Broad-spectrum bioactivities and therapeutic potential of essential oils of certain aromatic and medicinal plants and their combination

Abstract

This research investigates the bioactive properties of essential oils obtained from three medicinal and aromatic species: Mentha canadensis, Corymbia citriodora, and Plectranthus amboinicus. The essential oils were evaluated for antiviral, antioxidant, anticancer, and antidiabetic activities. The gas chromatography-mass spectrometry (GC-MS) examination identified a variety of phytochemical constituents, including thymol, citronellol, and levomenthol. Cytopathic impact studies indicated that M. canadensis and C. citriodora oils attained a maximum of 35.34% suppression of Adeno 7 virus replication. The oils exhibited minimal cytotoxicity in Vero cells, with viability exceeding 97% at concentrations of ≤ 312 µg/mL. P. amboinicus oil had the highest cytotoxicity against H1299 lung cancer cells (IC₅₀ = 11 µg/mL), indicating significant anticancer efficacy. The antidiabetic effects were evidenced by α-glucosidase inhibition, with P. amboinicus oil displaying the greatest activity (IC₅₀ = 248.1 µg/mL). The DPPH experiment demonstrated that P. amboinicus exhibited the highest antioxidant activity (IC₅₀ = 5923 µg/mL). The results highlight the medicinal potential of these essential oils, including P. amboinicus for anticancer, antioxidant and antidiabetic applications, and C. citriodora and M. canadensisfor antiviral purposes. The current work serves about four goals of the sustainable development goals (SDG) as follow: SDG 3: Good Health and Well-being, SDG 12: Responsible Consumption and Production, SDG 9: Industry, Innovation, and Infrastructure and SDG 15: Life on Land.

Keywords: Corymbia citriodora; Mentha canadensis; Plectranthus amboinicus; Anticancer; Antidiabetic; Antioxidant; Antiviral; Essential oil; GC–MS.

Fig. 1

In vitro culture of three fragrant and medicinal plants (a. Mentha canadensis, b. Corymbia citriodora, and c. Plectranthus amboinicus).

Fig. 2

Gas chromatography-mass spectrometry (GC–MS) chromatograms of compounds present in essential oils of (a) M. canadensis, (b) C. citriodora and (c) P. amboinicus.

Fig. 3

Cytotoxicity of (1) Mentha canadensis, (2) Corymbia citriodora, (3) Plectranthus amboinicus essential oils and (4) their combination on Vero cells, as determined using MTT assay. Vero cells (ATCC, CCL-81) were cultivated in DMEM supplemented with 10% FBS and antibiotics at 37 °C in a 5% CO₂ atmosphere. Cells (1 × 10⁴/well) in 96-well plates were subjected to treatment with 4.88–10,000 µg/mL of M. canadensis, C. citriodora, P. amboinicus essential oils, or their combination for a duration of 24 h. MTT reagent (5 mg/mL) was administered for 4 h, formazan was dissolved in DMSO, and absorbance was measured at 570 nm. Cell viability was assessed in comparison to untreated controls. (n = 3 replicates; plotted values represent mean ± standard deviation (SD)).

Fig. 4

Antiviral activity of (1) Mentha canadensis, (2) Corymbia citriodora, (3) Plectranthus amboinicus essential oils and their combination (4) against Adeno7 virus, evaluated using cytopathic inhibition assay, with oil concentration of 625 µg/ml. (A: TPT value (titer post treatment), B: %red value (percentage of reduction). (n = 3 replicates, plotted values represent mean ± standard deviation (SD)).

Fig. 5

H1299 human non-small cell lung cancer cells were grown in RPMI-1640 media supplemented with 10% FBS and antibiotics at 37 °C and 5% CO₂. Cells (5 × 10³/well) were placed in 96-well plates, let to grow for 24 h, and then treated with a series of dilutions of M. canadensis, C. citriodora and P. amboinicus, essential oils, as well as a mix of the three for 72 h. The control (100% vitality) was cells that had not been treated. The SRB assay was used to measure cytotoxicity, and dose–response curves were used to find IC₅₀ values. (n = 3 replicates).

Fig. 6

Inhibition of alpha glucosidase enzyme by (2) Corymbia citriodora, (3) Plectranthus amboinicus essential oils and their combination (4), where the concentration-dependent inhibition by the oils is compared against acarbose. (n = 3 replicates).

Fig. 7

Radical scavenging activity of (2) Corymbia citriodora, (3) Plectranthus amboinicus essential oils and their combination (4) against DPPH radical (%). (n = 3 replicates).