Essential oil profiles

13


Essential oil profiles




Notes


This chapter consists of 400 safety profiles on essential oils, absolutes and resinoids. In cases where there are no toxicity data for an essential oil, but there are for its major constituents we have indicated the likely safety of the oil on this basis. Because of interactions between constituents, toxicity in the whole essential oil might be either greater or lesser than would be expected from the concentration of a particular constituent or constituents. However, in the absence of data on an essential oil, we feel that it is more useful to extrapolate constituent data than to take the view that nothing is known.


The aromatic raw materials profiled were selected because they are commercially available. We have no hard data for annual production, but if at least one supplier in the West is offering the material for sale on the open market, we have attempted to include it. However this has proved a daunting task, and no doubt there are omissions. A few profiles are included of essential oils that are not commercially available (such as plectranthus) because information about their toxicity sheds light on chemically similar, commercially available oils.


We have not attempted to restrict the materials covered in this section to those currently or most popularly used in aromatherapy, since there is no definitive list. Increasingly, practitioners, product formulators and private individuals seek out unusual aromatic materials.



Information given in the profiles


Common name: The essential oils are indexed under common name, not botanical name. This causes difficulties where there is no common name, or where common names are not widely known or used. However, it makes for ease of use by readers not familiar with botanical names, and more importantly, it facilitates the grouping of chemically and toxicologically similar essential oils, such as the various pennyroyal or sassafras oils, into one profile.


In some instances, such as cedarwood, chamomile, citronella, fir needle, lemongrass, lime and valerian, a different place of origin is consistent with a different species. For example, Mexican type lime, Citrus x aurantifolia Christm., and Persian type lime, Citrus x latifolia Tanaka. In such cases, the species was originally cultivated in that country or region, but is now also grown in other geographical locations. Therefore ‘Mexican’ lime may not come from Mexico.


Botanical name: We have tried to give preference to the most currently accepted botanical name and synonyms. When essential oils derive from more than one botanical source we have attempted to include all origins.


Family: Where there are alternative names for the same family, these are given in brackets.


Source: The part of the plant from which the essential oil, absolute or resinoid is distilled, expressed or solvent extracted.


Key constituents: Where they are known, constituents are listed in descending order of percentage down to the level of 1%, or lower for known toxic constituents such as carcinogens or phototoxins. We have not included most constituents occurring at less than 1% in the interests of space, and because these are likely to have little toxicological relevance. The percentages are given as ranges where possible and where appropriate. These ranges represent the types of essential oil commercially available. Occasionally we have given compositional data for oils of the same species but from different countries of origin, for example, ginger, patchouli and sweet orange. In these instances differences in composition are of little toxicological significance, but the data were included because they were readily available. In other cases, such as mace, nutmeg and tarragon, such differences are toxicologically significant.


In some instances, different chemotypes are described within a single profile (rosemary, wormwood) and in others, where the differences are more toxicologically significant, each chemotype has its own profile (basil, ho leaf, niaouli, thyme).


The abbreviation ‘tr’ denotes trace. Where isomeric compounds occur in an essential oil the quantities are often inversely proportional. For example, in Thymus serpyllum thymol/carvacrol CT, we find carvacrol 15.6–27.8% and thymol 16.7–25.9%. The highest likely amount of both compounds in a single oil is not 53.7% (27.8% + 25.9%), but 44.5% (e.g., 27.8% + 16.7%). In many cases, specific isomers of constituents were not reported, and unless stated, they are unspecified.


Hazards: Brief details are given here of why the substance may be hazardous. Note that ‘hazard’ denotes a potential for risk, not necessarily an actual risk.


Contraindications: When the oil should be avoided. The method of administration is also stated. Oral contraindications apply to the oral administration of essential oils as used in aromatic medicine. Oral contraindications do not apply to the use of essential oils in any other context, such as in foods, fragrances, personal care products or by inhalation.


Cautions: These are potential hazards that do not warrant contraindications, either because the evidence is flimsy or because the hazard is not especially worrying.


Maximum adult daily oral dose: Most of these values are extrapolated from our own safety guidelines. They are based on an average human weight of 70 kg (154 lb).


Maximum dermal use level: For many of the profiled oils a recommended maximum level for external use is given. This is often based on already established guidelines, and is intended to avoid skin reactions, carcinogenesis or other forms of toxicity. But, see EU allergens legislation and IFRA guidelines below. The maximum dermal use level is based on the maximum possible concentration in the essential oil of the toxic constituent(s). Therefore essential oils with lower concentrations of toxic constituents (in some cases zero) may require less restriction, or even no restriction.


Toxic constituents are assessed collectively, according to their action. So the effect of all known carcinogens is taken into account in a single essential oil, but this is not combined with the action of neurotoxins or allergens. In a few cases the maximum dermal use level depends on which type of toxic effect is considered, and in those cases we recommend the lowest concentration.


For carcinogens, we include a box showing the regulations that would be applied (a) in the EU, (b) by IFRA, and (c) our own recommendation, according to the maximum level of carcinogenic constituents shown in the profile. Note that regulations change on a regular basis, and the ones shown may not be current. In the case of phototoxicity, maximum use levels can be exceeded if care is taken to avoid exposing the skin to UV rays for 12–18 hours after application. Note that, unless there is a separate guideline for pregnancy, maximum use levels include safety in pregnancy.


Our safety advice: The advice given in this section is from the authors of this book. Our own safety guidelines for specific constituents are often applied. We decided to do this because we felt strongly that regulatory guidelines are sometimes over- or under-precautionary. In addition to these specific guidelines, there are general ones that apply to children (Table 4.5).


Regulatory guidelines: This is discussed below, in a separate section.


Organ-specific effects: This section varies according to the information available. For example, if there is nothing on hepatotoxicity, then there is no section on hepatotoxicity.


Adverse skin reactions: For skin irritation in animals, the undiluted test materials are applied to the backs of hairless mice, to intact or abraded rabbit skin, or to other test animals. In humans irritation is tested by a 48-hour closed-patch test in 25–30 volunteers at the dilution given. Sensitization is tested by a maximation test, usually on 20–30 volunteers at the dilution given. Phototoxicity testing is generally carried out on pigs. In this particular test a strong correspondance has been established between the reaction of pig skin and human skin.


Systemic effects: As with organ-specific effects, the sub-sections included here vary according to the available information.


Acute toxicity: Details are given of the results of acute oral or dermal toxicity tests or, where relevant, of any known toxic constituents. In most cases more detail on the toxic constituents will be found in Constituent profiles, Chapter 14.


Carcinogenic/anticarcinogenic potential: Any positive or negative data are given here for genotoxicity and carcinogenicity.


Drug interactions: Much of the information included here is unique to this text. For space reasons, we could not list each drug involved, and some cross-referencing will need to be done with Appendix B.


Comments: Any further useful information or observations are given here.


In a few profiles, other headings such as hepatotoxicity, neurotoxicity and subacute toxicity are included.



Regulatory guidelines


Details are given here of safety guidelines from organizations concerned with safety.






Adjusting safe doses and concentrations



The amount applied


Our maximum dermal use levels are based on 30 mL, which we estimate to be the maximum amount of a single product application in one day. For local skin reactions (irritation, sensitization and phototoxicity) these maximum percentages should be adhered to, even if a smaller quantity of total product is used. Skin reactions depend on the concentration of toxic substance per square cm of skin, so even a small amount applied to a small area of skin can be problematic. For more general and systemic types of toxicity (carcinogenicity, hepatotoxicity, neurotoxicity, teratogenicity, drug interactions), when a smaller amount of product is applied topically, the maximum % can be increased proportionally, because toxicity is dependent on total dose, not dermal concentration. For example, the maximum dermal use level for Dalmatian sage oil is 0.4%. But if only 5 mL (approximately 5 g) of a product containing this oil is used, the maximum concentration could be increased to 2.4% (30/5 × 0.4). These calculations apply equally to leave-on and wash-off types of product. For infants and children, see (Ch. 4, p. 47).




Phototoxic oils


If several phototoxic oils are used together, the risk is assumed to increase proportionally, as outlined above. For instance, bergamot and cumin oils both have maximum dermal use levels of 0.4%. If both are used in a product in equal proportions, the maximum safe percentage will be 0.2% for each, not 0.4% for each. Phototoxicity cautions apply to leave-on products and to steam inhalation, but they do not apply to wash-off products or to ambient inhalation. When using deterpenated (folded) citrus fruit oils, we recommend checking with the supplier for phototoxicity risk. Deterpenated citrus oils are generally produced from distilled oils, which possess zero or very low phototoxicity, but the process of deterpenation may increase the total percentage of phototoxic constituents.



Essential oils A–Z



African bluegrass


Synonyms: Giant turpentine grass, tambookie grass, tambuti


Botanical name: Cymbopogon validus Stapf.


Family: Poaceae (Gramineae)










Agarwood


Synonyms: Agar, aloes wood, eaglewood, lignum aloe, ood


Botanical name: Aquilaria malaccensis Lamk


Botanical synonyms: Aquilaria agallocha Roxb., Agallochum malaccense (Lamk) Kuntze, Aquilariella malaccensis (Lamk) v. Tieghem


Family: Thymelaeaceae







Comments


Agarwood essential oil is one of the most expensive aromatic raw materials, being 10–15 times the cost of jasmine absolute. The oil is extracted only from fungus-infected wood. Other analyses, showing quite different constituents, have been published by Näf et al (1995) for Indian agarwood oil, and by Bhuiyan et al (2009) for agarwood oil from Bangladesh. Agarwood oil may also derive from Aquilaria sinensis (Lour.) Gilg. Aquilaria malaccensis is classed by CITES under their Appendix II: ‘species that are not necessarily now threatened with extinction but that may become so unless trade is closely controlled.’ CO2 extracts are also produced.



Ahibero


Botanical name: Cymbopogon giganteus (Hochst.) Chiov.


Family: Poaceae (Gramineae)








Ajowan


Synonyms: Ajwain, bishop’s weed, sprague


Botanical name: Trachyspermum ammi L.


Botanical synonyms: Carum copticum L., Trachyspermum copticum L.


Family: Apiaceae (Umbelliferae)









Almond (bitter, FFPA)


Botanical name: Prunus dulcis (Mill.) var. amara


Botanical synonyms: Prunus communis L. var. amara, Prunus amygdalus Batsch. var. amara, Amydalus communis L. var. amara, Amygdalus dulcis Mill. var. amara


Family: Rosaceae










Almond (bitter, unrectified)


Botanical name: Prunus dulcis (Mill.) var. amara


Botanical synonyms: Prunus communis L. var. amara, Prunus amygdalus Batsch. var. amara, Amydalus communis L. var. amara, Amygdalus dulcis Mill. var. amara


Family: Rosaceae







Systemic effects


Acute toxicity, human: There are many recorded cases of poisoning from the 19th century when unrectified bitter almond oil was widely available. A ‘druggist’, who ingested ~ 2 g of the oil, having mistaken it for another substance, survived. A colleague of his induced vomiting within 20 minutes, and observed delirium, difficulty breathing, feeble pulse, cold skin, and slight convulsions at different times during the episode (Chavasse 1939). An 8-year-old girl survived after ingesting a flavoring containing 1–2 drops of unrectified bitter almond oil. She appeared unconscious, and had no detectable pulse. Her jaw had to be forced open, and the two doctors present induced emesis, which smelled strongly of bitter almonds (Smith 1844).


A 57 year-old man ingested two drachms (3.5 g) of unrectified bitter almond oil, it was believed to be done intentionally, and was hospitalized shortly after. About 35 minutes later a stomach pump was administered, but 3 hours after the ingestion he died. On post-mortem, no abnormalities were seen in the liver, kidneys or abdominal viscera, but signs of toxicity were apparent in the heart, stomach and brain, the last two smelling of bitter almonds (Barclay 1866). In another fatal case, a 36-year-old female ingested at least two drachms of unrectified bitter almond oil, and died within 25 minutes. Post-mortem findings included an intense odor of bitter almonds in the stomach, lungs and chest cavity, black blood in the lungs, and almost no blood in the heart; the kidneys and spleen appeared normal, but the liver was slightly congested (Ellis 1863).


A feature of bitter almond oil poisoning is a lack of radial pulse and cold, clammy extremities. Survival was invariably linked to immediate medical intervention. HCN has an estimated adult human lethal dose of 50 mg, which equates to ~ 0.7 mg/kg (Reynolds 1993).


Acute toxicity, animal: Unrectified bitter almond oil acute oral LD50 in rats 960 mg/kg, acute dermal LD50 in rabbits 1,220 mg/kg (Opdyke 1979a p. 705–706).


Carcinogenic/anticarcinogenic potential: No information was found for unrectified bitter almond oil, but it contains no known carcinogens. Benzaldehyde is anticarcinogenic in humans (see Constituent profiles, Chapter 14).



Comments


The animal LD50 results cited above seem remarkably high compared with known human toxicity (also cited above), and to animal toxicity for HCN (see Constituent profiles, Chapter 14). It also seems surprising that RIFM would carry out human skin sensitization tests using 25% unrectified bitter almond oil. Presumably the oil used in the tests reported by RIFM contained very little HCN.


HCN is not present in the nuts in their natural state. Prior to distillation, the nuts are comminuted and reduced to a press-cake. This is macerated in warm water for 12–24 hours, during which time the HCN is formed by the decomposition of amygdalin, a naturally occurring glycoside. It is interesting that HCN has a similar odor to benzaldehyde, even though the two compounds are chemically unrelated. This makes it impossible to tell the rectified from the unrectified oil by smell. Rectified bitter almond oil is referred to as bitter almond oil FFPA. It was introduced by some manufacturers as a safer option in the 1850s, but the use of the unrectified oil continued until 1890, and was even available over the counter. In the mid-19th century an estimated 8,000 lb of the unrectified oil was used annually as a food flavoring in Britain (Anon 1857).



Ambrette


Synonyms: Ambrette seed, musk seed


Botanical name: Abelmoschus moschatus Medik.


Botanical synonym: Hibiscus abelmoschus L.


Family: Malvaceae










Amyris


Synonyms: West Indian sandalwood, balsam torchwood


Botanical name: Amyris balsamifera L.


Family: Rutaceae








Angelica root


Botanical name: Angelica archangelica L.


Family: Apiaceae (Umbelliferae)



Essential oil


Source: Roots


Key constituents:


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  4. Constituent profiles

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Jun 14, 2017 | Posted by in GENERAL SURGERY | Comments Off on Essential oil profiles

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