Lots of heavy henna info...scientific

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Posted by Kenzi on November 10, 1999 at 04:28:14:

I just ran across a site in my endless searching for henna stuff and
they gave a lot of good and scientific info about henna, stuff I
never knew before.

Here is what they say about henna allergies:

"Henna is extremely safe, having been used for centuries In Asia and
Africa.

In places where the plants grow wild and the local population uses
henna from a young age, allergies to henna are nearly unheard of.
However, in the west, especially amongst those individuals who have
never used henna and have sensitive skin, there may be (though very
rare) allergic reactions to the henna.

Before using any cosmetic product extensively, including any oil,
powder, plastic, or adhesive - test a small amount first to make
sure you are not allergic.

Red blood cells, or erythrocytes, are particularly vulnerable to
oxidants. Any deficiency in the hexose-monophosphate shunt or in
glutathione metabolism as a result of impaired enzyme function can
lead to destruction of red cells.

The most common of these deficiencies is in the enzyme Glucose 6
Phosphate Dehydrogenase. This is a genetic deficiency which is X-
linked and found in approximately 10% of African Americans and to a
lesser degree amongst Americans of Mediterranean descent. This
deficiency is actually beneficial to some degree in that it helps
protect against Plasmodium falciparum - the deadliest type of
malaria. However, as a result of a decrease in this enzyme, exposure
to certain agents including anti - malarial medications may result in
the oxidation of GSH to Glutathione through the generation of H2O2.

Because GSH is not regenerated as effectively in G6PD deficient
individuals, the peroxide builds up and oxidizes both heme and
globin. These oxidized constituents, called "Heinz" bodies, attach
to the Red blood cell membrane and make them susceptible to hemolysis
in the spleen by macrophages.

Ingestion of some types of henna, especially if it has not been
tested, and may contain dead insects, soil, roots and stems along
with hennotannin precursors, may cause red blood cells hemolysis.

Also, Do not try cooking with henna or leaving it anyplace where a
child might accidentally eat it. Do not make drinks with henna, use
it as a suppository, or near your ears, nose, eyes, mouth or
genitalia.

What is sold as powdered henna often has significant impurities such
as INSECTS, DIRT, STEMS, and PESTICIDES! "

And then on the subject of releasing hennatannins:

"In order to answer this - we need to tell you a little bit about the
chemistry of henna and specifically - hennotannins. (If you don't
like chemistry, please skip that section)

Hennotannins, like other tannins, are mixtures of complex dihydric
producing condensed and trihydric producing pyrogallol phenols. They
have very large molecular weights and are non-crystallizable
colloids, which uniformly are soluble in acetone and alcohol.They are
partially soluble in water, and easily form precipitates with
metallic salts, proteins and alkaloids. They are eluted ideally in
competition with hydrogen ion excess in non - metallic solutions with
pH range of 4 - 6.

The use of lime, distilled water coffee and tea all help adapt "hard"
or calcium-phosphate rich water with its higher pH buffering capacity
for use in hennotannn elution. Ideally, one should use soft
rainwater, in fact - try collecting some rainwater for applying
henna - it makes a big difference! If the pH is really low- for
example as low as 4.2 in the Rio Negro in Brazil- hennotannins from
plants will leech out so much that the water in the river itself is
dark reddish-brown!

The chemical characteristics necessary for ideal hennotannin
separation from its dried cell wall location are different than those
that are ideal for henno-tannin absorption into the granu


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