Chemical composition, antioxidant and antimicrobial activity of Thymus praecox supercritical extracts

• Supercritical extracts of Thymus praecox ssp. polytrichus were studied.
• Thymol (29.36% and 16.46%) was the main component in supercritical extracts.
• Supercritical extracts showed stronger antimicrobial activity than control.
• MIC varied from 38 to 200 μg/ml for bacteria, and from 17 to 150 μg/ml for fungi.
• Supercritical extracts showed lower antioxidant activity than BHA and BHT.

The chemical composition, antimicrobial and antioxidant activity of Thymus praecox extracts obtained by fractional supercritical fluid extraction (SFE) with carbon dioxide were investigated. Properties of supercritical extracts and extracts obtained by Soxhlet extraction were compared. The chemical composition of extracts was determined using GC–FID and GC–MS analytical methods. The antimicrobial activity of extracts was evaluated against 16 pathogenic microorganisms using microdilution method. Antioxidant potential of extracts to neutralize DPPH radicals was also investigated. Investigated supercritical extracts showed better antimicrobial activity than commercial antibiotics (streptomycin and ampicillin) and commercial fungicides (bifonazol and ketoconazole) against all tested strains. For bacteria MIC and MBC were 38–200 μg/ml and 75–300 μg/ml, respectively, while for fungi MIC and MFC were 17–150 μg/ml and 35–300 μg/ml, respectively.

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