Carotenoids—Antioxidant Properties

Carotenoids—Antioxidant Properties

Author Name : Dr. Sudhir Kumar Mishra

ABSTRACT

The carotenoid group of pigments are ubiquitous in nature and more than 600 different carotenoids have been identified and characterized ¹. They are responsible for pigmentation in animals, plants, and microorganisms, but crucially also serve important, often critical, roles in biological systems. Indeed, in recent years most attention focused on this group of pigments has concerned understanding their function, especially as antioxidants. The “core” structural element of carotenoids is a polyene backbone consisting of a series of conjugated C=C bonds. This particular feature is primarily responsible for both their pigmenting properties and the ability of many of these compounds to interact with free radicals and singlet oxygen and therefore act as effective antioxidants. Modifications to this polyene backbone, altering the number of conjugated double bonds together with the addition of oxygen functional groups, in turn, alter the reactivity of carotenoids. Importantly, the function of carotenoids is also substantially affected by their immediate environment, which, in turn, is dependent on their structure. This is arguably most evident in photosynthetic systems in higher plants and algae where xanthophylls are restricted to light-harvesting complexes (performing both light-capture and photoprotective roles), whilst β-carotene is found in reaction centers (a protective role).