The blue line represents the properties of the test molecules. The radar plot angles represent the following: molecular weight (MW), logarithm of n-octanol/water (LogP), logarithm of aqueous solubility (LogS), logarithm of n-octanol/water at pH = 7.4 (LogD), number of hydrogen bond acceptors (nHA), number of hydrogen bond donors (nHD), topological polar surface area (TPSA), number of rotatable bonds (nRot), number of rings (nRing), number of atoms in the biggest ring (MaxRing), number of heteroatoms (nHet), formal charge (fChar), and number of rigid bonds (nRig).

Figure 4

Heatmap of the Lipinski, Pfizer, GlaxoSmithKline (GSK), and Golden Triangle rules offers a comprehensive assessment of the drug likeness of SM_EO molecules. Each cell in the heatmap corresponds to a specific compound and indicates its adherence to the respective rules. Green cells signify full compliance with the rules, indicating acceptance, while red cells denote non-compliance with any of the rules, signaling rejection for drug-likeness analysis.

Figure 5

Heatmap illustrating the main toxicological indices of SM_EO molecules, providing a comprehensive overview of their potential safety profiles. Each cell in the heatmap corresponds to a specific compound and displays prediction probability values categorized into six intervals: 0–0.1 (−−−), 0.1–0.3 (−−), 0.3–0.5 (−), 0.5–0.7 (+), 0.7–0.9 (++), and 0.9–1.0 (+++). These values signify the likelihood of toxicity, with lower probabilities indicating a lower risk (−−−) and higher probabilities suggesting a higher risk (+++). To facilitate interpretation, the heatmap utilizes a color scheme: green represents the lowest prediction probability; yellow indicates medium-to-normal prediction probability; and red highlights the highest prediction probability.

Figure 6

Proliferation assay of human epithelial tumor and non-tumor cells from: mama breast MCF10A (a) and MCF7 (b) and kidney 786-O (d), ACHN (e), and HK-2 (c) treated with vehicle (DMSO 1%) or SM_EO at different concentrations for 48 h, evaluated by via CV assay at 570 nm. The graph bar represents the mean +SEM of the values by obtained triplicate of from three independent experiments performed in triplicate independent per each treatment, the *** represent a p < 0.001. In the MCF10A cell line (a), the p value was 0.062.

Figure 7

Cell cycle proteins expression of MCF7 cells treated with SM_EOs at different concentrations. Western blot iThe images of the western blot shown the present presence and abundance of BCL-2 (a), P53 (b), and RB (c) proteins on in the cells treated with vehicle (DMSO 1% or SM_EOs) for 48 h, evaluated by via CV assay at 570 nm. The graph bar represents the mean +SEM of the values, quantified by Fiji Image J software (x86-64), by obtained from three independent experiments performed in triplicate of three experiments independent per each treatment.

Figure 8

Percent survival of Caenorhabditis elegans exposed to SM_EO for 24 h (a) and 48 h (b).