skincare Flashcards
exposure to UV light can result in …
molecules in the skin gaining sufficient energy for bonds to break
sun block products …
prevent UV light reaching the skin
UV light can lead to …
sunburn and extended exposure can also cause ongoing skin aging and ultimately skin cancer
why does UV cause premature ageing
affects the collagen in our skin
Free radicals are …
highly reactive atoms that have one unpaired electron
highly reactive species with unpaired electrons
Free radicals are unstable as …
there is a tendency for unpaired electrons to pair up and so the free radicals react very quickly
Radicals can be formed when …
a covalent bond is broken by energy supplied by UV light
The chain reaction of free radicals is threefold:
Initiation
Propagation
Termination
Initiation:
produces free radicals
propagation:
Free radicals form other free radicals
Termination:
Free radicals are removed from the system
Free radical scavengers are …
chemicals (usually vitamins, minerals or enzymes) that react with and destroy free radicals.
Free radical scavengers are often desirable to
This is often desirable to help protect our skin (so they are present in cosmetics) and our food (present both in some foods and in plastics).
By reacting with any free radicals present, the free radical scavengers
prevent a chain reaction from occurring.
Many free radical scavengers are
antioxidants
what happens when polyphenols react with free radical scavengers
further reactions are prevented.
Green tea as an example of radical scavengers
For example, green tea contains polyphenols which act as free radical scavengers. These react quickly with two of the most common radicals, hydroxyl radicals ( O- ) and oxygen radicals (HO-), formed from the breakdown of water and oxygen respectively. When polyphenols react with these radicals, further reactions are prevented.
Antioxidants are a type of
free radical scavengers
