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Jots and Thoughts

The musings and notes of the Threla team about body and skincare products.

Essential Oils, Hydrosols, Absolutes and Resins: The Derivation of Natural Scents

Threla LLC - Monday, June 11, 2012

One of the reasons for our love affair with personal care and home fragrance products is our abiding attraction toward scents.  Whenever possible, we use naturally extracted scents for their authenticity, allure, and complexity.  For scents that don’t lend themselves to natural extraction due to the fragility of the fragrance components and/or the prohibitive costs, we use phthalate-free fragrance oils.  Our lotions, lip balms, facial products, and deodorants (i.e. any product that stays on the skin) are naturally scented, and we refer to the scent components in their ingredients list variously as essential oils, absolutes, resins, distillates, etc.

In this jot we aim to explain what these terms mean and how natural scents are derived.   The terms are typically associated with the method of extraction of the scent components.

Essential oils are scent extracts derived from plants by distillation or by mechanical pressing.  Distillation entails heating the plant material to vaporize the volatile fragrant components then cooling the vapor to collect them as a liquid or a solid distillate.  For example, lavender essential oil is obtained by steam distillation in which steam is injected into a vessel containing lavender buds.  The steam heats up and breaks down the plant material, and carries with it the volatile fragrant oils in the plant.  The mixture of steam and oils is then condensed back into a liquid and separated.  The oil thus obtained is lavender essential oil.  The water phase contains water-soluble fragrant components of lavender and is dubbed lavender distillate or hydrosol, or more colloquially as “lavender water”.  We use this hydrosol in our facial mists.

Oils obtained by mechanical pressing (also known as cold pressing or expression) include citrus essential oils. The peel of the citrus fruit or sometimes the entire fruit is pressed to rupture the oil-containing cells and release the essential oils.  If entire fruits are used, the mixture is then centrifuged to separate the oil from the aqueous phase.  Orange, grapefruit, lemon, tangerine, mandarin, and other citrus essential oils are obtained by this method.

The fragrant components of certain plants are too delicate for steam distillation and too scarce for mechanical pressing.  Solvents such as volatile hydrocarbons (e.g. alcohol and hexane), solid oil or fat, or supercritical carbon dioxide (which is a liquid) are then used to extract the oils in a gentle fashion.  For example, to obtain jasmine absolute, fresh jasmine blossoms collected early in the morning are laid onto thin substrates coated with a solid oil/fat. Over 1-2 days, the fragrant components from the flowers are transferred to the oils.  The old blossoms are then replaced with fresh-picked ones until the solid oil is saturated.  This solid product is known as the concrete (or pomade) and contains non-fragrant wax and other plant material in addition to the fragrant components.  A volatile solvent such as alcohol or hexane is then used to extract the fragrant oils from the concrete.  After the volatile solvent is evaporated off, the resulting product is known as the absolute.  Absolutes tend to be richer and more concentrated and complex than essential oils derived by distillation or cold processing; their cost is commensurately higher.

Resins, such as benzoin and frankincense resins, are extruded from trees by slashing the bark and collecting the sap.  These resins are often very thick and difficult to work with and are sometimes converted to essential oils by steam distillation or to a more fluid resin by solvent extraction.

Through the above extraction methods, we are able to experience a portion of the bounty of scents from nature even when we are not within smelling distance of the actual plant.  In this way we have discovered the scents of plants in lands we have not yet seen.  If you have a favorite essential oil, absolute or resin, we would love to hear more about it.  We always relish a new olfactory treat.


The Hidden Dangers of Phthalates

Threla LLC - Sunday, February 28, 2010

We are usually not given over to dramatics particularly in the choice of a jot title but “hidden dangers” aptly describes the current situation with phthalates.

What are phthalates?  
Phthalates (pronounced “thal-ates”) are esters of phthalic acid (or benzene-1,2-dicarboxylic acid, to the chemically inclined). They include di-ethyl phthalate (DEP), di-isobutyl phthalate (DIBP), di-n-butyl phthalate (DBP), and di-n-octyl phthalate (DOP), to name a few.

Commonly used as plasticizers to make plastics more flexible and easier to process, phthalates occur in a wide range of products such as vinyl shower curtains, upholstery, plastic toys, paints, adhesives, and yes, cosmetics too. (BTW, that new car smell that some of us find so pleasant - that’s probably phthalates at work.) In the realm of cosmetics and personal care, phthalates are used in nail polish to render it chip resistant, and in hairsprays to create pliable coatings so your beautifully styled hair won’t feel crunchy. The presence of phthalates in these products should be indicated on the ingredients list on the label. They could be hidden, however, if they are used in fragrances as solvents or fixatives. Manufacturers are not required to disclose the ingredients of fragrances because of their proprietary nature; hence, the consumer would only see “fragrance” on the ingredients list. (To be fair to the cosmetics industry, phthalates are also “hidden” in a host of other products that do not require an ingredients label, such as shower curtains, intravenous bags, and plastic bottles.)

So what’s the danger? 
Because of their ubiquitous nature, we are constantly exposed to and consequently harboring phthalates in our bodies. A study by the U.S. Centers for Disease Control (CDC) in 2000 found metabolites associated with phthalate exposure in every single of the 289 people tested, with the highest levels recorded in women of reproductive age [1].

This finding is particularly worrisome, as phthalates have been shown to be reproductive and developmental toxins [2]-[5] and may contribute to what is known as “testicular dysgenesis syndrome”: increasing incidence of birth defects of the male reproductive tract such as undescended testis, and lower sperm count [6]. (Phthalates are believed to inhibit testosterone synthesis during the critical period of fetal development when masculine traits are beginning to form.) While a lot of attention has been focused on the "demasculation" of boys by phthalates, women are not immune to their effects. Phthalates are implicated in premature puberty in girls [7], and in animal studies, they appear to suppress estradiol production, prolong estrous cycles, and cause anovulation (no egg released in the cycle), a common cause of infertility [8]. Furthermore recent studies suggest that prenatal phthalate exposure may be linked to lower birth weight in newborns [9] and disruptive behavior in offspring [10].

What’s being done? 
The use of a number of phthalates in cosmetics has been banned in the EU, Japan, Taiwan, and other countries. No such restrictions exist yet in the U.S. where the FDA has not taken regulatory action, citing insufficient evidence of causality. The Cosmetic Ingredient Review (CIR; a trade  panel that reviews cosmetics ingredient safety) has asserted that phthalates are safe as used in cosmetics, the argument being that they are used in much smaller quantities than doses shown to cause adverse effects (yes, but there are risks of bioaccumulation from repeated exposure). Phthalate chemical producers cite the decades long history of use as evidence for their safety and say any alternative would be less tested and less safe. Their stance is not surprising; however to maintain the status quo in light of mounting evidence that phthalates are not benign would be a huge disservice to us and our children . 

Changes are coming, albeit slowly. Congress has banned the use of three types of phthalates (DBP, DEHP, and BBP) in children’s toys effective March 2010. Pressure from environmental and consumer advocacy groups has caused several cosmetics companies (OPI, Orly, Sally Hansen) to reformulate their nail polishes without phthalates. The EPA announced in its Chemical Action Plan in December 2009 that it will evaluate the risks of 8 phthalates “because of their toxicity and the evidence of pervasive human and environmental exposure to these chemicals.” [11] EPA intends to add them in autumn 2010 to the Concern List under the 1976 Toxic Substances Control Act “as chemicals that present or may present an unreasonable risk of injury to health or the environment.”

What we are doing 
We talked about parabens in an earlier jot, and if we were to compare these two suspected endocrine disruptors, we would put phthalates as higher risk (rest assured they are both excluded from our products). We are mindful that they may be hidden in fragrances; hence we use only phthalate-free fragrances in our bath and home scent lines. Products that are expected to linger on the skin, e.g. lotions, lip balms, and deodorants, are scented with natural essential oils, absolutes, and oleoresins. These are all natural fragrances that we invest a considerable amount of effort and expense into procuring and using. We are also in the process of reducing (and eventually eliminating) the use of shrink wrap in our products. You may find changes in the packaging of some of our products in the weeks ahead as we remove shrink wrapping and add tamper-evident paper seals. While the shrink wrap does not contact the products directly (and should not transfer to you), we feel we should not potentially add to the phthalate load in the environment. 

At home, we have switched to fabric shower curtain liners and are happy to realize that they can be laundered and reused. We also avoid storing and heating food in plastic containers, and our cars, because of their age, no longer have the new car smell.

References: 
1. Blount et al. Levels of Seven Urinary Phthalate Metabolites in a Human Reference Population. Environmental Health Perspectives. 108 979-982 (2000) 
2. Park et al. The plasticizer diethylhexyl phthalate induces malformations by decreasing fetal testosterone synthesis during sexual differentiation in the male rat. Toxicological Sciences. 58 339-349 (2000) 
3. Barlow et al. Male reproductive tract lesions at 6, 12, and 18 months of age following in utero exposure to di(n-butyl) phthalate. Toxicologic Pathology. 32 79-90 (2004) 
4. Gray et al. Perinatal exposure to the phthalates DEHP, BBP, and DINP, but not DEP, DMP, or DOTP, alters sexual differentiation of the male rat. Toxicological Sciences. 58 350-365 (2000)
5. Swan et al. Decrease in anogenital distance among male infants with prenatal phthalate exposure. Environmental Health Perspectives. 113 1056-1061 (2005) 
6. Skakkebæk et al. Testicular dysgenesis syndrome: an increasingly common developmental disorder with environmental aspects. Human Reproduction. 16 (972-978) 2001 
7. Chou et al. Phthalate exposure in girls during early puberty. Journal of Pediatric Endocrinology & Metabolism. 22 69-77 (2009) 
8. Lovekamp-Swan et al. Mechanisms of phthalate ester toxicity in the female reproductive system. Environmental Health Perspectives. 111 139-145 (2003) 
9. Zhang et al. Phthalate levels and low birth weight: A nested case-control study of Chinese newborns. The Journal of Pediatrics. 155 500-504 (2009) 
10. Engel et al. Prenatal phthalate exposure is associated with childhood behavior and executive functioning. Environmental Health Perspectives. In Press (2010)
11.  http://www.epa.gov/oppt/existingchemicals/pubs/actionplans/phthalates.html

Posted by THY and PP

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