By Marco Valussi
No. There is a lot of confusion about the term "essential oil", which is worth dispersing.
Some authors have written that essential oils are called like that because they perform "essential" functions in plants, some say that essential oils are akin to the vital energy of a plant, or that they play the same role in plants as blood does in animals. Others say that they represent the "essence", the totum, of the plant, that in the essential oils we find represented all the complexity of a plant. Finally, other authors would state than that essential oils perform "essential" functions in our body.
It must be stressed that the genesis of the name "essential oil" is fairly clear, probably derived from the alchemical environment and from the idea that alchemists had that distillation was a process of "purifying the coarse from the thin". The belief was that by means of this process alchemists could obtain the "fifth essence", the "incorruptible element". That is why the "essential" term denotes, in the reading of European medieval alchemists, the incorruptible and foundational nature of what is obtained from distillation (which, we should briefly state here, at the beginning were not essential oils per se, but aromatic waters, which were deemed more subtle).
Having said this, what scientific bases have the explanations offered by some authors in aromatherapy? Let's see:
1. Essential oil performs "essential" functions in plants, which is essential for the survival of plants.
If, for essential function, we mean that without the essential oil the plant cannot survive, we already know that this is not true, both in the sense that there are plants that do not produce essential oils (non aromatic plants) and yet survive perfectly well in their environment, and in the strictest sense that even aromatic plants survive without essential oils. This can be demonstrated in both indirect and direct ways. Our knowledge of the role of essential oils in plants tells us that they are very important as tools of attraction, defense and ecological mediation between plant and biotic and abiotic environment, but that they are not indispensable for the survival of the plant itself, not in the sense in which chlorophyll or starch or cellulose are. A plant cannot survive, it cannot exist without chlorophyll to capture and transform radiant energy, without starch to store the chemical energy derived from sunlight, or without cellulose to give solidity to its structure. An aromatic plant deprived of essential oils survives worse than others, and is less fit, less able to cope with periods of crisis, but it still can survive.
If we hold that essential oil are not "essential" to the plant, it is clear that they cannot be described as the vital energy of a plant, such as the plant's blood. Besides, this would leave no explanation as to how non aromatic plants would survive without essential oils, since they would be devoid of vital, "blood" energy. In addition, the idea that essential oils may "circulate" in the plant, perhaps through the lymphatic channels, is completely unfounded. Essential oils are extremely concentrated and active substances, and if they come into direct contact with the plant tissues, they will damage them very quickly. In fact, they are stored in special structures, pockets, glandular hairs, canals, and so on, which keep them well separated from other tissues.
Of course this does not mean that essential oils do not play very important roles, but that is another matter
2. Essential oils represent the totum of the plant, they enclose all the complexity of the plant.
This we know very well not to be true, if we just go back a minute to the process we use to get the essential oils. It is clear that they are a very specific and limited fraction of the whole complexity of the plant (phytocomplex). They only contain molecules that are volatile and which are liposoluble, usually a very small fraction of the phytochemical complex of the plant. Any alcoholic tincture or even a herbal tea is more complex in the chemical sense than an essential oil, because they contain a wider range of molecules. Of course, essential oils represent a very salient fraction from the sensual, organoleptic and symbolic point of view, but this has to do with human culture and biology, not with the plant's.
3. Essential oils perform "essential" functions in our body.
This is certainly not true if by essential we mean necessary for life. Human beings have survived and survive without any problems without essential oils. Humans did not use essential oils for most of their history. It is true that aromatic plants (which contain essential oils) have accompanied man for a long time. But of course, as important as they were, they were not necessary for human life.