Mee-Ree Kim

Antioxidant Activities of Rehmannia glutinosa by Traditional Methods

The objective of this study was to evaluate antioxidant activities of Rehmannia glutinosa (Raw Jihwang) by traditional method. The total phenol content of Rehmannia radix Preparata (the final cycle of Jihwang) was increased to 205%, compared with Rehmannia glutinosa. Antioxidant activities, determined by ferric-reducing antioxidant potential (FRAP), 2,2`-azinobis(3 ethybenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity, 1,1-diphenyl-2-picrydrazyl (DPPH) and hydroxyl radical scavenging activities, increased remarkably as the number of steaming-drying cycles increased. Especially, FRAP value increased 285%. Also, values for DPPH and hydroxyl radical scavenging activities of the final 9th-cycling product, decreased 48.4% and 76%, respectively, compared with those of Rehmannia glutinosa. Our result was suggested that antioxidant activities of Rehmannia radix Preparata improve according to the increasing number of steaming-drying cycles.