Résumé:
The aim of this study is to determine the chemical composition and the in vitro biological
properties (antioxidant, antimicrobial, anti-inflammatory and anti-diabetic) of two plants
essential oils originated from the north-west of Algeria (Tlemcen) (Ammoïdes (or Ptychotis)
verticillata (Desf.) Briq. and Thymus munbyanus subsp. ciliatus (Desf.) Greuter & Burdet);
and also commercial Curcuma longa. The chemical composition was determined using gas
chromatography coupled to mass spectrometry. Different tests were used to evaluate in vitro
the antioxidant activity. The antimicrobial activity was evaluated by the disc diffusion method
and the minimal inhibition concentration was determined by the microdilution method. The
effect of these essential oils was also studied on lipoxygenase, acetylcholinesterase and alphaamylase.
According to the chemical analysis results, carvacrol is the major compound of T.
ciliatus ssp. eu-ciliatus (71.4%), followed by p-cymene (8.3%) and γ-terpinene (5.9%). Cumin
alcohol represents 44.3% of the essential oils of A. verticillata, γ-terpinene (18,1%), limonene
(14,2%) and thymol (10,8%). The major compound of C. longa was aromatic tumerone (35%),
Curlone (14,2%) and tumerone (11,8%). The essential oils of T. ciliatus exhibit a good
antimicrobial activity against Staphylococcus aureus (12.5 to 13.83 mm), Listeria
monocytogenes (13.83 to 22.5 mm), Escherichia coli (13.79 to 14.67 mm) and Salmonella
Thyphimurium (15.67 mm). These essential oils had also a good activity against the hydroxyl
radical (IC50=0,00221mg/ mL), Oxygen Radical Antioxidant Capacity or ORAC (IC50 =1,19
mM Trolox/g), and also inhibited the activity of both enzymes acetylcholinesterase and alphaamylase.
On the other hand the anti-radical activity of the essential oils of A. verticillata were
effective against DPPH (IC50=0,0422mg/mL), ABTS (IC50=0,0013 mg/mL), TBARS
(IC50=0,0279 mg/mL). But the most powerful effect was on H2O2 (IC50=0,522mg/ml). It has a
good reducing property and ability to protect the liposomal membranes
against lipid peroxidation (IC50=0,299 mg/mL). The essential oils of C. longa had a good
capacity of lipoxygenase inhibition (IC50=0,013 mg/mL). The anti-tumor activity of T. ciliatus
against cancer cells THP-1 was higher than A. verticillata. These essential oils showed an
interesting biological properties that should be investigated in vivo.
