Detection and identification of antibacterial and antioxidant components of essential oils by TLC-biodetection and GC-MS

Abstract

Components of cinnamon bark, rosemary, clove and thyme essential oils were screened for antioxidant and antibacterial activity utilizing thin-layer chromatography (TLC) coupled with the DPPH• test and direct bioautography using Bacillus subtilis cells. The compounds in the active chromatographic zones were identified by solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) after their elution. Seven antibacterial components were found: cinnamaldehyde and eugenol in cinnamon bark oil, 1,8-cineole, camphor, borneol and α-terpineol in rosemary oil, eugenol in clove oil and thymol in thyme oil. Only two of them, thymol and eugenol displayed a free radical scavenging effect.