Henna or not henna, that is the question - 1st part

INDEX
1st part: The mummy of Asru
2nd part:
3rd part:

In the first part of my article about fair-haired mummies there is a short paragrapgh about henna, which I suggest you to read before this one.
There, I pointed out that no Egyptian source mentions henna in relation to mummification or hair dyeing, and that the only alleged Egyptian source mentioning the plant today known as Lawsonia inermis is the Ebers papyrus, but probably the plant called HNW in this papyrus is not Lawsonia.
So, basically, the use of henna in ancient Egypt is scarcely documented.
I also pointed out a thing that is usually overlooked when speaking of henna. Henna, being a natural dye, can only dye tone on tone, that is, its colour adds up to the colour of your hair. This means that if you have dark hair you will never dye it red with henna. At the very most you will get copper shades, but if you want a colour like the one of natural red hair, you need to have light-coloured hair. Also, depending on the shade of red you want, you will probably need to mix henna with darker herbs.

In this article (which will be probably split into three parts) we are going to examine three studies claiming to have identified traces of henna on the hair of Egyptian mummies and we will see that, actually, they don’t provide the necessary evidence.
After that, I will briefly talk about a French article on henna, which, in my opinion, is interesting on many levels and which can help to clarify the matter.




THE MUMMY OF ASRU (circa 700 BC)
The mummy of Asru and the two associated coffins were presented to the Manchester museum in 1825. They were the first Egyptian antiquities to enter the collection.
Their exact provenance is unknown, but probably they originated at the Egyptian capital of Thebes (modern Luxor). Inscriptions on the coffin provided the information that the owner was named Asru, her mother was Ta-du-Amen and she was a temple chantress. Her duties involved singing to accompany the sacred rituals to the god Amun.
Scientific studies revealed that Asru was 50 or 60 when she died, probably around 700 BC.
As you can see, she comes from the same city as Takabuti and is dated to the same period. 

Coffin of Asru

 

In 2003 an analysis of Asru was published: Asru, an Ancient Egyptian Temple Chantress, by Rosalie Ann David and V. Garner (we have already met David in the article about Takabuti). I’m going to quote some passages:

2.3.2. The identification of henna
Evidence of the use of henna has been found on a sample of hair attached to tissue taken from Asru's scalp. The following procedure was used to investigate this sample using several distinct stages.
Optical microscopy was used to examine the hair sample, and the optical image showed a portion with obvious red colour that was lacking in the rest of the hair, where there appeared to be no pigmentation. This posed the question whether the colour was due to the addition of a colouring agent. for example henna. or to the bleaching of a naturally coloured red hair. In either case, it appeared that the two sections of contrasting pigmentation were the result of the postmortem hair growth: the colour had been absorbed into the hair during life, and new unstained hair had grown after death. When the hair was viewed using the Bio-Rad lR Microscope/Spectrometer, the red portion had additional signals assigned to aromatic and phenolic compounds that were lacking in the non-coloured portion. […]
Application of this technique to the hair sample demonstrated the presence of terpenoid compounds including cadalin and podocarpin, known constituents of vegetation extracts such as henna. […]
The ancient Egyptians are known to have used henna in several ways. The odiferous
pink or cream-coloured flowers of the shrub (Lawsonia illermis L.) [21] may have been added to the perfume of some ointments and, for both the living and the dead, the leaves may have been used to stain the palms of hands, soles of feet, and toenails and fingernails [22].
Henna was used by the Romans to dye their hair red, and the custom is still widespread amongst women in Islamic countries today. The hair of some Egyptian mummies is also evidently dyed red, but the project on Asru's hair sample is the first time that spectrometric studies have been undertaken in order to demonstrate conclusively that the dye was henna.

Basically, organic material was found on the red-coloured portion of hair, while on the white hair grown after death (post-mortem hair growth is not unusual) there was no organic material.

Now, please note the wording. The authors write: “Application of this technique to the hair sample demonstrated the presence of terpenoid compounds including cadalin and podocarpin, known constituents of vegetation extracts such as henna.”
They are not saying that these compunds are exclusive of henna. On the contrary, they are saying these compounds can be found in several vegetation extracts and henna is one of them. Besides, they don’t list all the terpenoid compounds they found: why?

But let’s have a look at the compounds they mention, cadalin and podocarpin.

Cadalin
For starters, the real name of cadalin is cadelene and is found in essential oils of many higher plants. Here’s the list of the plants that contain cadalene and, as you can verify by yourselves, Lawsonia inermis is not listed.
Cadalene has been found is some human remains from Egypt and has been linked to the Atlas cedar, a species of coniferous tree (see here and here). It has also been found on ancient Egyptian pleated textiles along with other elements, suggesting a conifer oil, probably juniper oil.
Interestinlgy, cadalene is found in the essential oil of Lawsonia inermis, but a compound identified in the essential oil cannot automatically be considered a marker of the dyeing paste. Besides, compositions of Lawsonia inermis essential oil may vary.
In any case, the presence of cadalene may be explained with a precursor present in the plant which transformed into cadalene during heating or pyrolysis and, as a matter of fact, the hair sample from Asru did undergo pyrolysis, as the authors explain in the study: 

A minute sample of the coloured hair (1-2 mg) was investigated by MSSV-GC-MS (MicroScale Sealed Vessel pyrolysis coupled to high resolution Gas Chromatography Mass Spectrometry). In this technique that was developed for the investigation of organic residues in geological materials, the sample is sealed in a silica tube and heated at 300 C [300 °C = 572 °F] for twenty-four hours; any polymeric material undergoes thermal scission to form volatile organic compounds that are released as the tube is opened and transferred in a stream of helium and cryofocussed using liquid nitrogen so that they can be analysed by conventional GC-MS.

(For more information about GC-MS see here).
So, cadalene can be a transformation product of terpene precursors during these thermal processes. To interpret this correctly, one would need to know the behavior of the various henna components under the same pyrolysis conditions.

 

Podocarpin
Apparently, a thing called podocarpin doesn’t exist.
There is the podocarpic acid and the podocarpane, both isolated from species like Podocarpus totara and Dacrycarpus dacrydioides. Podocarpus is a large genus of conifers, the most numerous and widely distributed of the family Podocarpaceae. So, no Lawsonia inermis.
I only found two plants with both cadalene and podocarpane.
One is the Taiwania cryptomerioides, a large coniferous tree in the cypress family Cupressaceae (here are its compounds), and, as you can infer from its name, the genus is named after Taiwan and the plant grows in Asia.
The other is the savin juniper (Juniperus sabina), which is native to the mountains of central and southern Europe and western and central Asia, typically growing at elevations of 1,000–3,300 metres (3,300–10,800 feet, here are its compounds).
None of them is a hair dye. 

Reconstructed head of Asru by Richard Neave (source)

 

 

And the lawsone?
Some of you may have noticed something conspicuous by its absence: the lawsone. Lawsone, also known as hennotannic acid, is a red-orange dye present in the leaves of Lawsonia inermis, as well as in the common walnut and water hyacinth. So, one would expect to find traces of it in hair dyed with henna.
However, the absence of lawsone in an ancient find is not a definitive proof that henna was not used. Over the millennia, the compound could have degraded, or it might be present in quantities below the detection threshold. For instance, in this 2024 study focused on identifying natural dyes in medieval Islamic manuscripts, the presence of lawsone was considered reliable in only four of the samples. This demonstrates that degradation can indeed make it difficult to identify henna in archaeological finds, even when sophisticated analytical techniques are employed.
In any case, the authors of the study on Asru should have explained whether they looked for lawsone and, if so, provided possible reasons why they did not find it.

 

Why citing unreliable sources?
If you read again the passage from the study I have quoted in the beginning, you will see there are two footnotes, 21 and 22: 21 refers to 1962 book Ancient Egyptian Materials and Industries, by A. Lucas, and 22 to the 1989 book An Ancient Egyptian Herbal, by Lise Manniche. 
Well, if you search both of them for the word “henna”, you will see a stream of “it is suggested… possibly… probably…”. I’m going to give some example, but you can see the rest by yourselves.

From Ancient Egyptian Materials and Industries (my bold type).

Page 87: In connexion with henna it may be mentioned that the leaves were possibly used in ancient Egypt, much as they are to-day, in the form of a paste to colour the palms of the hands, the soles of the feet, the nails and the hair. Thus, the Romans certainly employed henna, an Egyptian shrub, for colouring the hair, and probably therefore the Egyptians also, and Elliot Smith describes the hair of the mummy of Henttawi (Eighteenth Dynasty) as being dyed a brilliant reddish colour, which he suggests was done with henna.
Page 234: The materials mentioned by Herodotus and Diodorus as having been employed in the mummification process, as also certain materials stated by Pliny to have been used by the Egyptians for embalming and those found in recent times in connexion with mummies, taking them in alphabetical order, are: beeswax, bitumen, cassia, cedar oil, cedri succus, cedrium, cinnamon, gum, henna, juniper berries, natron, ointments, onions, palm wine, resins (including gum-resins and balsams), salt, sawdust, spices and wood tar or wood pitch, all of which may now be considered.

This last passage may give the idea that, in previous pages of the book, henna was mentioned in relation to the works by either Herodotus or Diodorus or Pliny, but that’s not true. None of these authors mentions henna in their works about Egyptian mummification and, as I wrote in this article I have already mentioned, no ancient source whatsoever mentions henna in relation to mummification.


From An Ancient Egyptian Herbal (my bold type).

Page 37: Red dye was extracted from the roots of Alkanna tinctoria, Rubia tinctorum (madder) and the flowers of Carthamus tinctorius. lt is possible that henna was used as well.
Page 47: Sorne Egyptians appear to have dyed their fingernails, but the nature of the red colour used is unknown. lt may have been henna.
Page 114: The leaves have been found in tombs of the Late Period and of Ptolemaic date, but the actual use of the plant as a colouring agent is somewhat disputed.
Although there is evidence that the Egyptians coloured their finger-nails, there is no proof that they used henna to do so. Sorne mummies were found to have
their hair dyed red, and henna may have been used for this.

So, you see how it works. Authors cite books to support their thesis, but when you verify these sources, you find out they don’t support said thesis. 

What is lacking in this study
The authors write: 

This finding was the starting point for an extended project at Manchester which has examined samples from other sources 123], with the aims of detecting the presence of henna in ancient Egyptian hair, using MSSV-GC-MS and comparing ancient and modern dyed samples to ascertain the differences between them.

If they compared ancient and modern dyed samples, where are the figures showing the results of the comparison? The only figure in this study refers to the palm wine used in the mummification process.
Basically, what is missing is the evidence of the following passages.
First of all, they needed to prepare authentic Lawsonia inermis leaves, a dyeing paste obtained from macerated leaves, and modern hair dyed with this paste, possibly including both untreated hair and hair treated with other plant-based dyes.
Then, they needed to subject the reference samples to the same MSSV-GC-MS treatment used for Asru’s hair, identifying which compounds are actually produced following heating to 300 °C.
Then, they needed to compare the profile of Asru’s hair with the experimental profiles, verifying the compounds through retention times, mass spectra, and, where possible, authentic standards.
Finally they needed to determine whether the observed profile effectively distinguishes henna from other plant-based dyes and from naturally red hair.

 

Egyptian mummies and modern science
In the 2008 book by Rosalie David Egyptian mummies and modern science we find the plate below with the following caption:

Visible light and infrared images of a hair from the mummy of Asru. Top left: hair (colourless) with darker coating. Bottom left: Infrared image over entire infrared spectrum, showing organic material unevenly coating the hair (red colour indicates highest infrared activity). Top right: infrared image over the range 1,600–1,700 cm -1 only, indicative of the concentration of C=O on the hair. Bottom right: Anticipated infrared absorbtion area if hair was coated with plant oils.

However, this plate is not a proof of henna, because the caption only mentions “organic material” and “plant oils”, and the red and yellow colours indicate a higher activity or infrared answer.


On page 145 of the book we read: 

Shown in Plate XVI are optical and IR images of a hair from the twentyfifth Dynasty mummy of Asru, a chantress from the Temple of Amun at Karnak. The lumpy nature of the optical picture, echoed by the average IR
picture, is considered to be due to a paste of oils and dyes applied to the scalp and hair. This theory is borne out by the uneven orange colouring on the hair, suggestive of henna.
The active ingredient in henna is hydoxynaphthoquinone, a light yellow crystalline compound when pure. In henna, it complexes and oxidises to produce the characteristic orange colour. The uneven coating on the hair suggests it was applied after death as part of the ritual preparation process rather than as a cosmetic during life, an identical interpretation to that obtained from another mummy (Plate XV). Mapping the 1,600 to 1,700- cm−1 C=O and aromatic carbon region produces an image with bright spots roughly corresponding to the orange areas in the optical picture, not inconsistent with the application of the aromatic oil/henna mix.

As usual, we have the typical wording “suggestive of henna” and “not inconsistent with henna mix”, but zero scientific evidence.
Besides, here they say “The uneven coating on the hair suggests it was applied after death as part of the ritual preparation process rather than as a cosmetic during life”, while in the 2003 study they wrote “The colour had been absorbed into the hair during life, and new unstained hair had grown after death.”

Just to make a comparison, this is a study about red colourants in archaeological textiles from pharaonic Egypt, and if you scroll it you will see several tables and figures with the results of the analyses.

Basically, the authors of the study on Asru are asking us to take their word for it, but this is science, not religion.
Just to be clear, I’m not saying henna was not found on the hair of this mummy. I’m only saying the study by David and Garner doesn’t provide the necessary evidence.

My idea is that cadalene, podocarpic acid/podocarpane and the red colour on Asru’s white hair might come from three different sources. For example, it is possible that one or more substances used during mummification were put on the mummy’s white hair (juniper resin was known for having anti-bacterial and insecticidal properties) and, over the millennia, this substance or substances coloured the white hair red.
Or, it is also possible that Asru used hair products, maybe a “gel” like the one of Takabuti, or something to avoid lice, and this product gave her hair a reddish hue after death (the Ebers Papyrus describes a remedy for lice prepared from date flour).

In the next part we will examine two more studies.