Neroli

Neroli

Neroli is an essential oil made from the petals of the bitter orange.  The amount of oil in a petal isn’t very high so it takes a lot of  them to make much oil.  So it isn’t surprising to learn that the use of neroli oil was originated by an aristocrat.  The production and use of neroli goes back to the Duchess of Nerola in seventeenth century Italy, whose exquisite taste and deep pockets led to her name being given to the oil.  Even today its stupendous price tag limits its use to very low levels or very expensive products.

Not everything that is expensive is necessarily worth the money.  Caviar always strikes me as much like fish paste only too salty and blind tastings reveal that exclusive wine vintages are much like the mid price alternatives.  But neroli oil really is something special.  It has a freshness and brightness that is rare amongst any fragrance material, especially essential oils.

Nobody has ever got very far explaining how different chemicals smell.  The relationship between components of natural products and how they affect the nose is something that is of great interest to perfumers and chemists alike.  I am not really much of an expert on this kind of thing.  There are plenty of people who know a lot more about this kind of thing than I do.  But this is my blog,  so here are my opinions.

Chemistry of Neroli

Looking at the chemical constituents of neroli it is distinctly different to other citrus oils. Most of this family is characterised by a high level of limonene.  Limonene is a very distinctive smell that immediately reminds you of oranges.  Neroli on the other hand is pretty low in limonene – there is enough in there to keep the family resemblance in mind – but it isn’t the main action.  The biggest component, nearly half of it, is linalool.   This is much more common in the lavender family.  Maybe that is one of the reasons that neroli smells so distinctive.

But there is more to the neroli story.  There are also some things in there that are probably having a more subtle effect.  For example there is nerolidol, which as the name suggests was first found in this oil.  It was later found to be a common constituent of flower oils.  More recently it is being investigated as a skin penetration enhancer.  Could this also work on the nose, making it easier to smell the other subtle components?

As an aside, I really like the structure.

Nerolidol

Nerolidol

In some way it is a shame this stuff is so expensive.  But it does make the experience of smelling it rarer and so perhaps, a little more special.

Notes on Neroli for Chemists

Neroli’s CAS number is 8016-38-4.   72968-50-4 pops up from time to time, but is strictly speaking bitter orange peel oil.  Right species, wrong organ.

The soulless bureaucrats at the EU have given it the official name Citrus Aurantium Flower Oil.  This is of course literally true, but it is a shame to miss out on the name neroli.  Strictly speaking, this is how it should appear on ingredient lists.  The use of descriptors in brackets is now so widespread that I think you could argue that calling it Citrus Aurantium (Neroli) Flower Oil has become custom and practice.

As with any oil containing a lot of linalool, watch out for oxidation.

 Reference

J Pharm Pharm Sci. 2013;16(4):551-63. Effect of terpenes on the skin permeation of lomerizine dihydrochloride. Furuishi T1, Kato Y, Fukami T, Suzuki T, Endo T, Nagase H, Ueda H, Tomono K.

Thanks to Wikipedia for the structure of Nerolidol

 

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