Abstract: Objective: To explore the in vitro antioxidant activities of different solvent extracts from the root tubers of C. wenyujin. Methods: The root tubers of C. wenyujin were extracted with solvents of different polarity, such as distilled water, 95% ethanol and ethyl acetate, respectively. The resulting extracts were assessed for antioxidant properties, such as DPPH free radical scavenging activity, hydroxyl free radical scavenging activity, ferrous ion-chelating capacity and reducing power. Meanwhile, the total phenol contents of the extracts were determined by the Folin-Ciocaile method and the correlation between total phenol content and antioxidant properties was analyzed. Results: The 95% ethanol and ethyl acetate extracts showed high free radical scavenging activity at low concentrations and had higher total phenol content than the distilled water extract. Therefore, the powerful antioxidant activity of the 95% ethanol and ethyl acetate extracts is immediately linked to their higher total phenol content. However, their ferrous ion-chelating capacity was inferior to that of the distilled water extract. Conclusions: The different solvent extracts from the root tubers of C. wenyujin show a considerable difference in their antioxidant activities and a correlation between their total phenol content and antioxidant properties.

Key words: Curcuma wenyujin, DPPH free radical, hydroxyl radicals, ferrous ion-chelating capacity, reducing power, Folin-Cioeaile method