Lemon Monograph (August 2017)

Download Sal’s Lemon Monograph PDF here.

The revitalising aroma of lemon has such a wonderful uplifting influence on our psyche. Worwood beautifully describes the way you feel upon inhaling lemon oil:

The sweet lemon is like a breath of fresh air on a summer’s day, positively wonderful to have around.

Synonyms

Expressed lemon oil

Family

Rutaceae

Botany and origins

Lemon species are divided into two groups with either smooth or rough-skinned fruit. Some taxonomists regard the two as distinct species; the smooth as C. limon and the rough (citronelle) as C.jambhiri Hodg. Others consider the rough lemon as a lime x citron hybrid.1

The lemon tree is believed to be a native of south eastern China. It is believed to have arrived in Europe via Persia and the Middle East with the returning Crusaders in the 12th century.1 However, Holmes states that the lemon tree was brought by the Moors to Sicily and Spain during the 10th century medieval Al-Andalus era.2

Columbus brought lemon and orange seeds on his second voyage to the West Indies in 1493. Little did he know he would be founding the world’s largest lemon industry by the 20th century.3

The lemon tree fruits all year round, the fruits appearing with a deep green colour and ripening to a bright yellow. Lemon is mostly cultivated in California and Florida and in Southern Europe.4

Nowadays the principal production areas of lemon oil are Italy, Spain, Israel, Argentina and the USA.1

Method of extraction

Lemon oil is obtained from the peel of lemons by cold expression. Weiss states that the rough lemon fruit has virtually no commercial use except as a seed source. Lemon peel will yield approximately 2.2% essential oil; however cold pressing normally returns only 66-75% of the oil.1

Steam distilling produces a higher yield, however, the distilled oil has different characteristics and is considered inferior.1

Characteristics

Lemon oil is a yellow to greenish yellow or pale yellow mobile liquid of a very light, fresh and sweet odour, truly reminiscent of the ripe peel.

There should be no turpentine-like, harsh terpene notes. Arctander states that the odour of lemon oil is not very lasting. However, good lemon oil should retain its fresh lemon aroma practically unchanged on a blotter until there is no odour left at all.4

Adulteration

Expressed lemon oil is frequently adulterated with distilled lemon oil, lemon terpenes, d-limonene (natural isolate or synthetic from pinene), synthetic dipentene, synthetic or isolated citral.4

Traditional uses

Lemon juice was considered to be a remedy for scurvy. English ships were required by law to carry sufficient lemon or lime juice for every seaman to have once daily after being at sea for ten days or more.5

The juice was used as a diaphoretic and diuretic. Lemon juice is highly recommended acute rheumatism and sometimes given to counteract narcotic poisons. The juice is a good astringent and is said to be the best cure for severe, obstinate hiccoughs and is helpful in jaundice and hysterical palpitation of the heart.5

Other uses

Lemon oil is extensively used in pharmaceuticals as a flavouring agent and as a fragrance ingredient in soaps, detergents and perfumes.6

Chemistry

Expressed lemon oil is comprised mostly (up to 70%) of limonene, a monoterpene hydrocarbon. A typical chemical composition of lemon is reported as follows:

α-pinene (1.8-3.6%), camphene (0-0.1%), β-pinene (6.1-15.0%), sabinene (1.5-4.6%) myrcene (1.0-2.1%), α-terpinene (0-0.5%), linalool (0-0.9%) β-bisabolene (0.56%), limonene (62.1-74.5%), trans-α-bergamotene (0.37%), nerol (0.04%), neral (0.76%).7

Properties

Antimicrobial, antirheumatic, antiseptic, antispasmodic, astringent, bactericidal, carminative, depurative, diaphoretic, diuretic, febrifuge, haemostatic, hypotensive, rubefacient, tonic.8,9

Pharmacology and clinical studies

Alzheimers disease

A clinical trial in Japan examined the effects of aromatherapy on patients with Alzheimer’s disease. Researchers examined the effects of essential oils in 28 elderly people, 17 of whom had Alzheimer’s. Rosemary and lemon essential oils were used in the morning and lavender and orange in the evening. All patients showed significant improvement in personal orientation related to cognitive function based on the assessment tools typically used for assessing the stage of dementia.10

Antifungal activity

Lemon essential oil has high antifungal activity in vitro against C.albicans.11

Antimicrobial activity

Lemon oil has high antimicrobial properties.12

Lemon essential oil vaporised in the air was effective in killing 40% of airborne microbes after 20 minutes and 90% after 3 hours.13

Cognitive improvement

A clinical trial tested the effect of odours on cognitive functions. Lemon oil was found to activate anticipation and attention processes. It was noted that the effect increased with increasing odour concentration. The researchers also noted that if a subject preferred a particular odour the effect of the odour was stronger.14

Anticarcinogenic

A review article on the role of d-limonene confirms that it has well-established chemoprotective activity against many types of cancer. Evidence from a phase I clinical trial shows a partial response in a patient with breast cancer and stable disease for more than six months in three patients with colorectal cancer. d-limonene induced phase I and phase II carcinogen metabolizing enzymes (cytochrome P450), which metabolises carcinogens to less toxic forms and prevents the interaction of chemical carcinogens with DNA.15

Schnaubelt explains that limonene inhibits phase I liver detoxification enzymes while simultaneously inducing phase II enzymes. This means that the production of potentially toxic or even carcinogenic compounds which can sometimes occur in the phase I process are slowed and the accelerated phase II process removes them instantly.16

Potential carcinogens cannot linger about under the influence of limonene. Therefore the limonene molecule selectively inhibits the reproduction of tumour cells via the inhibition of HMG CoA reductase. This is why we should eat citrus fruits or use essential oils that are rich in limonene such as orange or lemon.16

Anxiolytic activity

The anti-stress action of lemon, lavender and rose oil was examined using an elevated plus-maze task, a forced swimming test and an open field task in mice. Lemon oil had the strongest anti-stress effect in all three behavioral tasks. The pharmacological mechanisms were investigated and it was found that lemon oil significantly accelerated the metabolic turnover of dopamine in the hippocampus and of 5-HT in the prefrontal cortex and striatum. The results suggest that lemon oil possesses anxiolytic, antidepressant-like effects via suppression of dopamine activity related to enhanced 5-HT nergic neurons.17

Antidepressant activity

Studies suggest that the aroma of citrus essential oils can restore stress-induced immunosuppression. It is well known that the dysregulation of the neuroendocrine and immune function is associated with psychosomatic or psychiatric disorders. In one study, researchers created a citrus fragrance using lemon, orange and bergamot essential oils along with cis-4-hexanol (an aroma chemical with a green grassy smell). Twenty depressed male inpatients receiving antidepressant medications were divided into two groups. One group was given antidepressants alone and the other group was exposed to the citrus blend continuously whilst having their medication reduced weekly until their depression remitted (within four to eleven weeks). The Hamilton Rating Scale for Depression and the Self-rating Depression Scale were used to evaluate psychiatric states. Both scores were improved in both groups. By the end of eleven weeks, nine of the twelve patients in the citrus blend group had reduced their antidepressant drug intake to zero, whilst the other three had reduced their dosage by 50-75%. On the other hand, all subjects in the antidepressant group still needed their usual dose of antidepressants at remission. Urinary cortisol and dopamine levels were significantly lower after the treatment in the citrus blend group. The citrus blend group also had a significantly higher NK cell activity compared to the antidepressant group.

It was suggested that the use of citrus fragrances in the treatment of depression could be of psychoneuroimmunological benefit, although caution was recommended with the interpretation of this study due to the small size of the study.18

Gallstone dissolution

In vitro, d-limonene dissolved gallstones within two hours. In patients with post gallstone surgery an infusion of 20mL d-limonene every other day dissolved gallstones overlooked by surgery. In some patients gallstone dissolution occurred after only three infusions.15

Gastroprotective activity

A study investigated the gastroprotective mechanism of action from lemon oil, d-limonene and β-pinene. The minimum inhibitory concentration (MIC) against H.pylori was determined in vitro. Both lemon oil and d-limonene demonstrated very effective gastroprotective effect. It was suggested that the gastroprotective mechanism is involved with (PGE2) Prostaglandin E2.19

In a double-blind, placebo–controlled study 13 participants suffering from mild/moderate to severe heartburn were randomised to d-limonene or placebo. The limonene group received 1,000mg of d-limonene once a day in a capsule, while the placebo group received an identical capsule containing soyabean oil. By day 14, 86% of participants taking the d-limonene achieved complete relief of symptoms, compared to 29% of the participants in the placebo group.15

d-limonene has been shown to be effective in relieving occasional heartburn and gastroesophageal reflux disorder. In vitro studies suggest that it may neutralize the effect of gastric acid by coating the stomach wall and protecting the mucosal lining from gastric acid exposure.15

Neuroprotective activity

The in vitro effect of lemon oil on heat-shocked induced apoptosis of both human and rat astrocytes was investigated. The results demonstrated that the astrocytes pre-treated with lemon oil inhibited heat shock-induced apoptosis. Heat shock-induced DNA fragmentation (a characteristic of apoptosis) was inhibited by the lemon pre-treatment as was the condensation of nuclear chromatin, the activation of caspase-3 and the cleavage of poly-ADP-ribose polymerase (PARP). It was suggested that lemon oil may modulate apoptosis through inhibition of PARP cleavage by preventing caspase-3 activation. It was also suggested that lemon oil may have neuroprotective effects in the brain.20

Aromatherapy uses

Circulatory system

Lemon oil is an excellent tonic for the circulatory system, reducing blood viscosity and helping to break up plaque deposits in the arteries, reducing cholesterol.21,22,23,24 It is an excellent remedy for tonifying the blood vessels and it may be used on varicose veins, broken capillaries, haemorrhoids and nosebleeds.23,24

Fischer-Rizzi recommends mixing lemon oil in a 1 to 1 ratio with cypress oil in a skin lotion or compress for treating varicose veins.21

Detoxification

Lemon oil can be used as a mild detoxifier and is very useful for the treatment of toxaemia or for cellulite.9

Lemon oil can be blended with other essential oils to support liver regeneration and detoxification. This is why we should eat citrus fruits or use essential oils such as orange or lemon that are rich in limonene.16

Immune system

The oil is a very good stimulant of the immune system.21

Psychological

Worwood states that lemon oil clears the mind very effectively aids in the decision-making process without over stimulating the mind. It can be very calming for those who are emotionally overwrought. Lemon is described as a “rational oil” and is recommended it to calm stormy emotional outbursts or help to avoid them all together.21

Holmes recommends lemon oil for mental fatigue with poor concentration. It is beneficial for those who wake up in the morning feeling low energy. He also recommends lemon for eliminating negative thinking, pessimism and depression. He best sums up lemon’s influence on our psyche:

Lemon oil can also go a long way to dig us out of the rut of routine, habit-bound, unimaginative patterns of thinking. By creating light and clarity in the psyche, it can help shrink gloomy, negative, depressive thoughts – which can be considered a mental kind of congestive damp.2

Respiratory system

Lemon oil’s strong antiviral action makes it beneficial to alleviate colds and flu, especially when there is yellow or green catarrh.24

Skin care

Lemon oil acts as an astringent counteracting overproduction of sebum and is especially useful for teenage problem skin. It tones aging skin and has antibacterial properties that are beneficial for the treatment of acne and boils.9,23 It is recommended for treating warts and verrucae. For this purpose it is best to apply the undiluted oil.23

Tonic

Holmes describes lemon oil as a tonic and restorative for the entire body; 2

• Nervous restorative – for mental fatigue and exhaustion

• Liver restorative – for supporting liver detoxification functions

• Pancreatic restorative – for the management of hyperglycaemia and diabetes

Personality profile

Lemon personalities sparkle and are full of life, with a very positive approach in the form of an unshakeable confidence in everything that they do. Lemon is like a breath of fresh air, positively wonderful to have around, not too bothered by the struggles and strains of living and able to take everything quite calmly.25

According to Worwood, lemon personalities have an unshakeable confidence in everything that they do. This ‘never doubt yourself’ attitude can rub off on other people around, which is a blessing for personalities who have difficulty starting or finishing projects.25

Worwood states that while a lemon personality may appear sweet they can become very critical and not understand why others cannot do something as good as them. She says that they are inclined to become workaholics and will do better owning their own business where it is easier for them to set the pace.25

According to the principles of Myers Briggs, I am inclined to believe that lemon oil personalities are ENTJ.

ENTJs are typically dynamic, energetic, confident and competent. They naturally move into positions where they can take charge. They enjoy confrontation and they like to engage in intellectually stimulating exchanges. They like and respect people who challenge them and have little or no respect for those that don’t. They are competitive and driven. They are often workaholics. They like to be in charge of making decisions. They can have explosive outbursts or be judgemental on themselves and others when stressed. They live life with passion and enthusiasm.

Subtle aromatherapy

Fischer-Rizzi describes lemon as an essential oil with high vibrations. She explains that essential oils with high vibrations lift one’s spirits, especially when one may be feeling mental fatigue.21 Worwood states that lemon oil is spiritually cleansing. It enables the entire psyche to react to the positive in mortal, as well as divine, love.26

Mojay compares lemon oil to rose oil. He says that lemon oil can encourage greater trust and security. It can help to open the heart – by alleviating fears of emotional involvement and of losing oneself in another person.24

Zeck refers to lemon oil as a delightful aromatic spa for the brain:

If you are feeling confused and out of your depth, lemon’s bracing and enlivening effect upon your senses will sharpen your progress, clear your head and pave the way for rational thinking.

Confusion can bring irrational emotional outbursts and such behavior are usually not welcomed or tolerated by others. Lemon helps to cut through confusion and is a delightfully aromatic spa for the brain.27

She also states that lemon oil will enhance rational, logical thinking and any intellectual pursuits.27

Energetics

Lemon oil is cooling and drying and it is recommended to clear heat, dampness and phlegm. For this reason, it is considered an excellent detoxifying essential oil.24

Mojay explains that lemon oil acts mainly on the Earth element as it is a pancreatic stimulant and mental decongestant.24 However, considering it is such a powerful hepatic I suggest that it also has a very strong affinity with the Wood element.

According to the principles of Five Elements lemon oil would tonify the Wood element and help to reduce excess damp associated with the Earth element. According to the principles of Ayurveda, lemon oil would strengthen Vata and Pitta and help to reduce Kapha.

How to use

Bath: Typically for a full body bath in a tub, use up to 5 drops of essential oils in the tub of warm water. Foot or hand baths may be prepared by adding 2-3 drops of essential oil to a bowl of warm water.

Massage: Use a 2.5% dilution of the appropriate blend of essential oils to the chosen carrier oil. A 2.5% dilution equates to 5 drops of essential oil to 10mL of carrier oil.

Inhalation: The best way to use essential oils for inhalation is by diffusing them. When you are using essential oils in an ultrasonic diffuser, please follow the instructions of the diffuser that you are using.

Internal ingestion: Schnaubelt recommends a treatment for anyone who is interested in optimum health to prevent the accumulation of toxins in the body. He explains;

It is done simply by ingesting an essential oil such as lemon oil, which will trigger or modify the detoxification process.16

Schnaubelt suggests taking 1 drop of essential oil in a glass of water.16

There is one strict rule that I would like to add – the oil must be certified organic and only once a day for several weeks at a time.

Blending tips

Lemon oil is extensively used in perfumes for its refreshing, sweet fruity note. Arctander says it is the most important ingredient in old-fashioned citrus-type colognes and is used as a top note ingredient in many perfumes.4

Lemon adds such a refreshing top note to all aromatherapy blends. It can often be used liberally in a blend without having a strong impact on the overall aroma of the blend.

When making a detoxifying blend always include some lemon oil. Essential oils such as juniper berry, sweet orange, grapefruit, everlasting and rosemary are also perfect to use for any detoxification blend with lemon oil.

I love lemon oil in any blend where you want to promote mental clarity, alleviate fatigue and tiredness. Lemon blends well with essential oils such as basil, rosemary, black pepper and peppermint. I also love blending spice oils with lemon. The fresh, invigorating scent of lemon softens and compliments the spicy, warm scent of oils such as ginger, black pepper, clove bud and cinnamon bark. Such blends would be quite energising and warming and may be used to alleviate fatigue or to ease muscular aches and pain.

Lemon oil blends exceptionally well with tea tree, eucalyptus and lavender to create an exceptionally effective antiseptic and antimicrobial blend.

Perfect Potion classics with Lemon

Lemon oil is the star essential oil in our uplifting and energising blends such as Refresh and Focus.  Its antimicrobial properties work in synergy with eucalyptus and tea tree in Breathe Easy oil and it creates a very effective room purifier in Breathing Space Room Spray.    

Lemon oil helps to balance excess Kapha so it is an important addition to our Kapha Blend.

Lemon adds a breath of fresh air and vibrant energy to Daphne and Hecate Emgoddesses blends.

Lemon blended together with cypress and peppermint make Cooling Foot & Leg Lotion such an excellent product for alleviating tired, aching legs and working as a venous restorative.

If you are feeling tired after a long flight, lemon blends well with geranium and peppermint in Jet Setter Aromatic Mist to give you mental clarity and freshness. Blended with peppermint it enhances the cooling qualities of peppermint in our beautiful Cool Mint Aromatic Mist.

Lemon has a strong affinity with the solar plexus chakra – hence it is used in Harmony chakra blend.  It gives us willpower and self-confidence. It is not surprising that we have also used lemon in our Chakra Balancing range

Together with tea tree and lavender, lemon makes our Aromatherapy Hand Sanitiser the most effective natural antimicrobial hand sanitizer in the World!

Lemon is the heart and soul of Solh Peace Perfume which showers you with an enlivening burst of citrus aromas.

Safety

In The Complete Guide to Aromatherapy, I stated that lemon oil is non-toxic, non-irritant. Sensitisation can occur in some people and it should not be used on the skin prior to exposure to the sun as it is phototoxic.8,9,21,23,24,28

Tisserand states that the oil is sensitising if it is oxidised. He cites IFRA standards that recommend expressed lemon oil be limited to a maximum of 2% in products applied to the skin. This does not apply to soaps or wash off products.28

If it is applied to the skin at over the maximum use level recommended by IFRA, the skin should not be exposed to sunlight or sunbed rays for 12 hours.28

Schnaubelt recommends only using lemon oil obtained exclusively from certified organic grown fruits that are pesticide-free because most industrially cultivated citrus plantations are invariably sprayed with heavy doses of chemicals.16

I totally agree!

 

References

For the full list of references, please see the PDF here.

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