Effect of different drying methods on the antioxidant properties of leaves of Centella asiatica

Abstract

Centella asiatica is one of the vital plant sources of antioxidants properties for consumption or medicinal purposes. This study aimed to determine the effect of three different drying methods (freeze drying, oven drying and dehydration drying) on the antioxidant of leaves of C. asiatica. The antioxidant properties and IC50value of different concentration of methanolic extract solution (0.5 mg/ml, 0.25 mg/ml, 0.125 mg/ml and 0.062 mg/ml), were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The drying conditions and time required for freeze drying, oven drying and dehydration drying were -45°C for 3 days, 60°C for 5 hours and 35-43°C within 1-3 hours, respectively. Samples with lower IC50value showed a stronger antioxidant activity since low IC50determine the efec. The freeze-dried of C. asiatica sample at 0.05 mg/ml concentration exhibited the highest scavenging activity (93.97 ± 0.45%) with the lowest IC50value (0.05 mg/ml) whereas the lowest scavenging activity was shown by dehydration dried of C. asiatica sample at 0.05 mg/ml concentration (55.08 ± 0.03%) with the highest IC50value (0.36 mg/ml). This indicates that as the concentration increases, the radical scavenging activity increases. Thus, it is highly recommended to use freeze drying as the method to conserve the maximum amount of antioxidant properties in C. asiatica leaves.