Composition and pharmacological activity of essential oils from two imported Amomum subulatum fruit samples

This work attempted to isolate, identify, and correlate the composition of essential oils (EOs) and pharmacological properties of two imported Amomum subulatum fruit samples. These samples were collected from Indian and KSA local supermarkets to ensure consistency in their therapeutic effects.

EOs were extracted from Indian and KSA A. subulatum fruit samples using a hydro-distillation method and identified by gas chromatography-mass spectrometry (GC-MS). Antimicrobial activity against gram-negative bacteria (Pseudomonas aeruginosa, Escherichia coli, and Acinetobacter baumannii) was determined using minimum inhibitory (MIC) and minimum bactericidal concentration methods. Antioxidant and anti-inflammatory activities were determined using a 2,2-diphenyl-1-picrylhydrazyl-induced free radical assay, and a bovine albumin inhibitory assay, respectively. These analyses were performed to evaluate the pharmacological activities of the substances.

GC-MS retention times of both samples demonstrated 56 bioactive ingredients with different percentages. The principal bioactive compounds in the Indian and Saudi Arabian EO samples were 1,8-cineole (44.24% and 46.22%, respectively), α-terpineol (7.47% and 7.04%, respectively), terpinen-4-ol (5.01% and 4.83%, respectively), geraniol D (4.05% and 3.54%, respectively), and β-pinene (3.38% and 3.98%, respectively). Superior antimicrobial activity against the selected strains was observed for both samples, with an MIC range of 0.5%-1%. Antioxidant assays demonstrated moderate activity in both samples. Moreover, the Indian and Saudi Arabian samples exhibited IC₅₀ values of 53.12% and 55.26 μg/mL, respectively, in albumin denaturation inhibition assays. This indicated an outstanding anti-inflammatory potential comparable to ibuprofen.

The composition of EOs from both samples exhibited similar qualitative but different quantitative variability. No major variations in the pharmacological properties of EOs were observed. More studies are essential for further validation of our study findings.