Toxic essential oils

There is a vogue for many scientifically nonqualified aromatherapists to practice clinical aromatherapy, in which they prescribe the internal usage of essential oils. Internal prescribing involves oral, rectal, and vaginal intake however, the use of tampons soaked in various potentially toxic essential oils, such as the various tea tree oils, with variable biological potential could have a possible harmful effect on the delicate internal mucosal membranes. The possibility of misdiagnosis of a urogenital condition by medically unqualified aromatherapists or by the patients themselves could also result in serious consequences. 

Ledol and palustrol are two aromadendrane derivatives in the essential oil from Labrador tea Ledum palustre). This oil causes vomiting, gastroenteritis, and excitation in man but is also toxic for animals [9]. Recently, fraganol and fraganyl acetate, rare mmioterpenes, were described as toxic essential oil components in Achillea umbellata [75]. 

Radulovic NS, Dekic MS, Randelovic PJ, Stojanovic NM, Zarubica AR, Stojanovic-Radic ZZ (2012) Toxic essential oils anxiolytic, antinociceptive and antimicrobial properties of the yarrow Achillea umbellata Sibth. Et Sm (Asteraceae) volatiles. Food Chem Toxicol 50 2013-2026. doi 10.1016/j.fct2012.03.047... 

Volatile mustard oil (or allyl isothiocyanate) is an extremely powerful irritant and produces blisters on the skin. It is also tear producing (lachrymatory) and has counterirritant properties when greatly diluted (e.g., 1 in 50). It should not be tasted or inhaled when undiluted. It is one of the most toxic essential oils (gosselin jiangsu martindale). ... 

Essential oils are known to have detrimental effects on plants. The inhibitory components have not been identified, but both alde-hydic (benzol-, citrol-, cinnamal-aldehyde) and phenolic (thymol, carvacol, apiol, safrol) constituents are suspected. Muller et al. (104) demonstrated that volatile toxic materials localized in the leaves of Salvia leucophylla, Salvia apiana, and Arthemisia californica inhibited the root growth of cucumber and oat seedlings. They speculated that in the field, toxic substances from the leaves of these plants might be deposited in dew droplets on adjacent annual plants. In a subsequent paper, Muller and Muller (105) reported that the leaves of S. leucophylla contained several volatile terpenes, and growth inhibition was attributed to camphor and cineole. 

In view of the development in synthetic toxic agents, described in this paper, this phase of the project has become somewhat less important. It was equally essential then, however, that some oil diluent should be available, so that toxicities of oil-soluble, water-insoluble substances could be studied. 

Guba R (2000) Toxicity myths essential oils and their carcinogenic potential. In Essential Oils and Cancer. Proceedings of the 4th Wholistic Aromatherapy Conference, San Francisco... 

Aspidium falcatum Sw. (Syn. Dryopteris crassirhizoma) Guan Zhong (Wood fem) (whole plant) Filicic acid, tannins, essential oil.49 This herb is slightly toxic. Anthelmintic, hemostatic, antidote. 

Atractylis chinensis DC A. lancea Thunb. A. lyrata Sieb. et Zucc. A. ovata Thunb. Zhang Shu (root) Essential oils, atractylone, hinesol, atractylodine, atractylol, beta-eudesmol, diacetyl-atractylodiol33 This herb is toxic. Lower blood sugar, sedative. 

Rabdosia rubescens Dong Ling Cao (aerial part) Rubescensine B, oridonin, tannic acid, ponicidine, essential oils.33 This herb is toxic. Treat esophageal cancer, malignant cancer. 

A recent survey about essential oils and their pure constituents used to control Varroa jacobsoni, contained three interesting tables that reported the toxicity of essential oils for V. jacobsoni and Apis mellifera after 24, 48 and 72 hours in a topical application and in an evaporation test, and the effects of essential oils on behavior and reproduction of V jacobsoni and on the bee brood [63]. The most interesting oils were those of cinnamon and clove, with 100% mite mortality after 24 h and no significant toxicity on honey bees. Furthermore, clove essential oil produced small brood mortality, and it was an inhibitor of mite reproduction. Other effective oils were anise, fennel, lavender, rosemary and wintergreen, which killed 100% mites after 48-72 hours. On the contrary, the oils obtained from garlic, onion, oregano and thyme, were found to be very toxic for honey bees. Among pure constituents, camphor, linalool, linalyl acetate and pinene resulted small brood mortality and inhibited mite reproduction. 

Summarizing, the use of natural products as miticides in apiculture, with the exception of some substances, is not widespread. In extensive laboratory tests many compounds showed significant acaricidal properties. However, very few of them have proven to be effective when applied in field trials. Considerable variations in local environmental and colony conditions can affect efficacy. In case of mixtures, such as essential oils, the difficulty in obtaining standardized compounds also affects treatment predictability. Nevertheless, identifying new acaricide compounds with low toxicity to honey bees is fundamental for providing candidate compounds for field trials. Furthermore, the development of... 

All the tested substances were placed in 6 cm airtight petri dishes and resulted toxic for the mites, that were immobilized within 15 min to 1 h. Linalyl acetate and camphor were active only at the highest doses (6 xl/dish), with 96.7% and 30.0% mortality, respectively. The essential oil showed 98.3% mortality at 0.50 pi (100% at 2 pi), while linalool was the most effective compound (96.7% at 0.25 pi, 100% at 0.50 pi). In further research on the essential oil of L. angustifolia and its constituent linalool, we evaluated the activity of this essential oil on the same parasite using inhalation, rather than direct contact between mites and compounds... 

Mace - [REPELLENTS] (Vol 21) - [FLAVORS AND SPICES -SPICES] (Vol 11) - [FLAVORS AND SPICES -SPICES] (Vol 11) -essential oil equivalent [FLAVORS AND SPICES - FLAVORS] (Vol 11) -food toxicants m [FOOD TOXICANTS, NATURALLY OCCURRING] (Vol 11)... 

Fatty acid esters would be predicted to have little irritation or toxic effects. Ex vivo permeability studies conducted in porcine buccal mucosa showed significant permeation enhancement of an enkephalin from liquid crystalline phases of glycerine monooleate [32]. These were reported to enhance peptide absorption by a cotransport mechanism. Diethylene glycol monoethyl ether was reported to enhance the permeation of essential oil components of Salvia desoleana through porcine buccal mucosa from a topical microemulsion gel formulation [33]. Some sucrose fatty acid esters, namely, sucrose laurate, sucrose oleate, sucrose palmitate, and sucrose stearate, were investigated on the permeation of lidocaine hydrochloride [34], with 1.5% w/v sucrose laurate showing a 22-fold increase in the enhancement ratio. 

---