Benoit Roger, Ph. D. & Alexis St-Gelais, M. Sc., Chemist
Vetiver (Vetiveria zizanioides, syn. Chrysopogon zizanioides) is one of the essential oils we receive the most often for analysis. This is also one of the most complex oil to analyse as it contains almost only sesquiterpenoids among which a lot of unknown compounds with poor separation on gas chromatography. However, the composition of the samples we receive is quite consistent for a given origin (see in table 1).
Recently, we received a vetiver sample featuring an atypical composition. This was a composition we had never seen (see last column ‘’NG’’, on table 1). The conclusion for this kind of case is never easy to draw but we had to tell our customer that there could be something wrong with this sample and that it may have been polluted or mixed with another oil (even if we couldn’t identify which one it could be). Our customer told us it should not be the case as the oil directly came from a tribe in West Papua which only worked on vetiver and he introduced us to the tribe. They kindly accepted to send us the vetiver roots so that we could distill them and check the composition. We did it and we found the same composition as the first sample we received. This unambiguously confirmed the oil purity, as we could verify the plant material ourselves before use. Furthermore, its smell was gorgeous.
Table 1: Average concentration (%) of the main compounds we observe in the Vetiver essential oil we analysed so far (approx. 100 samples) depending on their origin.
The data shown in table 1 are consistent with the literature (at least for the main compounds and considering the complexity of this essential oil). P. Champagnat et al.1 also report the composition for some samples from other origins: Brazil, Salvador, Mexico, China, Madagascar, Reunion, but they did not report any samples containing valerianol and agarofurans. However, this is not the first report of these compounds2,3 in Vetiver essential oil but to the best of our knowledge they were never reported at such high concentration. They rather seem to be inconsistently present and/or at too low concentration to be routinely detected with classical GC analyses.
In any cases, this vetiver coming from the Meyah tribe in West Papua is clearly apart from what we find in the market and in a world constantly looking for new or unique products, this ‘’atypicality’’ may help this tribe to grow this activity and live from it. At least that’s what we wish for them.
This also reminds us that there is still a lot to learn about aromatic plants and that some essential oil that look unusual, suspicious or even polluted may also be very nice essential oil from a new (chemo)type or from an unusual origin. This story is even an excellent example of how producers, retailers and labs can work together to sort out odd situations. When something unusual is found in an oil, a lab should tell its customers. Often in such cases, the retailer of the oil, or the producer directly, will dispute the lab conclusion stating that they produce an exceptional product that simply stands out from the crowd. This could be true, but it does not provide any ground for the laboratory to review its conclusion. The only way to truly demonstrate this is to help the labs see for themselves, in a transparent way. This is exactly what all people involved in the case of this vetiver did and we thank them for this.
PhytoChemia does not receive any compensation for this work and all work were made out of scientific curiosity and to advance knowledge in our field of activity.
References:
1P. Champagnat, G. Figueredo, J.-C. Chalchat, J.-M. Bessiere. A Study on the Composition of Commercial Vetiveria zizanioides Oils from Different Geographical Origins. J. Essent. Oil Res., 2006, 18, 647.
2N. Hanayama, F. Kido, R. Sakuma, H. Uda, A. Yoshikoshi. Tetrahedron Lett., 1968, 58, 6099.
3P. Pripdeevech, S. Wongpornchai, P. Marriott. Comprehensive Two-Dimensional Gas Chromatography–Mass Spectrometry Analysis of Volatile Constituents in Thai Vetiver Root Oils Obtained by Using Different Extraction Methods. Phytochem. Anal., 2010, 21, 163.
Photo Credits: Michael Cochran
Photo Credits: Hubert Marceau & Benoit Roger
