Chemistry, Functional Groups

Question 1

Volatile compounds in EOs are classified by:

Answer 1

Shape

• Aliphatics - essentially linear (can loop & appear ring like) based on a 5 Carbon structure - Isoprene Unit
• Aromatics - 6 Carbon ring structure

Chemicals they contain

• Terpenes - Hydrogen & Carbon only = Hydrocarbons
• Oxygenated compounds - Hydrogen, Carbon & Oxygen

Question 2

What are functional groups?

Answer 2

Chemicals can be divided into groups which have similar actions, either because of
- their chemical components or
- the way the molecules are arranged
These are known as functional groups

Question 3

TERPENES
Monoterpenes
Sesquiterpenes
Diterpenes

Answer 3

Names ending in ‘ene’
Isoprene unit 5C, 8H

Monoterpenes - 2x isoprene units 10C, 16H. Common.
General action slightly antiseptic & antibacterial.
Some quench more aggressive effects of other chemicals.

Sesquiterpenes - 3x isoprene unit 15C, 24H, Less common.
In addition to terpen actions above - generally anti-inflammatory & calming, slightly hypotensive, analgesic & antispasmodic.

Diterpenes - 4 x isoprene units 20C, 32H - rare as molecules too heavy to be volatile.
Generally expectorant, some antifungal, antiviral & hormone balancers.

Question 4

ALCOHOLS

Answer 4

End in ‘ol’ (phenols also end in ‘ol’ - group with cautions!)
Generally non toxic, non irritant.
Strongly antibacterial, antiviral, anti-infectious.
Stimulating if monoterpene based eg linalol
Sedating if sesquiterpene based eg santalol

Question 5

ESTERS

Answer 5

End in ‘yl’, ‘ate’ eg Linalyl acetate

Generally non toxic, non irritant
Antifungal, anti-inflammatory, antispasmodic, cicatrisant.
Calming to the nervous system.

Question 6

ALDEHYDES

Answer 6

End in ‘al’ or aldehyde eg CITRAL

Potential skin irritants

General antiviral, anti-inflammatory, antipyretic.
Calming to nervous system, hypotensive, vasodilators

Question 7

PHENOLS

Answer 7

End in ‘ol’ (as do alcohols)

• Potential skin irritants*
• potential liver toxicity*

Generally stronger antiseptic, antibacterial
Stimulants of nervous & immune systems

Question 8

PHENOLIC ETHERS

Answer 8

Often end in ‘ole’

Similar to phenols but additionally

• Potential neurotoxic agents*
• potential carcinogens*

Question 9

KETONES

Answer 9

Often end in ‘one’

• Generally caution needed/avoid in pregnancy*
• Potentially neurotoxic*

Generally mucolytic, expectorant
Some are analgesic, digestive

Question 10

OXIDES

Answer 10

Ending is variable - ‘ol’, ‘ole’, oxide

Potentially skin irritant

Generally expectorant & mucolytic

Question 11

LACTONES

Answer 11

Potential problems with phototoxicity & skin sensitivity

Generally mucolytic, expectorant, temperature reducing