Antioxidant Synergy with carotenoids

1. AntioxidantSynergy withcarotenoids Brindajoshi Date: 04/17/2014

2. Carotenoid • natural pigments • more than 600 carotenoids • α- carotene, β-carotene, lutein, lycopene. • lycopene – Most effective. 30% to total carotenoids in humans.

3. The chemical and biological function of carotenoids is determined by their characteristic structure Major role: • protection of plants against photooxidative processes and Act as a effective antioxidant • In human body, it’s a part of antioxidant defense system • Carotenoids prevents the risk of cardiovascular disease, cancer, coronary artery disease. It also protect the skin against photooxidative damage.

4. Structure • derived from a 40-carbon basal structure having system of conjugated double bonds • lipophilic molecules

5. Antioxidant activity • Antioxidants scavenge radicals • by reacting with them to yield stable and harmless product • by disrupting free radical chain reactions • The system of conjugated double bonds allows lycopene molecules to efficiently quench the energy from singlet oxygen and to scavenge a large spectrum of free radicals.

7. Pro-oxidantactivity • If concentration of lycopene is high, • Antioxidant activity decreases • Act as a prooxidant • can be converted into peroxyl

8. Degradation pathway of lycopene

9. Oxidative DNA damage caused by xanthineoxidase • Protected by low concentration of lycopene • Increases by high concentration of lycopene • Oxidation of lipid • At low oxygen concentration, carotenoids act as effective antioxidants • At high oxygen concentration, carotenoids enhance the oxidation of lipid.

10. Role of antioxidants in Synergestic effect

11. Factors affecting antioxidant synergy • Temperature • substrate • pH • Type and combination of antioxidants • Type of oxidants involved • Ability to quench singlet oxygen and to trap peroxyl radicals. • Concentration of antioxidant

12. Mechanism in synergic effect • Sparing Mechanism: • when two antioxidant working by the same or different mechanism at the same time. • when both are working by different mechanism, gives significant synergistic effect. For example: tocopherol- as a peroxy radical scavengers. β- carotenoid- as singlet oxygen quencher.

13. 2) Regenerating mechanism: When two antioxidants are present together and one of them is capable of regeneration of other from radicals or oxidation products. For example: vitamin C can regenerate carotenoids from its radical and enhance effect. But “side effects” of antioxidants have to considered. Vitamin C is a strong reductant for trace metal ions and can shows prooxidant effects in many cases.

14. 3) Trace metal chelation: Tocopherol shows synergistic effects with phospholipids which have metal chelating properties. For example: Maillard reaction products produced by reaction of reducing sugars with amino acids were good inhibitors of linoleic acid oxidation, and acted as synergists with tocopherol.

15. Conclusion • When more than a single antioxidant is present in an oxidizing lipid system, their net antioxidant effect is more than the sum of their individual effects. • The concentration and combination ratio of mixed antioxidants are the important factors. • Lipophilic and hydrophilic properties of antioxidants and free radicals are important factors. • 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.

16. References: • John shi and Qin Qu, Yukio Kakuda, David Yeung, Yueming Jiang. Stability and synergistic effect of antioxidative properties of lycopene and other active components. • Wilhelm Stahl, Helmut sies. Antioxidant activity of carotenoids. • Donghong Liu, John Shi, Yukio Kakuda, Sophia junXue, (2007). The scavenging capacity and synergistic effects of lycopene, vitamin E, vitamin C and β-carotene mixtures. • Fritz Bohm, Ruth edge, Edward land, georgetruscott (2010). Carotenoids enhance vitamin E antioxidant activity.