The Essential Oils Are Complex Mixtures Biology Essay

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Essential oils are complex mixtures of many components, about 20-60 can be present at differnet concentrations depending on the oil biological activity.According to bakkali et al(2008) they are characterized by components of the highest concentrations, there are usually 2 or 3 main components in each oil compared to some components in trace amounts.The GC MS analysis carried out showed cinnamon oil produced 86.9% tran cinnamaldehyde shown in Figure 1. Whereas lemongrass oil produced 51.3% geranial 37.4% citral.

Major components of the oils determine the biological activity of the oils.Chemical analysis of lemongrass and cinnamon oil distinguished sevral compounds .Cinnamon oil presents eugenol(put in nmber) cinnamldehyde and acetoeugenol as major components.Lemongrass exhibited geranial and geranial acetate as major components of this oil.whikst others detected in lower concs. Common constituents shown in table…

Although major components are known to be the reason for the antifungal effect it has been suggected that minor compounds may have a synergistic or additive effect.(tyagi and malik 2011) however found in lopezs paper)

Similar concentration as what I have found have been previously reported (from lopez paper) by Inouye et al

GC MS analysis was carried out on the carrier oils however as they do not contain volatile compounds as essential oils do they did not produce any readings

Essentai oils cannit be used ontheir own as they are classed as irritants according to health and safety (Look at COSHH form)thereore a method is required where the oil is not as concentrated and can be used in application such as sprays where it is easier to distribute.Essential oils are expensive therefore if mixed with a carrier oil which are usually cheaper and more readily available.

4.2 Vapour phase

Candida glabrata has shown when essential oil in the vapour pahse fungicidal effect where the oil is direcly placed underneath the candida therefore it has no time to grow here therefore a fungicidal effect is produced Once the vapour moves out the concentration isn't high enough thefore produces a fungistatic effect as the vapour gets to the outer edges it isn't able to do anything as the concentration isn't concentrated enough.Therefor a dispersal method would be mofre effective as there would be an even distributionof the oil.

Tyagi Malik 2010-"Vapour phase: thought that essential oils in liquid medium lipohilic molecules form micelles and supress attachment of the essential oils to the organism whereas the vapour state allows for free attachment" some studies have been carried out using the vapour phase but no standard assay exists to evaluate inhibition by vapour phase contact according to Aviva-Sosa et al.(Du et al)

If volatile compounds retained less effectively therefore allowing more molecules in the vapour phase with increased antifungal activity promotes fungicidal effect at lower concentrations(lopez)

Tyagi and malik in liquidtha activity depends on the diffusability and the solubility of the essential oil while vapour depends on the volatility of each compound.since active compounds are highly volatilepresence in gaseous form can better facilitate the solubilisation of lipophilic monoterpenes in cell membranes thereby inflicting higher damages as compared to the liquid phase.(in lemongrass paper)

Tyagi andmalik found that lgo vapours vapour are more potent than lgo for irreparable damage to candidacells.They also noted that LGO vapours can cause damage at a much lower concentration this is thought to be due to better penetration and contact.(lgo vapours)

The major antimicrobial components (terpenes)are available and enriched in the LGO vapour(in lgo vapour paper)

4.3 Bonding and compounds

Carbon and oxygen form a polar bond (carbonyl group C=O)therefore if this bond is part of a molecule it affects how the molecule behaves making it more reactive. The greater the difference in electronegativity of molecules the greater the polarity of the bond. Polar molecules are hydrophilic(water loving)whilst most essential oil as are generally insoluble if a part of it has a polar molecule it will be slightly soluble to a certain extent.Polar bonds have have different electonegativities and therefore unequal sharing of the bonding electron pair.This results in a bond where the electron pair is displaced towards the more electronegative atom.The atom obatains a partial negative charge while less electron negatiove has a partial positive charge.Non polar molecules are hydrophobic (water hating) Non polar compounds share the same electronegativity therefore have equal sharing of theelectron bonding pair (Aromatherapy :A practical approach Vicki Pitmn) Because non polar mlecules do not have a partially negative region it cannot take part in bonding therefore cannot mix with polar molecules .Essential oils are of mixed polarity. With some polar and some non polar compounds in the oils . No attraction between polar and

Carrier oils are non polar molecule has electrons equally distributed therefore will not be attracted to polar molecules . In carrier oils there is a mixture of short carbon structures which are non polar and longer carbon chains which are non polar more so for the reason that the longer the carbon chain the compound becomes less soluble in wwater the molecule becomes more like a hydrocarbon chain(organic chemistry book).Therefore depending on the structures in the carrier oils this affects how they interact with the essential oils.

The carrier oils with higher percentage show that the antifungal components are release even when mixed with carrier oil therefore dispose not reduce the activity of cinnamon oil. The choice of oil affects the cinnamon oil

4.4 Carrier oils

The essential oil is likely to have an attraction for the polar molecules in the carrier oil which will hold back the polar molecules in the essential oil which may be why some of the carrier oils do not work as well as others.

Therefore it is essential to find the structure of carrier oils as it will depend on how long the hydrocarbon chains are in working ouyt which oil is best as a carrier oil.This has been found to be

Terpenes are able to form structurally and functionally different classes. They are made from combinations of several 5 carbon units called isoprene .A monoterpene is formed by the combination of two isoprene units (C10)(bakkali 2008) According to Bakkali they constitute 90% of essential oils.Lemongrass oil contains a high percentage of geranial.This is an aldehyde.Citral was also found to be present in lemongrass oil, it is a mixture of two isomeric acyclic aldehydethis is a mixture of geranial (trans citral and neural (cis citral)

Whereas the main source of cinnamon oils major component is tran cinnamaldehde.An aromatic compound , which occur less frequently than terpenes(bakkali) .Cinnamaldehyde is also an aldehyde

Figure 21? Citral (saddiq.monoterpenes)left trans? Cis? Neral right.

Figure 21 represents structure of citral in cis and trans isomerism.

http://www.sigmaaldrich.com/medium/structureimages/00/mfcd00007000.png

Figure 22: trans cinnamladehyde structure(Sigma Aldrich)

The literature reports from tyagi and malik one of the main reason for drug resistance with c albicans biofilm appears to be limited penetration of drugs inside the exopolymeric mtrix which can result in binding or restriction the diffusion of the antifungals .LGO vapours can overcome this barrier and and act as better antifungalsthan lgo in the liquid phase.

Palmitic

Palmitoleic

Heptadecanoic

Ginkgolic

Stearic

oleic

Linoleic

Linolenic

Arachidic

Gadoleic

Behenic

Erucic

Tetracosanoic

C16:0

C 16:1

C17.0

C17:1

C18:0

C18:1

C18:2

C18:3

C20:0

C20:1

C22.0

C22:1

C24:0

Groundnut oil

8.0

4.0%

52.0

4.0

16.0

Extra virgin olive oil

14.9

1.84

0.04

0.09

2.00

69.6

10.1

0.59

0.35

0.23

0.11

0.04

Rapeseed oil

4.0

1.5

17.0

13.0

9.0

14.5

41.0

Wheatgerm oil

12.5

0.2

2.5

27.3

53.7

3.0

0.4

0.2

0.1

Walnut oil

6.0

0.1

4.0

29.8

58.5

0.4

0.3

0.2

Sweet almond oil

5.5

0.2

2.8

70.0

21

0.1

0.1

0.1

0.1

Sunflower oil

5.8

0.1

3.9

15.9

71.7

0.1

0.3

0.2

0.7

0.5

Grapeseed oil

6.5%

0.2

3.7

23.4

65.3

0.2

0.2

0.2

0.2

Parrafin oil

Table 5: lemongrass order of results

Palmitic

Palmitoleic

Heptadecanoic

Ginkgolic

Stearic

oleic

Linoleic

Linolenic

Arachidic

Gadoleic

Behenic

Erucic

Tetracosanoic

C16:0

C 16:1

C17.0

C17:1

C18:0

C18:1

C18:2

C18:3

C20:0

C20:1

C22.0

C22:1

C24:0

Sunflower oil

5.8

0.1

3.9

15.9

71.7

0.1

0.3

0.2

0.7

0.5

Extra virgin olive oil

14.9

1.84

0.04

0.09

2.00

69.6

10.1

0.59

0.35

0.23

0.11

0.04

Sweet almond oil

5.5

0.2

2.8

70.0

21

0.1

0.1

0.1

0.1

Groundnut oil

8.0

4.0

52.0

4.0

16.0

Grapeseed oil

6.5%

0.2

3.7

23.4

65.3

0.2

0.2

0.2

0.2

Parrafin oil

Walnut oil

6.0

0.1

4.0

29.8

58.5

0.4

0.3

0.2

Rapeseed oil

4.0

1.5

17.0

13.0

9.0

14.5

41.0

Wheatgerm oil

12.5

0.2

2.5

27.3

53.7

3.0

0.4

0.2

0.1

Cinnamon oil order of results

The tales represent the components in the oils and wether or not they are saturated or unsaturated.There is a lot of variation between how the carrier oils worked with lemongrass oil and cinnamon oil.With lemongrass oil groundnut oil produced the highest level of inhibition whereas with cinnamon oil sunflower oil produced the highest zone of inhibition compared to the controls.

These oils are non polar

Essential oils and acrreir oils are covalently bonded

Carboxylic acid group

Hydrocarbon chain

Figure 24: Hydrocarbon chain

The carrier oils are composed of two chemically bonded components a fatty acid and glycerol .The fatty acid molecule is made up of a hydrocarbon whose length varies according to the type of fatty acid this is hydrophobic whereas the carboxylic acid group is hydrophilic.the structure of the hydrocarbon is different for different fatty acids by length aswell as the type of carbon to carbon bonding .Saturated chains contain single bonds whereas unsaturated ones contain one double bond known as monounsaturated or more than one double bond polyunsaturated.(aromatherapy book)

+

Wheatgerm oil did not work aswell this has a high amount of c16 therefore this could be the acid which may be holding the essential oil components wheras linoleic acid

Acids with only a few carbons the acid functional group is dominant giving thewhole molecule polar chracteristics however in fatty acids the non polar hydrocarbon chain gives the molecule a non polar character.

When non polar molecules enter aqueos medium some bonds are likely to be broken to create a cavity for the solute molecule

Greater saturation less likely to interact with polar

The larger molecules hold the molecules of the essential oils therefore the antifungal properties are not released.

An acid has both a non polar alkyl group and a polar OH group.As the alkyl group increases in size it becomes a more significant fraction of the molecule and becomes less soluble in water.The molecule therefore balances out(organic chemistry).If the hydrocarbon chain is shorther the polar group becomes more significant.Table 7? Shows an increase in alkyl groups from 16 molecules (C16) to 24 as the size increases the less polar the molecule is.As the chain increases there are greater Van Der Waals forces between molecules so non polar molecules have non polar bonding.

Molecules with double bonds such as oleic acid cause a bend in the molecule this forces thechains apart from each other therefore Van der Waals forces are not present.therefore the more double bonds the fewer Van der Waals forces so components more likely to vaporise and the molecule of the carrier oil are likely to be released as normal.

As the chain decreases vthe polar attractions are more important ionic and Van der Waals less so.Hydrogen bonding becomes more important.Hydrogen bondsare fromed when hydrogen is bonded to the lone pair of electrons on the oxygen.This is the strongest type of interaction(organic chemistry book.) Therefore shorter acid chains aremore likely to hydrogen bond with polar molecules of the essential oil.Whereas the non polar molecules which do not bond and only Hve weak vand der waals forces are likely to vaporise.Cinnamon oil has cinnamaldehyde the largest amount this contains a benzene ring which is non polar however the aldehyde is polar.Overall the molecule is non polar.As the benzene ring is flat Van der waals forces can occur between molecules therefore shorter acids from the carrier oils can bond with cinnamaldehyde.Citral is non polar it also contains double bonds therefore the bends cause less attraction which means fewer Van der Waals forces between molecules..This molecule also contains an aldehyde group at the end however it is less non polar than cinnamaldehyde as it contains fewer double bonds therefore is able to create more Van der Waals forces between molecules.

This creates the basis of how the bonding affects the vapour phase and volatility of the compounds.When lemongrass oil was combined with the range of carrier oils,groundnut oil produced the best zone of inhibition.The more double bonds a compound contains the fewer Van der Waals forces .This is demonstrated by the melting points of these 4 components as the number of double bonds in the molecule increases the melting point decreases.

Bandages

In natural textils the essential oils cane be fixed by Vand er waals forces(physical bonding or Covalent bonds(chemical bonding).the essential oils are of mixed polarity therefroe the affinity between the textile and the essential oil is mixed depending on the composition of the textile as each bandage contains a different percentage of material although they may contain similar components. Textiles may be classified as two types. Non polar, synthetic polymers and polar natural textiles.This can be further diided into polymers from amino acids such as silk and wool or from cellulose such as cotton.

All fibres are made of polymers .Polymers are formed when hungreds and thousands of small molecules are covalently bonded into a linear chain.The backbone of most polymers for textile fibres contain covalently bonded carbon atoms. Non polar groups are usually less reactive than polar groups.Non polar molecules attract each other via weak forces known as Van der Waals forces.

Bandage

Composition

Tubuar

85% cotton, 10% latex, 5% polyester

Non woven bandage

100% viscose(medical textiles paper)

Stretch bandage

36%cotton, 36%viscose,28%polyamide

Crepe

Cotton mixed with wool

Cotton crepe

100 percent high twist cotton and rayon yarns

Gauze

100% hydrophilic cotton gauze

Cotton

waxes, fatty substances 0.40%

mineral salts 0.20%

http://www.tis-gdv.de/tis_e/ware/fasern/baumwoll/baumwoll.htm

non adherent

porous polyethylene film and absorbent cotton pad.

Lint

92% cellulose 2% hemicellulose lignin 4% others 2

http://textilefashionstudy.com/chemical-composition-of-flax-fiber-linen-fiber-composition/

Citral is non polar(hydrophobic effect paper) as is cinnamaldehydetherefore theya re likely or not likely to be released into the vapour phase or stay on the material depending on if the material is hydrophilic or hydrophobic.howeverthis is not the only factor.as there are other componenets involved in this if some of the results are not in line with this hypothesuis then it may be because of the smaller constituents involved which may be polar or non polar.

Cinnamon oil

Lint produced the best results with inhibition at 80%.Absorbent lint is composed of cotton. Cotton is the ost common cellulosic fibre.Hydroxyl groups are mainly present in the structure of cellulose.They are knownto be hydrophilic , water loving therefore any non polar9hydrophobic) molecules will not stick to the surface and will therefiore not likely to absorb and be released as normal into the vapour phase. This is the same as gauze composed of 100% hydrophilic cotton gauze therefore this produced similar results to lint at 76.8%.

However this is not shoen by cotton which produced a low result of 33£ although at 1 micrlitre it gave a result of 32.9% therefoe not much difference between 25 and 1 ul however cotton contains a small amount of water which is highly polar……………………… .comparing to cotton crepe and crepe.Cotton crepe produced only a slightly better result than crepe at 25ul however it produced better results at all concentrations therefore reiterating the polarity effect . Cotton crepe: 100 percent high twist cotton and rayon yarns.Rayon is viscose it has the same polymer structure as cellulosic fibres which is the same as cotton.

The results at the synthetic fibres shower a significant reduction. Non woven material material has a wide range of use in the medial=cal field.they are disposable, sterile and cheap. And are beneficial in prevention ofc ross infection. Non woven 100% viscose.highly prous alow air and water permeability. Tubular bandages are composed of cellulose and elastic fibre such as latex bledds in the knit structure. This is hydrophilic whereas the polyester is hydrophobic.Although there is a small amount of polyester the the hydrophobic therefore the hydrophilic components attract the polar molecules in the essential oil wheras the non polar in the bandage attract the non polar in the oil by Vander waals forces however as they are only weak they can be broken which is where some of the components are released as a vapour creating a zone of inhibition. Stretch bandage 36% cotton therefore cellulosic and hydroxyl bonds present.Polyamidein this is nylon.Nylon is hydrophobic although ithas the highest absorption capacity among synthetic fibres because of the polar amide group present.Viscose is also a cellulosic fibre.So in this fibre there are more hydrophilic groups than hydrophobic. non adherent :porous polyethylene film and absorbent cotton pad.Usually used for burns.Hydrophobic polyethylene flm with absorbent cotton pad.

Lemongrass oil

With lemongrass oil Crepe produced a 100%inhibiton.Crepe has a high polarity as it is mix of wool and cotton. Wool has the highest capacity of water absorption contains hydrophilic functional groups primary amine NH2 and carboxyl these structural fetures contribute to its ability to. As does cotton.

Crepe, cotton gauze, lint. Cotton crepe. Then tubular non adherent stretch non woven

Cotton 90.5%.Cotton produced a much highere result with lemongrass oil than with cinnamon oil.This may be because of the polarity of the molecules or the difference in plarity of the molecules.Citral is less non plar than cinnamldehyde because of the kinks In the moledcvul;e.It maybe effects of other compionents in the oil.Gauze and lint also produced zones of inhibition between 70 and 90%

Tubular ,non adherent ,stretch and non woven bandage produced the lowest results .Showing the same general trend with cinnamon oil although in a slightly different order of reactivity.This is caused by the lower polarity of these fibres as they contain hydrophobic compounds .They are likely to produce Van der Waals forces and thereore not released as a vapour.Although the textiles did produce inhibition the lowest being 45% with the non woven bandage.This is suggestive of additive effects of other components in the oil. suggest that the antifungal components arenon polar and the major ones of this is citral and cinnamaldehyde.

4.5 Biological effects

The structure and function of fungal cell wall pubmed paper)

The degree of fungal inhibition depended on the carrier oil icrporated with the essential oil as different carrier oils retain components of the two essential oils to different degrees.

(an example oil) was the least effective as .This may be because the different components in the carrier oil interacting with the main components of the essential oils this could potentially affect the antifungal activity no significant differences were found at low concentrations?

According to(biological effects) essential oils are not thought to have any specific cellular targets as they have many constituents.As lipophiles they pass through the cell wall and cytoplasmic membrane and disturb the structure of their different layers of polysaccahrides fatty acids and phospholipids and make them permeable. Essential oils can coagulate the cytoplasm (Gustafson et al 1998 from bio paper) and damage lipids and proteins. Damage to cell wall and cell membrane can lead to the leakage of macromolecules and to lysis.I n eukaryotic cells essential oils can aggravate depolarization of the mitochondrial membranes by decreasing the membrane potential affecting ionic Ca++ cycling(richter and schlegel1993), Novgorodov and Gudz 1996)and other ionic channels and reduc the pH gradient , affecting the proton pump and the ATP pool.They change the fluidity of memranes which become abnormally permeable resulting in leakage of radicals,cytochrome C,calcium ions and proteins.Permeabilization of outer and inner mitochondrila membranes leads to cell death by apoptosis and necrosis.seems that chain reactions from the cell wall or the outer cell membrane invade the whole cell,through the membranes of different organelleslike mitochondria and peroxisomes.

Terpenes which are the major components of essential oils , alter cell permeability,by penetrating between the fatty acyl chainmaking up the membrane lipid bilayers disrupting lipid packing and changing membrane fluidity.this leads to morphological alterations reducing adherence capacity of c.albicans(germ tube formation paper)

One study found(germ tube formation) that Candida albicans treated with lemongrass oiland its major constituents had reduced ability of germ tube formation.

With lemongrass oil vapours it was found that the vapours are able to enter (tyagi and malik) components are able to enter and alter the permeability of the cell by disrupting the fatty acyl chain making up membrane lipid bilayers therefore properties of the membrane maybe changed.which may affect the regulation and function of membrane bound enzymes and may alter the synthesis of components of the cell wall polysaccharides such as beta glucan chitin and mannan.and alter cell growth and morphogenesis.

The major components of the LGO are terpenees which have the ability to to inhibit respiration of Candida and may have adverse effects on mitochondria. Add area from othere paper here about mitochondria.

Synergism:

If the results of the are due to synergism or reflectonly thse of only the highest level which were shown by gas chromatography.the major components are found to reflect the biological activity of the essential oil,the amplitude of their effect being dependent on on their concentraton.It is possible the activity of the main components is modulated by minor molecules.it is suggested by (cal,2006)that several components of the essential oil play a role in defining the amount of cell penetration,lipophilic or hydrophilic attraction and fixation on cell wall and membranes as well as cellular distribution.Cellular distribution is an important feature as because the distribution of the oil in the cell determines the diferent types of radical reactions produced depending on the compartmentation in the cell.

Specificity

Lemongrass oil and cinnamon oil vey few studies have analysed enough essential oils and biological endpoints to determine wether there is specificity for different effects according to different oils.It has been demonstrated by Bakkali et al that there is a difference in the amplitude but not in the mode of action of the biological effects.(bilogocal activit)

Tyagi and malik lgo found tat phenols and aldehydes exhibited the highest vapour activity followed by alcohols ketones and esters and lastly hydrocarbons..This study found that lemongrass oil had a higher antimicrobial effect than citral indicating the synergistic role of other vaporcomponents such as limonene and linalool. Therefore the compounds in lemongrass oil could have shown synergistic or additive effects enhancing the antifungal effect. Both cinnmaldehyde and citral are aldehydes so although they are the most volatile does not suggest only work on their own therefore when mixed with carrier oils the

One study specifically investigated the role by studying its effect on sterol biosynthesis ans plasma membrane ATPase activity of fungi.ATPase is an important fungal pump it creates a membrane gradient which is used for transport of nutrient.The pump is activated in th presence of glucose which forces more H+ ions out.The Cndida isolates which demonstrated suceptibilty to cinnamaldehyde also showed inhibition of H+ ATPase mediated proton pumping the study suggested the two actions are linked.The study also found that cinnamaldeyde may have a similar mode of action to fluconazole as it inhibits ergosterol syntheisis in sensitive strains.as the essential oil blocks the synthesis of ergosterolfound that cinnamaldehyde acts in a dose dependent manner in decreasing ergosterol.suggests that these are the primary target of cinnamaldeyde.( Spice oil cinnamaldehyde exhibits potent anticandidal activity against fluconazole resistant clinical isolates)

Further studys

Further studies that could be carried out include exposing at different time periods( kill time assay) an hour then four hours( how much growth inhibited)

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