Are essential oils the real solution to respiratory viruses?

Essential oils possess a wide-spectrum of antibacterial, antifungal anti-viral activity and have also been shown to inhibit the growth of drug-resistant microbial strains which are difficult to be treated through conventional means. Many essential oils have antiviral activity and human and animal viruses while several essential oils have antiviral activities against many RNA and DNA viruses, such as type 1 and type 2 herpes simplex virus (HSV-1 and HSV-2), dengue virus type 2, influenza virusadeno virus type 3, poliovirus, Junin virus, and coxsackievirus B1 1,2. As well as an inhibitory effects on adenovirus and mumps virus 3.


Currently there are approximately 3000 established essential oils and are the complex mixtures of natural compounds of about 20–60 constituents in varying quantities. The special biological properties and fragrance of essential oils are due to Terpenes and phenylpropanoids which are major components of essential oils and have antiviral, fungal and bacterial properties. As a result of their complex mixture of ingredients they can act synergistically to have widespread benefits in controlling viruses and overall health. For example, the essential oils derived from medicinal aromatic plants like Peppermint (Mentha piperita), thyme (Thymus vulgaris), fennel (Foeniculum vulgare), are reported to be effective against Gram-negative and Gram-positive bacteria viruses, fungi and yeast as well as immune boosting, anti-inflammatory and antioxidant effects. 

While modern pharmaceutical medicine is wildly scathing of most forms of complimentary medicine, Star anise (Illicium verum), which is widely known for its antiviral effects is also the source of the precursor molecule, shikimic acid, which is used in the manufacture of oseltamivir (Tamiflu®), an antiviral medication for influenza A and influenza B. Besides, shikimic acid several other molecules with numerous biological benefits including the antiviral effects have been reported from the same plant. Except the antiviral potential, star anise possesses a number of other potentials such as antioxidant, antimicrobial, antifungal, anthelmintic, insecticidal, secretolytic, antinociceptive, anti-inflammatory, gastroprotective, sedative properties, expectorant and spasmolytic, and estrogenic effects 4. Imagine having a drug with so many benefits.


One study demonstrated anti-influenza activity in 11 essential oils tested, with marjoram, clary sage and anise essential oils being the most effective at reducing visible cytopathic effects of the A/WS/33 virus. All 3 oils contained linalool, suggesting that this may have anti-influenza activity 5. The volatile oil from Cynanchum stauntonii (a Chinese herb) possessed direct inhibitory activity against influenza virus 6 and the essential oils of Marjoram (Thymus mastichina L.), clary sage (Salvia sclarea L.) and anise (Pimpinella anisum L.) showed anti-influenza A/WS/33 activity. The EOs of Atractylodes macrocephala a Chinese herb called Bai zhu exhibited antiviral effect on viruses H3N2 as well as anti-inflammatory activity 7.

Melaleuca alternifolia tea tree oil (TTO) has been shown to have antibacterial, antifungal, and antiviral activities, and while most of the biological properties can be ascribed to terpinen-4-ol the antimicrobial activity of TTO results from complex interaction among different components 8. The effect of Zataria multiflora (Shirazi thyme” and “Iranian thyme) essential oil reduced viral replication in both the intestine and trachea of H9N2 influenza infected animals, that led to milder clinical symptoms and better performance 9

Germacrone is one of the major components of the essential oils extracted from Rhizoma Curcuma (turmeric and other gingeraceae plants) has antitumor, anticancer, antiviral, antibacterial, and anti-inflammatory activity. In addition, germacrone inhibits influenza virus (IAV), Porcine parvovirus (PPV), Feline calicivirus (FCV), and Porcine reproductive and respiratory syndrome virus (PRRSV) replication 10,11,12,13. Germacrone also has inhibitory effects on H1N1, H3N2 influenza viruses, and Influenza B viruses in the early stages of the viral cycle and can protect mice from fatal infection 11 and was able to effectively inhibit viral replication in a dose-dependent manner in vitro in the early phase of the viral replication cycle. The researchers concluded that germacrone could be used as an efficient microbicide or immunomodulatory agent in the control of the emerging variant PRV (also known as suid herpesvirus-1) 14. In another study, germacrone was found to inhibit influenza virus replication and showed antiviral activity against the H1N1 and H3N2 influenza A viruses and the influenza B virus in a dose-dependent manner. Germacrone was found to exhibit an inhibitory effect on both the attachment/entry step and the early stages of the viral replication cycle. Germacrone also exhibited an effective protection of mice from lethal infection and reduced the virus burden in the lung 15

Eugenol, which is another ingredient found in high concentrations in multiple essential oils, and has shown antiviral activity against feline calicivirus, tomato yellow leaf curl virus, Influenza A virus, Herpes Simplex virus type 1 and 2, and four airborne viruses 16

It is without doubt that essential oils possess many health benefits which go beyond just a single illness. The real value of essential oils is that they do not just have extensive anti respiratory virus effects, and the pharmaceutical companies know this, but they also have widespread antiviral effects on virtually every virus they have been tested on. In addition, they have anti-bacterial and anti-fungal effects which can dramatically reduce the risk of co-infection of these pathogens and immune modulating effects, gut microbiome boosting effects and are anti-inflammatory and antioxidant to reduce the damage in case a person is infected and support their health. 


Note that I tried to keep this article with a focus on respiratory viruses, there are however as far as I can see at first glance around 200 studies on viruses and essential oils with most focusing on herpes and HIV. Nor is this a comprehensive review of all the literature on this topic.


Disclaimer

This information is not meant to be medical advice and to the best of my knowledge it is true unlike most of the scaremongering around the corona virus. However, when using essential oils please be sure they are pure therapeutic grade essential oils without additional additives, there are different ways they can be applied and they may have some contraindications with some health conditions. Always consult a health professional.


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