Pharmacology of Natural Volatiles and Essential Oils in Food, Therapy, and Disease Prophylaxis

Abstract

This commentary critically examines the modern paradigm of natural volatiles in ‘medical aromatherapy’, first by explaining the semantics of natural volatiles in health, then by addressing chemophenetic challenges to authenticity or reproducibility, and finally by elaborating on pharmacokinetic and pharmacodynamic processes in food, therapy, and disease prophylaxis. Research over the last 50 years has generated substantial knowledge of the chemical diversity of volatiles, and their strengths and weaknesses as antimicrobial agents. However, due to modest in vitro outcomes, the emphasis has shifted toward the ability to synergise or potentiate non-volatile natural or pharmaceutical drugs, and to modulate gene expression by binding to the lipophilic domain of mammalian cell receptors. Because essential oils and natural volatiles are small and lipophilic, they demonstrate high skin penetrating abilities when suitably encapsulated, or if derived from a dietary item they bioaccumulate in fatty tissues in the body. In the skin or body, they may synergise or drive de novo therapeutic outcomes that range from anti-inflammatory effects through to insulin sensitisation, dermal rejuvenation, keratinocyte migration, upregulation of hair follicle bulb stem cells or complementation of anti-cancer therapies. Taking all this into consideration, volatile organic compounds should be examined as candidates for prophylaxis of cardiovascular disease. Considering the modern understanding of biology, the science of natural volatiles may need to be revisited in the context of health and nutrition.

Fundamental Chemistry of Essential Oils and Volatile Organic Compounds, Methods of Analysis and Authentication

“…Essential oils and natural volatiles are one of industry’s most successful commodities, since they are used as flavours [ 1 ], in lotions or shampoos as fragrances and for skin and hair rejuvenation [ 2 , 3 ], as perfumes, in candles, soaps, liquids that sterilise, and in conventional or medical aromatherapy [ 4 ]. This widespread demand has meant that significant profits are to be made by providing essential oils or their components at the most competitive price.…”

“…Furthermore, aromatic plants are sometimes extracted into fixed oils, then advertised as an ‘essential oil’, which implies a higher quality product [ 5 ]. Fortunately, consumers are becoming more aware of the difference between an essential oil and an extract, concrete, absolute or enfleurage perfume [ 4 , 8 ].…”

Purely Australian Essential Oils Past and Present: Chemical Diversity, Authenticity, Bioactivity, and Commercial Value

“…Antimicrobial outcomes are also influenced by synergistic effects between volatile organic compounds and fixed components in extracts [15,16], the concentrations are still many orders of magnitude above antibiotics [17]. Furthermore, antimicrobial outcomes are augmented when essential oils are delivered as vapours in warm air [18,19], but again, the inhibitory concentrations are only significant in the context of household usage, topical antiseptic use or in ethnopharmacology.…”

“…Information is usually restricted to toxicity data from effects observed over the span of hundreds of years against grazing stock. Information of antimicrobial data is also readily available because it is generated quite easily in standard university labs [14,17].…”

“…There is a wide selection of possible applications for essential oils in aesthetics where antimicrobial activity is needed. Although essential oils are not considered a primary treatment for dermatological infections, they are preventative and can be used like a disinfectant [17]. Essential oils are better for antibacterial and antifungal applications than pure alcohol, because alcohol is quickly evaporated, whereas the essential oil components absorb into the dermis and confer protection for longer.…”