Esters Found in Essential Oils

The Amazing Esters Found in Essential Oils

By Kathy Sadoswski MS, LMT, RYT

This article originally appeared in the NAHA Journal (Winter, 2017) and  it is republished here according to the NAHA Writer Guidelines 2017-2018 statement.

Esters are oxygenated compounds that occurs during the “esterification process” when an acid combines with an alcohol, resulting in the formation of an ester along with a water molecule. This creates a typically gentle and strongly aromatic chemical found in essential oils. Esters are easily formed and broken down during the distillation process; an example of this is the combination of linalool with acetic acid, which forms the ester linalyl acetate plus water.¹ Made from the combination of an alcohol and an acid, its name is derived from both parent molecule such that the combination of linalool and acetic acid is named the ester: linalyl acetate. Best known for its sweet floral aroma, an ester also has the following therapeutic properties: Antimicrobial, anti-inflammatory, antispasmodic, calming, and skin vulnerary actions.² These constituents make for an excellent inclusion in a topical blend with their therapeutic actions and very low skin sensitizing and toxicity levels.

Examples of esters in essential oils include:

• Benzyl acetate as found in jasmine absolute (Jasminum officinale) and ylang ylang (Cananga odorata)
• Benzyl benzoate as found in peru balsam (Myroxylon balsamum), benzoin resin (Styrax benzoin and Styrax tonkinensis), jasmine (Jasminum officinale), and ylang ylang (Cananga odorata)
• Bornyl acetate as found in pine (multiple Pinus species), spruce (multiple Picea species), fir (multiple Abies species), rosemary (Rosmarinus officinalis), sage (Salvia officinalis), and valerian (Valeriana officinalis)
• Citronellyl formate as found in geranium (Pelagonium graveolens)
• Eugenyl acetate as found in clove (Syzgium aromaticum) and cinnamon (Cinnamomum verum)
• Geranyl acetate as found in sweet marjoram (Origanum majorana), thyme (Thymus vulgaris), palmarosa (Cymbopogon martinii), carrot seed (Daucus carota), neroli (Citrus aurantium), coriander (Coriandrum sativum), and citronella (Cymbopogon nardus)
• Linalyl acetate as found in lavender (Lavendula officinalis), clary sage (Salvia sclarea), bergamot (Citrus bergamia), and petitgrain (Citrus aurantium)
• Neryl acetate as found in helichrysum (Helichrysum italicum), fenugreek (Trigonella foenum-graecum), and citrus oils (multiple Citrus species)

Essential Oils High in Esters

• Chamomiles (Matricaria recutita and Chamaemelum nobile): Containing isobutyl angelate, 2-methylbutyl angelate, and methallyl angelate.
• Clary sage (Salvia sclarea): High in linalyl acetate.
• Helichrysum (Helichrysum italicum): High in neryl acetate.
• Lavender and lavandin (Lavandula angustifolia and intermedia): High in linalyl acetate.
• Myrtle (Myrtus communis): Containing myrtenyl acetate.
• Petitgrain (Citrus aurantium amara (fol)): High in linalyl acetate.

yarrow and lavender

Therapeutic Actions of Esters

• Anti-inflammatory
• Anti-microbial
• Antispasmodic
• Calming / sedative
• Skin vulnerary.

Cautions: While most esters are considered gentle, two exceptions include methyl salicylate as found in wintergreen (Gaultheria procumbens) essential oil, and sabinyl acetate as found in Spanish sage (Salvia lavandulaefolia) essential oil.1 Furthermore, it is important to be aware of other constituents in an essential oil that can be toxic and/or sensitizing. For example, clove bud (Syzygium aromaticum) essential oil contains up to 10% of the ester eugenyl acetate, but it also can contain over 75% of the phenol eugenol, which can be a dermal irritant, toxic, and carcinogenic when used improperly and excessively.³

Scientific Research on the Therapeutic Actions of Esters  

Benzyl acetate, as found in jasmine absolute and ylang ylang essential oils, has a sweet, fruity aroma often used in perfumery. It can make up to 25% of jasmine absolute.3

Benzyl benzoate has a faint, sweet, balsamic, floral aroma as found in balsam, benzoin resin, jasmine absolute, and ylang ylang essential oils. It is identified on the World Health Organization list of essential oils, and it has been used to treat scabies, lice, and used as an insecticide.^4,5 In addition, benzyl benzoate may be helpful in reducing dust mites by applying it to carpets and adding it to the laundry.^6.7

Bornyl acetate, with a woody, pine, herbal aroma, is found in tree species of essential oils like pine, spruce, and fir, as well as in rosemary, sage, and valerian. It has demonstrated the potential for improving bone density⁸ and it can also be used as a sedative, related to valerian root (Valeriana fauriei) and its constituents borneol, isoborneol, bornyl acetate, and isobornyl acetate, which has caused a sedative effect in mice.⁹

Citronellyl formate, also called tiglate, has a green, floral aroma and it can make up to 12% of geranium (Pelargonium graveolens) essential oil.³ It was found to show potential anti-tumor activity in a 1988 study.¹⁰

Eugenyl acetate, which is found in both clove bud and clove leaf (Eugenia caryophyllata) essential oil, as well as cinnamon leaf (Cinnamomum zeylanicum) essential oil, has a fresh, woody, spicy aroma and it has demonstrated antioxidant activities in vitro comparable to those found in vitamin E.¹¹

Geranyl acetate, with an aroma that is sweet, floral, fruity, and green, is found in sweet marjoram, thyme, palmarosa, carrot, neroli, coriander, citronella, ylang ylang, lemon balm, and lemongrass essential oils. It has shown to have antibacterial action.^12,13

Linalyl acetate has a sweet, herbal, floral aroma as found in lavender, clary sage, bergamot, and petitgrain essential oils. This constituent has shown in research to have anesthetic, anti-inflammatory, anti-cancer, antibacterial, and anxiolytic actions.

• Bergamot (Citrus bergamia) essential oil had anti-nociceptive and anti-allodynic effects that could be used to treat chronic pain. Linalool and linalyl acetate were key constituents.¹⁴ Furthermore, lavender (Lavandula angustifolia) essential oil, and its linalyl acetate and linalool constituents, had a local anesthetic effect in rats.¹⁵

• Linalyl acetate and citronellyl acetate showed antispasmodic activity in the rat ilium.¹⁶
• Linalool and linalyl acetate were anti-inflammatory in rats.¹⁷
• Bergamot (Citrus bergamia) essential oil with a combined action of its monoterpenes component limonene and the component ester linalyl acetate aided in cancer cell death induced by cytotoxicity in vitro.¹⁸
• Petitgrain (Citrus aurantium), lemon (C. limon), lavender (Lavandula angustifolia), German chamomile (Matricaria chamomilla), peppermint (Mentha piperita), spearmint (M. spicate), basil (Ocimum basilicum) oregano (Origanum vulgare), thyme (Thymus vulgaris) and clary sage (Salvia officinalis), along with their constituents were tested against human pathogenic bacteria. Significant constituents included: Carvacrol, linalyl acetate, and others.¹⁹
• Linalyl acetate and linalool that are found in clary sage (Salvia sclarea) essential oil were antifungal in vitro against three soil-borne pathogens.²⁰
• Linalyl acetate worked synergistically with linalool as an inhaled anti-anxiety treatment.²¹ The constituent demonstrated a sedative effect upon inhalation.²²

Neryl acetate has a floral aroma as found in citrus oils, fenugreek, and helichrysum, and it has shown to have pain reducing, inflammatory reducing activity used with cosmetic surgery. In a 2007 study, helichrysum (Helichrysum italicum) essential oil combined with a macerated oil of musk rose (Rosa moschata) was shown to reduce inflammation, edema, and bruising after cosmetic and reconstructive surgery, with the component of neryl acetate also contributing to pain relief.²³ Furthermore, the a-terpinolene, trans-carlophyllene, and neryl acetate components of helichrysum (H. italicum) (Roth) Don essential oil showed antimicrobial activity against the Micococcus luterus bacteria, which commonly infects the human respiratory tract.²⁴

Aromatherapy Recipes

Skin Saving Herbal Oil

Tincture Ingredients:

• 1 oz. dried burdock root (Arctium lappa)
• 1 oz. dried yellow dock (Rumex crispus)
• 1 oz. dried plantain leaf (Plantago major)
• 1 oz. dried calendula blooms (Calendula officinalis­)
• 3 pints of vodka (at least 40% alcohol)
• Large glass jar

Oil or Lotion Ingredients:

• 2 oz. of tincture from step one
• 4 oz. of jojoba (Simmondsia chinensis)
• 2 oz. of wheat germ (Triticum vulgare) oil

Essential Oils:

• 3 drops of sea buckthorn (Hippophae rhamnoides)
• 3 drops of helichrysum (Helichrysum italicum) OR 3 drops of German chamomile (Matricaria recutita)
• 3 drops of geranium (Pelargonium graveolens)
• Optional: For a lotion, add 1/2 cup of melted Shea butter (Butyrospermum parkii)

Instructions for Making: Mix the tincture ingredients from in a large glass jar. Shake three times a day for two weeks, setting in the sun during the day. Strain all plant parts from the alcohol using cheesecloth or a coffee filter. The remaining alcohol is the tincture.

The next step is to mix the oil or lotion ingredients together with the tincture you’ve made. Apply 1/4 teaspoon to the skin up to three times day. This recipe is great for burns, wounds, and dry skin.  If you want to make a thick creamy lotion, add 1/2 cup of melted Shea butter to the mix and mix it with a blender on high for five minutes.

Floral Relaxation Bath Blend

Ingredients:

• 8 oz. of sea salt
• 2 oz. jojoba (Simmondsia chinensis)

Essential Oils:

• 1 drop of ylang ylang(Cananga odorata)
• 1 drop of lavender (Lavandula angustifolia)
• 1 drop of bergamot (Citrus bergamia)

Instructions for Making: Mix together the essential oils with the carrier oil and add to the sea salt. Pour about half a cup of the blend into a warm bath and relax.

Immortelle Face Serum

Ingredients:

• 2 oz. calendula infused jojoba oil (Calendula officinalis and Simmondsia chinensis)
• 2 Tbsp. of rose hip (Rosa canina)
• 2 Tbsp. of wheat germ (Triticum vulgare)

Essential Oils:

• 10 drops of helichrysum (Helichrysum italicum)
• 2 drops of cistus (Hippophae rhamnoides)

Instructions for Making: First, make the calendula infused jojoba oil (or you can also use jojoba oil on its own).  To make the calendula infused jojoba oil: Add 16 oz. of clean, non-wet, organically grown blooms to 48 ounces of sweet almond and/or jojoba oil in a glass jar.  Set on a window sill in the sun for up to one month. Strain all of the flower parts from the oil using a coffee filter or cheesecloth and funnel. Store the infused oil in an amber glass container, and use within six months.

Mix the rest of the ingredients and essential oils with the calendula infused jojoba oil and store in a dark glass container with a dropper. Apply a dime size of oil to the face up to two times a day. Discontinue use if irritation occurs.

References

1. Bowles, E. J. (2003). Chemistry of aromatherapeutic oils. Allen & Unwin.
2. Clarke, S. (2008).Essential chemistry for aromatherapy. Elsevier Health Sciences.
3. Tisserand, R. & Young, R. (2014).  Essential Oil Safety, Second Edition. Edinburgh: Churchill Livingstone Elsevier.
4.  Bachewar, N. P., Thawani, V. R., Mali, S. N., Gharpure, K. J., Shingade, V. P., & Dakhale, G. N. (2009). Comparison of safety, efficacy, and cost effectiveness of benzyl benzoate, permethrin, and ivermectin in patients of scabies. Indian journal of pharmacology, 41(1), 9.
5. Hay, R. J., Steer, A. C., Engelman, D., & Walton, S. (2012). Scabies in the developing world—its prevalence, complications, and management. Clinical Microbiology and Infection, 18(4), 313-323.
6. Hayden, M. L., Rose, G., Diduch, K. B., Domson, P., Chapman, M. D., Heymann, P. W., & Platts-Mills, T. A. (1992). Benzyl benzoate moist powder: investigation of acarical activity in cultures and reduction of dust mite allergens in carpets. Journal of allergy and clinical immunology, 89(2), 536-545.
7. McDonald, L. G., & Tovey, E. (1993). The effectiveness of benzyl benzoate and some essential plant oils as laundry additives for killing house dust mites. Journal of allergy and clinical immunology, 92(5), 771-772.
8. Mühlbauer, R. C., Lozano, A., Palacio, S., Reinli, A., & Felix, R. (2003). Common herbs, essential oils, and monoterpenes potently modulate bone metabolism. Bone, 32(4), 372-380.
9. Buchbauer, G., Jäger, W., Jirovetz, L., Meyer, F., & Dietrich, H. (1992). Effects of valerian root oil, borneol, isoborneol, bornyl acetate and isobornyl acetate on the motility of laboratory animals (mice) after inhalation.
10. Fang, H. J., Su, X. L., Liu, H. Y., Chen, Y. H., & Ni, J. H. (1988). [Studies on the chemical components and anti-tumour action of the volatile oils from Pelargonium graveoleus]. Yao xue bao= Acta pharmaceutica Sinica, 24(5), 366-371.
11. Lee, K. G., & Shibamoto, T. (2001). Antioxidant property of aroma extract isolated from clove buds [Syzygium aromaticum (L.) Merr. et Perry]. Food Chemistry, 74(4), 443-448.
12. Friedman, M., Henika, P. R., & Mandrell, R. E. (2002). Bactericidal activities of plant essential oils and some of their isolated constituents against Campylobacter jejuni, Escherichia coli, Listeria monocytogenes, and Salmonella enterica. Journal of Food Protection®, 65(10), 1545-1560.
13. Dorman, H. J. D., & Deans, S. G. (2000). Antimicrobial agents from plants: antibacterial activity of plant volatile oils. Journal of applied microbiology, 88(2), 308-316.
14. Rombolà, L., Amantea, D., Russo, R., Adornetto, A., Berliocchi, L., Tridico, L., & Morrone, L. A. (2016). Rational Basis for the Use of Bergamot Essential Oil in Complementary Medicine to Treat Chronic Pain. Mini reviews in medicinal chemistry, 16(9), 721-728.
15. Ghelardini, C., Galeotti, N., Salvatore, G., & Mazzanti, G. (1999). Local anaesthetic activity of the essential oil of Lavandula angustifolia. Planta medica, 65(08), 700-703.
16. de Sousa, D. P., Júnior, G. A., Andrade, L. N., & Batista, J. S. (2011). Spasmolytic activity of chiral monoterpene esters. Records of Natural Products, 5(2), 117.
17. Peana, A. T., D’Aquila, P. S., Panin, F., Serra, G., Pippia, P., & Moretti, M. D. L. (2002). Anti-inflammatory activity of linalool and linalyl acetate constituents of essential oils. Phytomedicine, 9(8), 721-726.
18. Russo, R., Ciociaro, A., Berliocchi, L., Cassiano, M. G. V., Rombolà, L., Ragusa, S., & Corasaniti, M. T. (2013). Implication of limonene and linalyl acetate in cytotoxicity induced by bergamot essential oil in human neuroblastoma cells. Fitoterapia, 89, 48-57.
19. Soković, M., Glamočlija, J., Marin, P. D., Brkić, D., & van Griensven, L. J. (2010). Antibacterial effects of the essential oils of commonly consumed medicinal herbs using an in vitro model. Molecules, 15(11), 7532-7546.
20. Pitarokili, D., Couladis, M., Petsikos-Panayotarou, N., & Tzakou, O. (2002). Composition and antifungal activity on soil-borne pathogens of the essential oil of Salvia sclarea from Greece. Journal of agricultural and food chemistry, 50(23), 6688-6691.
21. Takahashi, M., Satou, T., Ohashi, M., Hayashi, S., Sadamoto, K., & Koike, K. (2011). Interspecies comparison of chemical composition and anxiolytic-like effects of lavender oils upon inhalation. Natural product communications, 6(11), 1769-1774.
22. Buchbauer, G., Jirovetz, L., Jáger, W., Plank, C., & Dietrich, H. (1993). Fragrance compounds and essential oils with sedative effects upon inhalation. Journal of pharmaceutical sciences, 82(6), 660-664.
23. Voinchet, V., & Giraud-Robert, A. M. (2007). Utilisation de l’huile essentielle d’hélichryse italienne et de l’huile végétale de rose musquée après intervention de chirurgie plastique réparatrice et esthétique. Phytothérapie, 5(2), 67-72.
24. Tundis, R., Statti, G. A., Conforti, F., Bianchi, A., Agrimonti, C., Sacchetti, G., & Poli, F. (2005). Influence of environmental factors on composition of volatile constituents and biological activity of Helichrysum italicum (Roth) Don (Asteraceae). Natural product research, 19(4), 379-387.

4/4/18

This categorized compilation of research articles does not necessarily imply that there are adequate results to demonstrate safe and/or effective human use. These statements are not meant to diagnose, treat, or cure any diseases. The information at this page has not been evaluated by the Food and Drug Administration. Consult a Doctor before using herbs and essential oils if you have medical conditions, are taking medications, or have questions.