Terpenes, Volatile oils and other compunds Flashcards
Volatile oils also referred to as
ethereal’ and ‘essential oils
___________will evaporate into the atmosphere if left exposed.
volatile oils (cf. Fixed oils)
State the characteristics of essential oils /Volatile oils
They are generally complex mixtures
Have an associated smell (useful for identification)
Are often optically active
Have a high refractive index
Not very soluble in water but soluble in organic solvents,
They are prone to oxidation (colour change).
List types of compounds present in Volatile oils
Terpenoids(mainly monoterpenes)
Phenylpropane compounds,
Simple alcohols (methanol, ethanol)
and occasionally any one of the major compounds as a glycoside (linkage to a sugar)
_____________form one of the largest groups of compounds, occurring in plants, animals and insects, and many other organisms.
Terpenoids
Functions of Terpenoids are still not realised for most of the compounds
____________have hormonal function
_________ have antioxidant function
__________ possess antibacterial and antifungal activity
some ___________ occurring in plants have deterrent properties
Sterols
Carotenoids
Sesquiterpenes
terpenes
What are terpenes?
and isoprene units are made of?
These are composed of isoprene units (derived from acetylCoA molecules) condensed together under enzymatic control.
An isoprene unit is a branched five-carbon unit (C5H8).
Mention the four(4) main groups of Terpenoids
Monoterpenes
Sesquiterpenes
Diterpenes
Triterpenes
A compound that contains two isoprene units is known as
Monoterpenes C10H16
A compound composed of three(3) isoprene units
Sesquiterpenes (C15H24)
A compound composed of four(4) isoprene units
Diterpenes (C20H32)
A compound composed of six(6) isoprene units is called
Triterpenes
List the different types of reaction that increase the range of terpenoids compound
N/B: _____________present will influence the compounds that will exist in plant
Cyclization and Oxidation reactions
N/B: The type of reaction present will influence the compounds that will exist in plant
The structure of monoterpenes found in volatile oils may be ______________
linear, monocyclic, or bicyclic.
Facts about Geraniol ( hint it is present in 7 things) (has 3 agents)
Geraniol is ___________
Geraniol is an important constituent of essential oil of ginger, lemon, lime, lavender, nutmeg, orange and rose. It has been reported to have cytoprotective, antioxidative and anti-carcinogenic agent.
Geraniol is an example of Linear Monoterpenes
Eucalyptus oil is a volatile oil used for……..
Inhalation/decongestion
What is the therapeautic use of Peppermint?
Carminative
What is the therapeautic use of Begarmot/Cinnamon?
Flavouring
What is the therapeutic use of Clove?
Tooth Tincture/Antiseptic
What is winter green used for ?
Analgesic
What is Rose/Lavender used for
Perfumery/Cosmetics
What are Phenylproprane compounds?
Nine(9) carbon-based compounds that have an aromatic ring
The biosynthesis of Phenylproprane compounds is from ……….
Shikimic acid
State the two main methods of extracting oil from it plant source
- Distillation(Two main types of distillation processes are used.)
- Water distillation – Boiling the plant material in water. The water vapour and the oil condense separately. The oil forms a layer on the water and is then collected. Cannot be used for oils that decompose easily.
- Steam distillation – The plant material, suspended in a basket, is treated with steam. The oil is recovered at a lower temperature (< 100 oC) than its boiling point (usually in excess of 200 oC) by this method. Can only be used where significant amounts of oil are present and if the oil is not easily oxidised/hydrolysed. (See handout on Moodle for diagram of apparatus and collecting vessels for oils lighter and heavier than water.)
(Note: Some oils are glycosides and these need to be hydrolysed [enzymatically or using mineral acid] before under taking distillation.)
- Expression (Pressure): This is a process by which oils are obtained by applying pressure (e.g. lemon oil BP). Machines called ‘sfumatrice machines’ are available but the quality of the oil is inferior to that produced by the ‘hand method’. With the latter method there is very little contact with the albedo layer, which contains enzymes that can degrade the oil.
What does rectification of oils mean?
It is the purification of oil after recovery by a second distillation.
List two examples of oil Rectified?
Turpentine and Caraway
State the physical properties of volatile oil?
mention 8
how should it be stored?
Most are optically active (evaluation.
e.g.___________ is (−); synthetic is a racemic mixture ___________ is (+); synthetic is a racemic mixture
1 . Usually colorless when freshly prepared, but tend to oxidize and darken in color on standing. Store in a cool dry place, tightly stoppered, amber glass container and kept full if possible.
- Insoluble in water, but sufficiently soluble to impart an aromatic odor to water (aromatic waters).
- Soluble in most common organic solvents e.g. ethanol, CHCl3, and ether.
- Usually lighter than water; exceptions are clove and cinnamon oils.
- Have characteristic odors (evaluation).
- Have high refractive indices (evaluation).
- Most are optically active (evaluation.
e. g. natural menthol is (−); synthetic is a racemic mixture natural camphor is (+); synthetic is a racemic mixture - Do not leave a permanent translucent stain on the paper.
Peppermint oil BP is obtained from ………………….
the dried leaves and flowering parts of
Menthae piperitae.
Know the following about Peppermint Oil
The plant is cultivated and contains ___________ by dry weight.
The oil is isolated by ______________
__________is composed of menthol and the rest is made up by __________________
Quality of the oil is influenced by ___________. Good quality
oil needs______________. Younger plants
contain predominantly a compound called ______________. The oil is characterized by _____________
Menthol has been credited with a pharmacological basis, it activates the ____________; cold and menthol receptor 1; CMR1) which than causes depolarization of sensory nerves resulting in an _______________________
The plant is cultivated and contains 1 % volatile oil by dry weight.
The oil is isolated by steam distillation.
50% of the oil is composed of menthol and the rest is made up by acetate of menthol, menthone, and other monoterpenes.
Quality of the oil is influenced by the age of the plant and seasonal variation. Good quality
oil needs a large proportion of esters and ketones (menthone and Jasmone). Younger plants
contain predominantly a compound called (+)-pulegone. The oil is characterized by gas
chromatography in the BP.
Menthol has been credited with a pharmacological basis, it activates the TRPM8 receptor (Transient receptor potential cation channel subfamily M member 8; cold and menthol receptor 1; CMR1) which than causes depolarization of sensory nerves resulting in an antitussive effect, mild anesthesia, and a cool feeling.
State the uses of Peppermint Oil
the oil is used as a flavoring and finds considerable use in confectionary
Clinical uses include as a carminative in antacid preparations (e.g. Gelusil and Bisodol),
and also recommended for controlling symptoms of IBS.
Eucalyptus oil is obtained from?
by steam distillation of the fresh leaves of Eucalyptus globulus
Eucalyptus oil is often rectified and contains more than _____________
Identification test for the oil is based on a _____________
70% cineole (eucalyptol).
TLC method.
State the Uses of Eucalyptus Oil
In inhalations and lozenges as a decongestant.
The oil is antiseptic and an insect repellent
The main monoterpenes found in Tea tree oil is known as?
It has been shown to have activity against______________
(including _______) and as well as yeasts such as _________-. Other compounds that have been shown to have similar activity and are also present in the oil are _________, ___________ and _____________.
Terpinen-4-ol.
It has been shown to have activity against a number of bacterial species
(including Gram-negative) and as well as yeasts such as Candida albicans. Other compounds that have been shown to have similar activity and are also present in the oil are α-terpinenol, γ- terpinene and linalool.
State the Uses of Tea tree Oil
hint 6 in number
formulated in many types of preparations for acne, sore throat, thrush, scabies, lice, and skin infections.
Clove oil is obtained from?
The flower buds contain_______________
how is it extracted?
the dried flower buds of Syzygium aromaticum. The flower buds contain 14-20 % volatile oil (steam distillation).
The main compound found in Clove oil is …….
Eugenol (90 %).
Eugenol (4-allyl-2-methoxyphenol) is a phenylpropane derivative.
An example of an irregular Monoterpenes is called?
Valerian (Valeriana officinalis)
Facts about Irregular Monoterpenes (Iridods)
___________of the valerian plant has traditionally been used for __________ and for ________________. It contains a number of closely
related structures to _______.
Concentrate on the ___________leaving out the___________ = iridane ring system which is an irregular monoterpene. See Slide 15
These compounds are thought to be responsible for ___________.
Some studies have shown that extracts of the plant do have ________ and can help ___________. However, evidence is required to be backed by clinical trials.
Root of the valerian plant has traditionally been used for anxiety type conditions (sedative) and for insomnia. It contains a number of closely
related structures to valtrate.
Concentrate on the middle ring structure leaving out the ester groups = iridane ring system which is an irregular monoterpene. See Slide 15
These compounds are thought to be responsible for the biological activity.
Some studies have shown that extracts of the plant do have a calming effect and can help short term insomnia. However, evidence is required to be backed by clinical trials.
List other examples of volatile oils
Fennel, dill, cinnamon, and aniseed (carminative), citronella (insect repellent), juniper and pine (antiseptic), and turpentine (chemically converted to many other compounds).
Uses of clove oil
has analgesic/antiseptic properties and is used as a tooth tincture. Purified eugenol is synthetically converted to vanillin (compare structures). The antiseptic properties has inclined it to be used in dentistry as a component of a cement containing zinc oxide for temporary sealing of cavities or as a base for tooth fillings.
water distillation cannot be used for ___________________
Cannot be used for oils that decompose easily.
steam distillation can only be used for __________
Can only be used where significant amounts of oil are present and if the oil is not easily oxidised/hydrolysed.
in steam distillation, Machines called ______________ are available but the quality of the oil is inferior to that produced by the ‘hand method’.
‘sfumatrice machines’
what should be considered in distillation
Some oils are glycosides and these need to be hydrolysed [enzymatically or using mineral acid] before under taking distillation.
