Natural has been the rage of the flavor and fragrance industry over the last decade. However, in retrospect, one might well refer to the 20th century as the era of synthetic organic chemicals. Thus, at the beginning of the new millennium, it is surprising to find that the supply of a number of common, commercially available aroma chemicals remains largely or solely of natural in origin (i.e. eugenol, l-menthol, menthone and eucalyptol). Eucalyptol shares with eugenol the rare distinction of being one of two large-volume aroma chemicals whose supply is totally natural. No synthetic counterpart of these two materials is offered commercially. The basis for this reality is economic. Mother Nature can produce these materials far more economically than can the chemist.
Eucalyptol’s basic impression is medicinal-camphoraeous. Small amounts of Eucalyptus fractions or Eucalyptol can twist a floral material, such as linalool or Aprol® 100 into a lavender. The term “medicinal” is used as a nebulous descriptive modifier for a number of aroma chemicals whose overall organoleptic profile have little in common; camphor, carvcarol, methyl salicylate, thymol, eucalyptol. This relatively negative term is a result of their use as disinfectants in hospitals and “rooms of the infirm”. The six to seven percent eucalyptol content of the pine oil these cleaners contain dominates the impression of these “disinfectants”. Many of these products have a strong, ethereal impact and their use can invoke unpleasant memories; hence the negative reaction. Their use as bacteriostats and bacteriocides grew out of folk medicine and their efficacy has been confirmed through modern research. Often the Table 2. Contents of Vicks Vaporub (1989) Cedar leaf Oil 0.75% Camphor 4.7-5% Eucalyptus Oil 1.2-1.5% Menthol 2.6-2.8% Nutmeg Oil 0.75% Thymol 0.25% Turpentine 5% combination of a number of essential oils displayss synergism in its bacteriostatic and bacteriocidal activity. A side development has been their use in aromatherapy, which itself is little more than an extension of folk medicine. That the term “medicinal” is used to describe eucalyptol and these other items should not be surprising, because their major applications involve medicines. These include cough drops and syrup, aromatic balms, tiger balm, and mouthwash. The mixtures used to create these medicines show an interesting similarity around the globe. Even in today’s guides on aromatherapy, we find eucalyptol and eucalyptus globulus listed for antiseptic and rubefacient usage. A good representative for the type of mixture found in this group is Vicks Vaporub (Table 2).
This medicinal view of eucalyptol remains valid, despite the latest craze for eucalyptus-menthol candies. Possibly the most perplexing facet of this subject is the general negative impression the public has of the combination of menthol and eucalyptol as a flavor. Angelich reported in an article that older North American consumers list the menthol- eucalyptus flavor in hard candies in the five mostdisliked flavor categories8 A 1992 Wall Street Journal article reported that the major brands of mouthwash, which contain eucalyptol, are all losing market share.