Chemical Constituents, Antioxidant, Antimicrobial and Insecticidal Activities of the Essential Oils Extracted from Thymus guyonii de Noé and Thymus algeriensis Boiss. et Reut.

Abstract

This study was designed to determine the chemical composition, antioxidant, antimicrobial and insecticidal activities of essential oils of Thymus guyonii and Thymus algeriensis. The essential oils (EOs) were isolated by hydrodistillation and analyzed by GC and GC-MS. The leading components of the oils were p-cymene (15.8%), γ-terpinene (15.3%), thymol methyl ether (15.7%) and thymol (19.1%) for T. guyonii and α-pinene (4.4%), camphor (4.6%), bornyl acetate (5.4%) and terpinenyl actate (28.1%) for T. algeriensis. The antioxidant activity was evaluated in terms of scavenging of free radicals DPPH^● and ABTS^●+. The essential oil of T. guyonii was the most efficient in inhibiting free radicals but less active compared to synthetic antioxidants (Trolox and BHT). Also, T. guyonii essential oil showed the highest effectiveness against the rice weevil, Sitophilus oryzae L. (Coleoptera: Curculionidae) as well as against five microorganisms, two gram-positive (Staphylococcus aureus and Bacillus subtilis), one gram-negative (Escherichia coli), one yeast (Candida albicans) and one fungus (Aspergillus brasiliensis). The results suggest that the EO of T. guyonii could be considered in pharmaceutical and food fields as well as for preservation of stored products from S. oryzae damage.

Keywords:

• Chemical composition
• Thymus guyonii
• T. algeriensis
• Biological activity
• Sitophilus oryzae