GC-MS characterization and biological activities of the essential oil from Tambourissa trichophylla leaves (Monimiaceae)

Abstract

The present study aimed to evaluate the chemical composition as well as the antimicrobial and antioxidant activities of the essential oil extracted from the leaves of Tambourissa trichophylla (Monimiaceae), collected in the humid forest of Ranomafana National Park, Madagascar. The essential oil (TTEO) was obtained by steam distillation from fresh leaves with a yield of 0.65%. TTEO appeared as a clear yellow liquid with a pleasant odor, exhibiting a relative density of 0.8921 at 20 °C, a refractive index of 1.4728, an optical rotation of -29°45, an acid index of 0.621, and an ester index of 6.142. Gas chromatography coupled with mass spectrometry (GC-MS) analysis allowed the identification of 29 constituents, representing 99.74% of the total composition. The major compound was sabinene (28.47%), followed by other compounds present at proportions higher than 5%, including limonene (16.85%), methyl eugenol (12.63%), and α-pinene (9.12%). The antibacterial activity was evaluated against nine pathogenic microorganisms (four Gram-positive bacteria, four Gram-negative bacteria, and one yeast) using disk diffusion and microdilution methods. TTEO showed inhibition zone diameters (IZD) ranging from 9.2 mm (Bacillus cereus) to 13.4 mm (Clostridium perfringens). The minimum inhibitory concentration (MIC) ranged from 1.05 to 2.10 mg/ml, while the minimum bactericidal concentration (MBC) was 8.40 mg/ml for all tested strains. TTEO exhibited a bacteriostatic effect against Streptococcus pneumoniae, Clostridium perfringens, Bacillus cereus, and Candida albicans (MBC/MIC > 4), and a bactericidal effect against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Salmonella typhi, and Vibrio fischeri (MBC/MIC ≤ 4). Furthermore, the essential oil demonstrated free radical scavenging activity against DPPH, with an IC₅₀ value of 118.75 mg/ml. Oral administration in mice resulted in an LD₅₀ value of 1.75 g/kg body weight, indicating relatively low acute toxicity.