Background : The objective of this study was to determine the antioxidant activities of safflower (Carthamus tinctorius L.) seed extracts using various solvents.
Method and Results : The safflower seed extracts was obtained using methanol (50, 75, 100%), ethanol (50, 75, 100%) and water. Total phenolic content (TPC) w as determined by Folin-Ciocalteu method and antioxidant activities w ere estimated by 2,2-diphenyl-1-picryl-hydrazil (DPPH), 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS) radical scavenging activities, ferric reducing antioxidant power (FRAP) and reducing power (RP). Average TPC of safflower seed extracts were 72.03 ㎍·GAE·㎎-1 DE in methanol, 50.16 ㎍·GAE·㎎-1 DE in ethanol, and 28.47 ㎍·GAE·㎎-1 DE in water. TPC were significantly different (p < 0.05) between the solvents. DPPH, ABTS, FRAP and RP a average activities of methanol extracts showed the highest antioxidant activity, with value of 62.95 ㎍·ASC·eq/㎎ DE, 123.48 ㎍·ASC·eq/㎎ DE, 171.68 ㎍·ASC·eq/㎎ DE, and 76.07 ㎍·ASC·eq/㎎ DE, respectively. Values of Ethanol extracts showed DPPH 32.26 ㎍·ASC·eq/㎎ DE, ABTS 81.02 ㎍·ASC·eq/㎎ DE, FRAP 159.24 ㎍·ASC·eq/㎎ DE, and RP 34.83 ㎍·ASC·eq/㎎ DE. There was no significant difference between extracts of ethanol and methanol in FRAP value. The 75% ethanol extracts showed higher antioxidant activity than 50% and 100% ethanol extracts (p < 0.05). The 75% ethanol extracts had TPC 68.98 ㎍·GAE·eq/㎎ DE, DPPH 70.07 ㎍·ASC·eq/㎎ DE, ABTS 166.59 ㎍·ASC·eq/㎎ DE, FRAP 208.78 ㎍·ASC·eq/㎎ DE, and RP 82.16 ㎍·ASC·eq/㎎ DE.
Conclusion : Although ethanol extracts had lower antioxidant activity compared to methanol, it was suggested to be more suitable for further studies as it is less toxic and a recommended food grade solvent. It is estimated that the bioactive substance is extracted extensively from 75% ethanol with high antioxidant activity.