FRAGRANCE AND SKIN CARE Flashcards
WHERE CAN ESSENTIAL OILS B EXTRACTED
from plants
concentrated extracts of the aroma compounds from plants that are not water-soluble
essential compound of essential oils
terpenes
Terpenes
unsaturated hydrocarbons, formed by joining together units of 2-methylbuta-1,3-diene. this molecule is known as isoprene
units that make up terpenes
isoprene
Isoprene structural form
2-methylbut-1,3-diene
C5H8
Isoprene to terpene
added together head to tail to form terpenes
both long straight chain and cyclic molecules can be formed
terpene oxidised
after being oxidised within plants, terpenes are responsible for the flavours of many distinct spices such as ginger, cloves and cinnamon
terpene oxidised examples
Vannilin
Limonene
Cinnamaldehyde
Thymol
Citronellal
Cittronellol
UV from sun
high energy form of light
Increasing types of UV radiation
UVA
UVB
UVC
UV does what to skin
break down collagen, which can lead to premature ageing
Block UV
Sunblock by preventing UV being absorbed
Over exposure to UVB
Sunburn, skin cancer
UVA and skin cancer
Indirectly breaking down DNA in a process that involves free radicals
Free radicals
highly reactive atoms that have on unpaired electron
why are free radicals unstable
tendency for unpaired electrons to pair up and so free radicals react quickly
How are radicals formed
covalent bond is broken by energy supplied by UV light. Due to their reactivity, they can cause chain reactions, as they often react to produce other free radicals. 3 stage process
Stage 1 free radical formation
Initiation
Dot next to each Br indicated one unpaired electron each has from shared pair electrns of covalent bond. Dividing one BR molecule produces 2 highly reactive radicals.
When UV light is needed to begin the process, further reactions do not need UV light, and so chain can continue in darkness
Stage 2 free radicals
Propagation
Highly reactive radicals formed can remove atoms from other stable compounds to re-establish stable covalent bonds. This reaction produces a new free radical.
The new radical can inturn react with another Br molecule. This is also known as propagation step as generates a radical; product
Stage 3 radical formation
termination
chain reaction will only end when a reaction takes place in which no new radicals are formed. this can occur whenever free radicals react with each other
free radical scavangers
chemicals (usually vitamins, minerals or enzymes) that react and destroy free radicals
desirable to protect our skin and our food
where are free radical scavangers found
cosmetics and in some foods and plastics
free radical and radical scavanger react
prevent chain reaction occuring
many free radical scavangers are
antioxidants
green tea scavanger
polyphenols
