Objective: The scavenging effects of 8 extracts from several plants used as both medicines and foods on oxygen free radicals were studied in vitro.
Methods: Chemiluminescence (CL) method and ultra-weak luminescence technique were used, meanwhile, macrophage respiratiory burst was also carried out to evaluate the antioxidation reaction.
Results: The scavenging activity on superoxide anions (O2-.) differed in the following order: extract of clove (CE) > black tea (BTE) > green tea(GTE) > grape peel/seed (GE) > or = oologn tea (OTE) > > tumeric (TE). In Fenton reaction for hydroxyl radicals (.OH), the order as follows: BTE > CE > or = GTE > GE > OTE > > TE. Most extracts have stronger eliminating efficiency on .OH than on O2-. except CE, which may scavenge the O2-. formation more efficiently. After macrophages (5 x 10(6) cells/ml) were stimulated with phorbol myristate acetate, BTE showed stronger inhibiting action than CE on respiratory burst in macrophages. The results of ultra-weak luminescence measurement indicated that the extracts could delay and depress the DNA damage in CuSO4-Phen-Vc-H2O2-DNA chemiluminescence system.
Conclusions: It suggests that the tested antioxidants could decrase the formation of O2-. or .OH, some have chain-breaking function and preventative function during DNA damage.