Tetraclinis articulata (Vahl) Mast. essential oil as a promising source of bioactive compounds with antimicrobial, antioxidant, anti-inflammatory and dermatoprotective properties: In vitro and in silico evidence

Abstract

Tetraclinis articulata is a known traditional medicinal plant used to manage various ailments, such as diabetes, rheumatism and infectious diseases. This study aims to determine the chemical constituents of T. articulata essential oil (EO) and to evaluate its in vitro antibacterial, anti-candidal, antioxidant, anti-inflammatory and dermatoprotective properties. In addition, a computational docking approach was used to predict the potential antioxidant, antibacterial, antifungal, anti-inflammatory, and cytotoxic properties of the identified compounds. The volatile oil obtained by hydrodistillation was characterized using gas chromatography-mass spectrometry (GC-MS). The antioxidant activity of T. articulata EO was investigated using three complementary assays: DPPH, ABTS and FRAP. Lipoxygenase (5-LOX) and tyrosinase enzymes were used to assess the anti-inflammatory and dermatoprotective effects of this oil. Moreover, disc-diffusion technique, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assays were employed for the antimicrobial screening. The GC-MS analysis revealed that bornyl acetate (41.80 %), α-pinene (17.97 %) and camphor (15.97 %) are the major components of the studied EO. Moreover, T. articulata EO has exhibited promising antioxidant effect on FRAP, DPPH, and ABTS experiments. It also significantly inhibited 5-LOX (IC₅₀ = 67.82 ± 0.03 μg/mL) and tyrosinase (IC₅₀ = 211.93 ± 0.02 μg/mL). The results of MIC and MBC assays indicated that T. articulata EO is able to inhibit the growth of all tested bacteria (Gram + and Gram -) and Candida species. The ratio of tolerance level indicated that the tested oil was bactericidal against the Gram + bacteria and Candida species, whereas it has a bacteriostatic behavior against the Gram^- bacteria. In light of these findings, T. articulata EO may be suggested as a potential pharmaceutical agent to prevent inflammation and skin problems and may serve as a natural antimicrobial and antioxidant alternative for sustainable application in food products.

Keywords: Biological activities; GC-MS profiling; Microbial resistance; Molecular docking; Tetraclinis articulata.

Fig. 1

Antimicrobial activity of TAEO against (a) bacteria and (b) Candida pathogenic species compared to commercialized drugs (Chloramphenicol, Kanamycin, Fluconazole, Clotrimazole) using disc-diffusion method. Data are represented as means ± SD of three replicates; diameter of inhibition zone including disc diameter of 6 mm.

Fig. 2

Antioxidant properties of TAEO, (a) IC₅₀ of DPPH assay, (b) IC₅₀ of ABTS assay, (c) EC₅₀ of ferric reductive power test. Data with the same letter in the same assay indicates a non-significant difference by Tukey's multiple range test (ANOVA, p < 0.05). Values are expressed as means ± SD of three independent repetitions.

Fig. 3

Two-dimensional (2D) molecular interactions of (a) bornyl acetate, (b) α-terpinyl acetate, (c) α-copaene, (d) caryophyllene, and (e) ciproflaxacine (reference compound) with Dihydrofolate reductase (PDB ID: 4M6J), (resolution, 1.20 Å), (root mean square deviation) RMSD <1.

Fig. 4

Two-dimensional (2D) molecular interactions of (a) bornyl acetate, (b) fluconazol (reference compound) with Cytochrome P450 alpha-sterol demethylase (PDB ID: 1EA1), (resolution, 2.21 Å), (root mean square deviation) RMSD <1.

Fig. 5

Two-dimensional (2D) molecular interactions of (a) bornyl acetate, (b) α-copaene, and (c) caryophyllene, and (d) protocatechuic acid (reference compound) with lipoxygenase (PDB ID: 1N8Q), (resolution, 2.10 Å), (root mean square deviation) RMSD <1.

Fig. 6

Two-dimensional (2D) molecular interactions of (a) bornyl acetate, (b) α-copaene, and (c) hydroquinone (reference compound) with tyrosinase (PDB ID), (resolution, 2.20 Å), (root mean square deviation) RMSD <1.

Fig. 7

Two-dimensional (2D) molecular interactions of (a) bornyl acetate, (b) α-copaene, (c) caryophyllene, and (d) BHT (reference compound) with glutathione reducatase (PDB ID: 3GRS), (resolution, 1.54 Å), (root mean square deviation) RMSD <1.