It is estimated that around 3000 essential oils are produced from diverse aromatic plants in different countries and more than 400 essential oils are traded in the global markets. Each essential oil has a characteristic aroma that can be distinguished from other essential oils. The characteristic aroma of an essential oil is attributed to the presence of a number of compounds (both major and minor) and their proportion or percentage in the essential oil. Essential oil from the same aromatic plant growing in different countries or under different agro-climatic conditions in the same country contains slightly different chemical composition. Working with various aromatic crops, I have recorded more than 350 compounds in curry leaf essential oil produced in more than 10 countries. Did any one record more number of compounds in any other essential oil?

Yes, Essential oil is a mixture of different compounds. 

Dear Prof. Vinesh

How many compounds are there in that mixture? What is your experience?

Best wishes.

Despite mammoth scientific and technological advancement, modern science can still not unlock the secrets of essential oils Chemical components that nature combines to make up the oils, could not be replicated till date. Even after identifying hundreds of constituent chemicals, mixing those constituents in right proportion and with the best human efforts, one would still not have an identical oil. Such a copy of an oil will not found to have the same impact as the natural and pure essential oil. It may be due to the reason that an essential oil has more than several hundred components, and figure may run upto thousands; many of them may not be detected or indentified so far. As such, it is not possible to say about the definitive number of compounds an essential oil can contain.

Dear Dr. Tripathi

Thank you for your interesting answer.

Natural essential oils have soft and rounded odors while reconstituted and synthetic oils have harsh odors.

Best wishes.

Dear Dr Rao

Essential oils are the secondary metabolite deposites, that we have published several papers inthis line.

Till date it is not characterised a single oil about the Constituent no.

Not ebven posiible, as we know secondary metabolite secretions are derectly regulated with plant physiology. At the same time the physiology of aplant is again proportionately related to both biotic and abiotic conditions of the ecosystem and/or the habitat. To the stresses too.

That is why even if we characterise one oil to the extent maximum we can infer these are the constituents present in the oil from this ecoregion. Which can not be taken as standard for all the ecoregions of the world.

Dear Dr. Rath

It is nice to correspond with you after a long time. Yes, I agree with your observations. My query pertains to literature search on any essential oil and how many compounds have been identified so far from different parts of the world where this essential oil has been produced or investigated. I gave some examples based on my literature search while working with these essential oils. I would like to know about the information you have on any essential oil for the benefit of RG members particularly students and research scholars.

Best wishes.

Dear Rao,

it really is difficult to determine how many of the compounds included in the essential oil of a single species. We are still limited methods of identification, which, as far give us the opportunity to determine approximately 300 compounds in one essential oil and it is only when we give a mixture of several evaluation methods, GC, GC / MS, GC / MS FID. To this are the primary type powiecmy method using a densitometer TLC, but they generally show the content of these występujęcych in large amounts. It is tempting to connect HPLC UP and the like. But this is not the essence. It seems to me that we have to carry out the identification and assessment of its membership at the level of varieties, harvest date, plant organ, the climatic conditions. Because really examining each of us gets the same species often extremely different results, which are similar in content devoured some of the active compounds. And I think today is the main task of all who study the composition of the substance making up the composition of the essential oils.

Dear Dr. Agnieszka

Yes I agree with you that with the existing facilities it is not possible to isolate and identify all the compounds an essential oil may contain and the composition is influenced by several factors modifying the number of compounds and their percentages in the essential oil. What I essentially want from RG members who have researched on the chemical compositions of essential oils is that, how many compounds have been identified so far in any species or variety from different parts of the world. For example, In India if scientists from different locations identified 100 compounds in palmarosa (Cymbopogon martinii var. motia) and scientists in other countries identified 100 more compounds in addition to the 100 already identified; the total number of compounds identified in palmarosa from different parts of the world adds to 200. My experience so far has shown that in curry leaf more than 350 compounds have been identified from 10 different countries. Similarly I gave other examples. If you can give similar examples from different species it will greatly help young researchers working on these species. It will also provide an opportunity to check whether any new compound(s) are present in the same species in other parts of the world. It will also help in identifying new chemotypes.

I hope my question is clear now.

Best wishes and thank you for your informative contribution.

The number of compounds in the essential oil, and in general in the plant extracts, is extremely variable. In theory, each extract would require a chemical analysis. It is not practicable. Therefore, for a regulatory and/or commercial purpose, it should be better focusing on the main compounds and on the compounds of concern. Of course, we can rise questions about what is consider “main” and “concern”.

Dear Roberto

Thanks for your contribution. The idea is to review the literature about the number of compounds identified so far in an essential oil by researchers from different countries so that it becomes easy for any other researcher to report the discovery of a new compound in the same essential oil. In essential oils both major and minor components contribute to the aroma and therefore are considered important. sometimes the price of a trace or minor aroma chemical isolated or separated from the essential oil is much higher than that of isolated major aroma chemical or compound. I am looking for number of identified compounds in different species.

The essential oil of Lemon grass / citratus not I examined, but it seems to me that is a very good idea, which can be used also for other plant species. Some raw materials are fairly well researched depending on the location and method of obtaining cultivation. Only, as always, it is difficult to get to certain information, the restrictions publishing, the language issue like. It would be interesting to create such a list of information to a wider range of raw materials.

I reviewed the literature on lemongrass, rose-scented geranium, curry leaf, Tagetes minuta (Indian literature only), cornmint etc. and published the results either in research papers or book chapters. This has helped in identifying new compounds in different crops, new chemotypes, gaps in research on specific essential oils and their methods etc. which led to further research on these species. I am collecting literature on Artemisia annua, but the problem as you rightly pointed out is the non-availability of local journals on the internet and language as most of the papers were published in Chinese. So far the total number of compounds I could collect in this species is close to 600. Another problem is the authentication of some of these compounds as they were reported only once and were not reported by other researchers. 

Keeping the problems aside, this technique is helpful in several ways. I wish young RG members with access to the net will be benefited.

It is a very good idea to create the list of  chemical compounds. Moreover, metadata, such as chemotypes or other information, could help.

Thanks for endorsing my view point.