Essential oils from Cupressus arizonica Greene: Chemical composition, antimicrobial and antienzymatic activity

The aims of present study were to determine the chemical composition of the essential oils (EOs) isolated from leaves, stems, and cones of Cupressus arizonica Greene and to evaluate their in vitro antimicrobial, antioxidant and anti-enzymatic effects. The chemical composition was studied by GC-MS. The leaves EO was rich in α-pinene (17.63%), umbellulone (8.21%) and limonene (7.03%). α-Pinene (23.10%) and α-cubebene (6.12%) were the main components of cones EO, whereas stems EO was mainly composed of α-pinene (72.97%). The three EOs were evaluated for their antibacterial and antibiofilm activities against both Gram- positive (Staphylococcus aureus and Listeria monocytogenes) and Gram-negative (Pseudomonas aeruginosa, Escherichia coli and Acinetobacter baumannii) bacterial strains. The EOs showed a high bactericidal potential and an inhibition of the metabolic activities of mature biofilm was noted for all the bacterial strains studied. In particular, leaves EO was able to achieve 53.32% metabolic inhibition against L. monocytogenes at the lowest concentration used. The EOs were also tested for their possible antioxidant and anti-enzymatic activities by spectrophotometric assays. The results showed that the leaves EO showed the best radical scavenging activity and was the most active against α-glucosidase (IC50 = 1.88 mg/mL). The cones EO resulted more active against acetyl-cholinesterase (IC50= 1.15 mg/mL) and α-glucosidase (IC50= 0.85 mg/mL) demonstrating its potential as a coadjutant in treatment of Alzheimer’s and Parkinson’s disease and/or in diabetes. Moreover, kinetic study of cones EO on α-glucosidase showed that inhibition was of competitive-type, like acarbose, those could probably enhance the activity of this drug reducing doses.