Chemodiversity and α-Glucosidase Activity of Eucalyptus Species from Northwestern Himalaya, India.

The aim of current work was to determine essential oils (EOs) composition from three Eucalyptus species, including E. citriodora, E. camaldulensis and E. globulus and assess their α-glucosidase inhibitory activity. The EOs were collected using the hydrodistillation technique and characterized by GC/MS, GC-FID and NMR. The isolated EOs from leaves parts of Eucalyptus species varied from 0.56 to 1.0% on fresh weight basis. The content of the EOs was distinct according to the species. The most abundant metabolites were identified as citronellal (0-83.0%), 1,8-cineole (0.2-44.8%), spathulenol (0.4-16.1%) α-pinene (0.4-15.9%), p-cymene (3.7-11.9%), citronellol (0-8.6%), β-eudesmol (5.3-8.6%) and β-pinene (0-7.1%). The EOs obtained from targeted samples exhibited strong α-glucosidase inhibitory activity. These results are encouraging and underline that the EOs of Eucalyptus species may be a promising alternative source of natural antidiabetic.