GC/MS Profile and In-Vitro α-Glucosidase Inhibitory Activity of Essential Oil of Eucalyptus camaldulensis Dehnh Collected from (Erbil) Iraq

Background: Eucalyptus camaldulensis Dehnh is abundantly found in Erbil, Iraq and commonly used as an antispasmodic and antipyretic remedy for treating respiratory tract diseases. The present study aimed to evaluate the effectiveness of E. camaldulensis in achieving glucose homeostasis through the inhibition of α-glucosidase enzyme using in-vitro model and also determine the chemical composition of essential oil by gas chromatography mass spectroscopy (GC/MS). Methods: The chemical composition of E. camaldulensis essential oil by was determined by GC/MS and its antidiabetic activity was assessed through inhibition of α-glucosidase enzyme in in- -vitro models. Results: The essential oil yielded 40 chemical constituents amounting to 98.55%. The major constituents of essential oil of E. camaldulensis leaf were 1,8-cineole (28.4%), isocaryophyllene oxide (8.4%), β-ocimene (7.9%), α-farnesene (7.9%), globulol (7.3%), terpinen-4-ol (7.6%), isophytol (3.6%), viridiflorol (3.2%), p-cymen-3-ol (3.1%) and α-bisabolol (1.2%). The essential oil of E. camaldulensis showed concentration-dependent inhibition of α-glucosidase enzyme and the inhibition ranged from 75.38±2.09 to 6.08±1.89% for concentration 100 to 3.125 μg/mL. The α-glucosidase inhibition of E. camaldulensis (IC50 value 16.7±2.61 μg/mL) was found almost comparable with standard drug acarbose (IC50 value 12.04±3.17 μg/mL). Conclusion: The result of this study concluded E. camaldulensis essential oil as having 1,8-cineole, isocaryophyllene oxide and β-ocimene as major constituents; the study findings also confirm the traditional claim of its use in the treatment of diabetes mellitus.