Rosewood (‘Aniba rosaeodora’ Ducke): Time to Take Heart

Rosewood (Aniba rosaeodora Ducke), also known as Cara-cara, Pau rosa, Bois de rose, Palo rosa, and Palo de rosa, is a tree found in Brazil (Amapá, Amazonas, Pará), Colombia, Ecuador, French Guiana, Guyana, Suriname, Venezuela, and Peru (Figure 1). It can reach a height of 30 m (98 feet) with a diameter of 2 m (6.6 feet), is an evergreen, and all parts of the tree are fragrant. Its highly sought-after medicinal and fragrant essential oil, is one reason this species is in decline (IUCN, 2017).

Figure 1. Rosewood; Peru, 2017

Conservation status of Aniba rosaeodora

Aniba rosaeodora is listed as an ENDANGERED species. According to the IUCN (2017), ‘endangered’ means that natural population numbers decreased  ≥50% over the last 10 years or 3 generations, assessments of wild and mature adults (those capable of reproduction) total less than 2500 and the numbers are declining (Varty, 1998), and there is a 20% probability of its extinction within 20 years or 5 generations. Click here for more information on the categories and criteria of threatened species. Not only is this species listed as endangered, but it is also protected by the Convention on International Trade in Endangered Species (CITES). The aim of CITES is to ensure that international trade (export/import) in specimens of wild species including plants, plant parts, and plant extractions (e.g. essential oil) does not threaten their survival.

Aniba rosaeodora has significantly and primarily declined because of the unsustainable harvest of its sapwood and heartwood for the essential oil. Whole trees of all sizes and thus ages, are harvested indiscriminately, and their roots are being destroyed. This type of illegal and unsustainable harvesting, as well as illegal logging and distillations, take place in remote locations to reduce costs and the chance of being detected (Figure 2). Unfortunately when these areas are discovered, they show no signs of regeneration. Further, A. rosaeodora is impacted by habitat loss, and its illegal acquisition at any cost by Koreans; it is one of the most desired woods used for Korean furniture (P. Maderas, personal communication, March 27th, 2017). Still, the real heart of this serious problem revolves around the essential oil.

Figure 2. Evidence of forest disturbance made by illegal loggers; Peru, 2017

Why rosewood (A. rosaeodora) essential oil?

Rosewood essential oil is the most commercially important oil sourced from the Amazon. It is highly valued for its fragrance and its major volatile compound – the monoterpene alcohol linalool (Figure 3). Linalool (3,7-dimethyl-1,6-octadien-3-ol) makes up 78%-93% of its chemical profile; and one study showed percentages up to 99% (Maia et al., 2007; Lupe et al., 2008; Chantraine et al., 2009). Two enantiomers of linalool, with different fragrance profiles, occur in plants: (3S)-(+)-linalool (coriandrol) and (3R)-(-)-linalool (licarcol); the latter is the prevalent form in rosewood oil, which is also the case for Chinese Ho (Cinnamomum camphora NEES) oil and coriander (Coriandrum sativum L.) oil (Letizia et al., 2003; Aprotosoaie et al., 2014).

Approximately 95% of the world’s production of linalool is used for vitamin E synthesis, and to be transformed into derivatives that enhance flavors of foods and beverages. Its fragrant properties are also essential to cosmetics and perfumes (Letizia et al., 2003; Simic et al., 2004); linalool represents roughly 70% of the terpenoids of floral scents (Stashenko et al., 2008). So it comes as no surprise that perfumers are one of the largest buyers of linalool-rich rosewood oil which is described as having floral and woody notes. Its importance in high-quality perfume dates back to the 1930s when Chanel started using it (Souza et al., 2011). The international markets, including fragrance, cosmetic, and perfume, require true and natural rosewood oil to be at least 85% linalool in order for it to be of any value (Maia and Mourao 2016). This is also the case for the healthcare industry and in academia.

Research has shown many pharmacological effects attributed to linalool. They include anti-inflammatory, anxiolytic, anticonvulsant, sedative, and hypothermic effects with the enantiomer (-)-linalool (prevalent in rosewood oil) having a greater efficacy on human stress (Elisabetsky et al., 1995; Peana et al., 2002; Sampaio et al., 2012). Soeur et al., (2011) showed that true rosewood oil, “in a defined range of concentrations”, selectively kills human epidermoid carcinoma A431 cells and pre-cancerous HaCaT cells – these are believed to be indicators of skin carcinogenesis. Aniba rosaeodora oil also showed 98% antiviral activity against avian metapneumovirus (aMPV) (Kohn, 2004), and has shown pesticidal activity against Tyrophagus putrescentiae (a cosmopolitan mite) and insecticidal activity against Trialeurodes vaporariorum (greenhouse white fly) (Maia and Mourao, 2016).

Figure 3. Molecular structure of linalool (Almeida et al., 2013)

Authenticity of rosewood oil

Certainly there is no question about the necessity and high demand for rosewood oil by a multitude of industries worldwide. Unfortunately, the high demand does not meet the supply. It was reported in 2011 that more than 2 million rosewood trees have been destroyed, and population numbers continue to decline. It is estimated that for ~40 tons of oil, about 4,000 whole trees are annually harvested without signs of regeneration (Varty, 1998; Souza et al., 2011; Ablard, K. personal observation March, 2017).

Since the 1960s, exploitation levels have declined with increased use of synthetic linalool, but not nearly enough to prevent the unsustainable and illegal harvesting of rosewood, and illegal production and trade of its oil. For example, it was announced on September 18th, 2017 that Young Living, an essential oil company, “pleaded guilty in federal court to federal misdemeanor charges regarding its illegal trafficking of rosewood oil and spikenard oil [spikenard is critically endangered on the IUCN redlist] in violation of the Lacey Act and the Endangered Species Act.”

The high demand and cost (US$80/kg [FOB, Manaus] (Souza et al., 2011) of unadulterated and quality-controlled true rosewood oil that is backed with a CITES permit, limits and complicates the market for retailers and consumers. High-end retailers and makers of perfumes, essential oils, and cosmetics who attempt to get true rosewood oil, may unknowingly receive adulterated oil.  Adulterated rosewood oil is usually a blend of rosewood oil from rosewood species other than A. rosaeodora, which naturally contain less linalool, and synthetic oil (~1/10th the cost of true rosewood oil), Chinese Ho and/or leaf oils. Said adulterated blends are reported to have replaced true rosewood oil in low- to mid-range perfumes and cosmetics, and those used in household products (Souza et al., 2011), and in aromatherapy.

Dr. James Simon, Distinguished Professor of Plant Biology, along with his group at Rutgers University, and I are collaborating on a research project to explore this. If you have rosewood essential oil, and would like to participate, please contact me for details at kelly.ablard@gmail.com

Consumer power

If possible, do not purchase essential oils or any extracts from threatened plants, or products that contain them. Essential oils and extracts that should be on your radar include Palo santo (Bursera graveolens), Spikenard (Nardostachys jatamansi a.k.a N. grandiflora), Sandalwood (Santalum album), Guggul [a.k.a. common myrrh] (Commiphora wightii), Silver white fir (needle) (Abies alba), Agarwood (Aquilaria rostrata), Juniper berry (Juniperus communis), Atlas cedarwood (Cedrus atlantica), Bay laurel (Laurus nobilis), Araucaria (Nelocallitropsis pancheri), Rosewood [English] (Dalbergia abrahamii), Olive (Olea europaea), Sweet almond (Prunus amygdalus), Spanish cedar (Cedrela odorata), Elemi (Canarium luzonicum), Sassafras (Ocotea pretiosa), Siam wood (Fokienia hodginsii), and of course Rosewood (A. rosaeodora).

If you must purchase them, make sure the essential oil-bearing plants are sustainably managed, the essential oils or extracts are ethically sourced, and are backed with a CITES trade permit when necessary. CITES permits are required for Red sandalwood (Pterocarpus santalinus), Guaiac wood (Bulnesia sarmientoi), Agarwood (Gyrinops spp. and Aquilaria spp.), African sandalwood (Osyris lanceolata), Himalayan spikenard (Nardostachys grandiflora a.k.a. N. jatamansi), Indian rosewood (Dalbergia darienensis), American ginseng (Panax quinquefolius), Chinese ginseng (P. ginseng), and Rosewood (A. rosaeodora).

Retailers who are not transparent about their practice of acquiring these special oils, or who are not willing to help protect these species from extinction within their business framework, should be avoided.  I had the great fortune to visit Enfleurage, New York’s first and only store specializing in essential oils from all over the world, and to speak with their Production Manager, Joe Richkus (Figure 4). The wonderful thing about Enfleurage, is that according to Joe, they are working to learn “firsthand the whole story from seed to bottle” for 100% of their oils. They are  “making great headway in finding new sources on our explorations of new farms in different locations and we continue to make this increasingly true for more and more of our oils,” which they want  to be “100% organic and/or sustainably wildcrafted.” Joe is unique in that he is aware of the conservation issues surrounding rosewood (A. rosaeodora) essential oil, and is taking the necessary steps as a retailer to help protect this species, and to provide for their customers unadulterated, legally-backed, and ethically-sourced oil. For example, he has been diligent in his attempts to research, and obtain documentation on, sustainable management of the rosewood and CITES approval for its legal trade of ethically-sourced oil. And without ongoing “absolute proof” of this process, Enfleurage will explore “not selling it” (please see update below). It is this level of transparency, quality-control, and willingness to stop selling oils from threatened species, that should be taken into consideration when vetting essential oils retailers – their transparency and their respect for plants sets Enfleurage apart.

Update 10/28/2017: Our collaborative efforts have paid off! Enfleurage will no longer be selling rosewood (A. rosaeodora) oil, or using it in any of their blends. Their source was unable to provide authentic documents ensuring ethical sourcing and legal trade of the oil.  Thank you, Enfleurage for demonstrating your commitment to ethically-sourced essential oils and helping to protect endangered essential oil-bearing plants.

 

Figure 4. Enfleurage Production Manager, Joe Richkus (l) and Store Manager, Tom Carson (r)

When it comes to rosewood A. rosaeodora, it is time to take heart. We must educate ourselves, spread the word, be smart about our purchases, respect and remember the indigenous people who have a spiritual connection to this tree and who rely on its medicine, and we must work together to create a healthy and sustainable population of trees for many generations to come. To get involved and/or to find out more about being a part of the research on rosewood oil that Dr. James Simon, his group, and I are collaborating on, please contact me.

References

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