There are many factors that might contribute to SEs of
mixed antioxidants in a biological system. The concentration
and combination ratio of mixed antioxidants are the
important factors. It has been shown that specific
concentrations and combinations of antioxidants in
mixtures were more effective than the corresponding single
antioxidants in the scavenging of DPPH. In this study a
significant SE was produced only when lycopene was
present in a mixture. For the mixtures of two-antioxidants,
lycopene with vitamin E, lycopene with vitamin C, and
lycopene with b-carotene, showed SEs. For the mixtures of
three-antioxidants only the lycopene+vitamin E+vitamin
C showed synergism. For four-antioxidants, the following
combination, e.g. a mixture of lycopene (15.63 mmol/L),
vitamin E (5.0 mmol/L), vitamin C (0.16 mmol/L), and bcarotene
(10.83 mmol/L), produced an SE of 1.34. The
synergistic effect appears to be based in part on the
reducing potential of the various antioxidants and their
ability to convert the antioxidant free radicals to their
native form. The results indicate that an optimum
combination of antioxidants may play a significant role
in enhancement of the oxidative status of biological
systems.