Comparative study on the antioxidant activities of extracts of Coreopsis tinctoria flowering tops from Kunlun Mountains, Xinjiang, north-western China

Abstract

Coreopsis tinctoria flowering tops (CTFs) from the Kunlun Mountains in Xinjing (north-western China) have been used for tea production for about a century. This study aims to assess the antioxidant activities and total phenolic, flavonoid and proanthocyanidin contents of various solvent extracts of CTF. CTF was extracted using n-hexane, chloroform, ethyl acetate, n-butanol, 75% aqueous ethanol (AEE) and water. The antioxidant activities of the CTF extracts were investigated through DPPH, ABTS, ^*OH, ^*O₂⁻ , total antioxidant capacity and reducing power assays. The results showed that n-butanol extract showed the highest contents of total phenols and flavonoids, with DPPH, ABTS and ^*OH radical-scavenging activities with IC₅₀ values of 134, 90.72 and 13.8 μg mL^− 1, respectively. The AEE demonstrated the strongest DPPH and ABTS radical-scavenging activities, with IC₅₀ values of 103 and 75.16 μg mL^− 1, respectively. Given its high antioxidant effect, CTF is a good source of natural antioxidants or functional food materials.

Keywords:

• antioxidant activity
• Coreopsis tinctoria Nutt
• radical scavenging activity

Additional information

Funding

This study was supported by the Key areas of the science and technology research projects in Xinjiang Production and Construction Corps [grant number 2014BA031] and through the high-level talents of the scientific research foundation of Shihezi University [grant number RCZX201328].