In vitro antioxidant potential of Rhododendron arboreum leaf extracts

The study was carried out to evaluate the in vitro antioxidant potential of hydroethanolic and hydromethanolic extract of Rhododendron arboreum. Hydroethanolic extract showed 90.55% and hydromethanolic extract 84.14% DPPH scavenging activity at 250μg/ml concentrations, respectively. The IC₅₀ values of hydroethanolic and hydromethanolic extracts were 65.47μg/ml and 65.40 μg/ml, respectively. ABTS scavenging activity of R. arboreum showed a significant (P< 0.05) increase in antioxidant activity viz., 83.61 % whereas hydromethanolic extract showed 78.41% at 250 μg/ml. The IC₅₀ values of hydroethanolic and hydromethanolic extracts were 70.81 μg/ml, 70.94μg/ml, respectively. On assay of nitric oxide synthetase activity, the maximum activity was observed in hydroethanolic extract followed by hydromethanolic extracts of Rhododendron arboreum viz., 81.22% and 77.28%, respectively, at 500 μg/ml. The I_C50 values for hydroethanolic and hydromethanolic extracts of Rhododendron arboreum were 144.13 μg/ml and 154.34 μg/ml, respectively, which showed potent antioxidant potential. Thus, both the extract showed potent antioxidant potential, however, hydroethanolic extract showed more potent antioxidant activity than hydromethanolic extract.