|
|
|
ZeaLuteinâ : Synergistic effects of the component carotenoids
 |
The
mixture of carotenoids present in the composition provides synergistic effects. This was
validated in a study that compared the antioxidant effects of single and mixed
carotenoids.
|
|
Mixtures
of carotenoids were found to be more effective than the single compounds.
|
|
This
synergistic effect was most pronounced when lycopene or lutein was present.
|
|
The
authors of this study suggest that the superior protection of mixtures may be related to
specific positioning of different carotenoids in membranes in the cells.
|
|
The antioxidant activity of carotenoids in
multilamellar liposomes was assayed by determining the inhibition of formation of
thiobarbituric acid-reactive substances (TBARS). The antioxidant activity of various
individual carotenoids was ranked as: lycopene> alpha-tocopherol > alpha-carotene
> beta-cryptoxanthin > zeaxanthin = beta-carotene > lutein (Figure 1).
|
Figure 1: TBARS formation in multilammelar liposomes in the
presence of single antioxidants (3 mM)
The
composition of the mixtures of carotenoids tested is shown in Table 1:
Table 1:
Contributions of single compounds to carotenoid mixtures (mM)
| Code |
Lycopene |
a-Carotene |
b-Carotene |
b-Cryptoxanthin |
Zeaxanthin |
Lutein |
a-tocopherol |
| M1 |
0.66 |
0.33 |
0.66 |
0.33 |
0.33 |
0.66 |
- |
| M2 |
- |
0.43 |
0.86 |
0.43 |
0.43 |
0.86 |
- |
| M3 |
0.86 |
0.43 |
0.86 |
0.43 |
0.43 |
- |
- |
| M4 |
- |
0.60 |
1.20 |
0.60 |
0.60 |
- |
- |
| M5 |
1.20 |
0.60 |
- |
0.60 |
0.60 |
- |
- |
| M6 |
0.07 |
0.03 |
0.07 |
0.03 |
0.03 |
0.07 |
2.70 |
| M7 |
1.50 |
- |
1.50 |
- |
- |
- |
- |
| M8 |
2.00 |
1.00 |
- |
- |
- |
- |
- |
| M9 |
2.00 |
- |
- |
1.00 |
- |
- |
- |
| M10 |
1.50 |
- |
- |
- |
- |
1.50 |
- |
| M11 |
2.00 |
- |
- |
- |
1.00 |
- |
- |
| M12 |
- |
- |
1.00 |
- |
- |
2.00 |
- |
| M13 |
- |
1.00 |
2.00 |
- |
- |
- |
- |
|
Final
concentration in each mixture is 3 mM.
Figure 2: TBARS formation
in multilamellar liposomes in the presence of antioxidant mixtures (3 mM)
M1: Complete carotenoid mixture
M2: M1 minus lycopene
M3: M1 minus lutein
M4: M1 minus lycopene minus lutein
M5: M1 minus lutein minus beta-carotene
M6: M1 plus tocopherol
|
The data obtained for mixtures of various carotenoids
is shown in Figures 2 and 3. Based on the data obtained for single components as shown in
Figure 1 and normalized for their molar contribution to M1, the theoretical inhibitory
value was calculated for each combination.
|
|
A significant difference between the theoretical and
measured values indicates synergistic effect as observed in combinations containing lutein
and/or lycopene.
|
Calculated value = |
å (exp
value(%) x molarity [micro mol] |
|
| 3(micro mol) |
|
|
The
data obtained in this in vitro study reveal that combinations of carotenoids are
more effective than single compounds in preventing oxidative damage. Mixtures of
carotenoids exhibited more than an additive antioxidant effect when lycopene and/or lutein
were included, suggesting synergistic action.
|
|
The
authors of this study suggest that the superior protection of mixtures may be related to
specific positioning of different carotenoids in membranes and the physicochemical
properties of the compounds.
|
|
Xanthophylls
such as zeaxanthin and violaxanthin span the membrane, with the polar endgroups anchored
at polar sites of the membrane. As beta-Carotene and lycopene do not have hydrophilic
substituents, they remain entirely within the inner part of the membrane and retain
mobility. The authors concluded that specific orientations of carotenoids might provide
shielding effects that account for synergistic properties of the carotenoids.
|
Figure 3: TBARS formation in
multilamellar liposomes in the presence two-component antioxidant mixtures (3 mM)
M7: Lycopene+beta-carotene
M8: Lycopene+ alpha-carotene
M9: Lycopene+beta-cryptoxanthin
M10: Lycopene plus lutein
M11: Lycopene plus zeaxanthin
M12: Lutein plus beta-carotene
M13: beta-carotene plus alpha-carotene
Reference
1. Stahl, W., Junghans, A., de Boer, B., Driomina, E.S., Briviba, K., Sies,
H. (1998) Carotenoid mixtures protect multilamellar liposomes against oxidative damage:
synergistic effects of lycopene and lutein. FEBS Letters, 427, 305-308.
© Sabinsa Corporation 2000 |
