Antioxidant synergism between ethanolic Centella asiatica extracts and α-tocopherol in model systems

Yin Yin Thoo, Faridah Abas, Oi Ming Lai, Chun Wai Ho, Jie Yin, Rikke V. Hedegaard, Leif H. Skibsted, Chin Ping Tan

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The synergistic antioxidant effects of ethanolic extracts of Centella asiatica (CE), and α-tocopherol have been studied. The types of interactions exhibited by CE and α-tocopherol combined at different ratios were measured using three assays: 2,2′-azino-bis(3-ethylbenzothiazoline- 6-sulphonic acid) diammonium salt (ABTS) radical-scavenging capacity, the β-carotene bleaching system and liposome peroxidation assays. Fixed-fraction isobolographic analysis was used to detect any inducement of the antioxidant activity compared with the individual activities of CE and α-tocopherol. Of all synergistic combinations of CE and α-tocopherol, only fraction 2/3 showed the synergistic combination that fits well in three different assays and can be explained by the regeneration of α-tocopherol by CE despite the interaction effect of β-carotene present in the analytical assay. This phenomenon involved complex interactions between CE and α-tocopherol to exhibit different degrees of interactions that eventually increased antioxidant activity.

Original languageEnglish
Pages (from-to)1215-1219
Number of pages5
JournalFood Chemistry
Issue number2-3
Publication statusPublished - 1 Jun 2013
Externally publishedYes


  • α-Tocopherol
  • Isobolographic analysis
  • Synergism
  • Ultrasound

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