Pharmacognostical, Antioxidative Activity Associated with Phytochemical of Eucalyptus globulus Labill. and Evaluation of in vitro Antidiabetic Potential

Eucalyptus globulus Labill. is an traditionally used medicinal plant for many ailments. The study was planned to examine the pharmacognostical, phytochemical and evaluation of in vitro potential of the methanolic extract of the species. Pharmacognostical and phytochemical evaluation was performed as per the standard protocol of the API. Quantification of bioactive compounds was done by the developed HPTLC method using mobile-phase toluene/ethyl acetate/formic acid (7:3:0.5). The pharmacological potential of the species was also evaluated by in vitro antioxidant and antidiabetic inhibition of the methanolic extract. In antioxidant inhibition, two methods, i.e., ABTS and DPPH assays, were used for the evaluation of the antioxidant potential; additionally, α- glucosidase and α-amylase were used for E. globulus extract. In ABTS, fruit extract exhibited the highest % inhibition (0.0187 ± 0.01) (≤ IC50 values) and bark extract exhibited lowest % inhibition (0.00014 ± 0.02) with the highest antioxidant potential. Similarly, in the DPPH scavenging method, the fruit extract exhibited the highest % inhibition (0.127 ± 0.02) and stem bark extract exhibited lowest % inhibition (0.057 ± 0.01) with the highest antioxidant potential. In α-glucosidase, lowest IC50 value was found on leaves parts (1.11 ± 0.005) µg/ml and alpha-amylase lowest IC50 were recorded on fruit part (1.18 ± 0.01) having the highest inhibition. Therefore, we can conclude that identified marker compounds play a crucial role in the potential of antidiabetic as well as antioxidant activity of the species. This study will be helpful in the future for the standardization, quality control and antidiabetic drug formulation containing this species as an ingredient.