Therapeutic Potential of Essential Oils against SARS-CoV-2 Infection

Essential oils consist of a complex mixture of diverse, lipophilic and volatile phytochemical constituents associated with a wide range of ethnopharmacological applications. Apart from their antibacterial, antifungal and antiparasitic actions, essential oils have also exhibited antiviral effects against the influenza virus, human immunodeficiency virus, avian influenza virus and yellow fever virus. Essential oils exert non-specific virucidal and anti-inflammatory effects, and are readily exhaled from the lungs due to their smaller molecular weight and volatile nature. In addition to the useful pharmacological actions of individual oils, aromatherapy in the form of blends or combinations of essential oils has also demonstrated additive or synergistic effects in alleviating the typical manifestations of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Consequently, essential oils represent an alternative and promising source for the development of clinically effective drugs against SARS-CoV-2 infection. Besides, essential oils and their pharmacologically-active compounds can be used as an adjunct to existing drugs for add-on therapy against microbial infections, particularly those affecting the respiratory tract. Preliminary in vitro evidence regarding the potential efficacy of essential oils against SARS-CoV-2 requires comprehensive validation through in silico and in vivo studies. Further studies are recommended to explore the antiviral mechanism of essential oils and their pharmacologically-active products during various stages of viral infection. This chapter describes the major phytochemical ingredients, antiviral mechanisms and pharmacotherapeutic considerations of essential oils in the context of SARS-CoV-2 infection.