Re: Melatonin as chelator of several metals--S. African study in pubmed

[Guest guest]

Thanks, this was very interesting.

Donna

[Guest guest]

Melatonin is not a chelator in any clinically relevant sense under

physiologically realistic

conditions.

Essentially every amino acid or relative thereof (melatonin is from tryptophan)

will appear

to be a chelator when mixed in pure water with transition metals. This has no

significance

for what happens inside your body.

Andy

>

> http://www.blackwell-synergy.com/doi/pdf/10.1046/j.1471-4159.2000.0740231.x?

> cookieSet=1

>

> This document states that melatonin is a known chelator! To the degree that

> they use it to pretreat cells before proving that mercury damages cells in

> the brain (but not if pretreated with melatonin). Also, on page 2 of 6 it

> says that melatonin binds:

>

> Aluminum

> Cadmium

> Copper

> Iron

> Lead

> And

> Zinc

> (From Limson et al, 1998 Full reference and abstract from PUBMEd on limson

> paper below. )

>

> Thus it could presumbably bring zinc down too low?

> ------------------------------------

> 1: J Pineal Res. <javascript:AL_get(this, 'jour', 'J Pineal Res.');> 1998

> Jan;24(1):15-21. Links <javascript:PopUpMenu2_Set(Menu9468114);>

>

> The interaction of melatonin and its precursors with aluminium, cadmium,

> copper, iron, lead, and zinc: an adsorptive voltammetric study.

> * Limson J

> <http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed & cmd=Search & itool=pu

> bmed_AbstractPlus & term=%22Limson+J%22%5BAuthor%5D> ,

> * Nyokong T

> <http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed & cmd=Search & itool=pu

> bmed_AbstractPlus & term=%22Nyokong+T%22%5BAuthor%5D> ,

> * Daya S

> <http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed & cmd=Search & itool=pu

> bmed_AbstractPlus & term=%22Daya+S%22%5BAuthor%5D> .

> Department of Chemistry, University, Grahamstown, South Africa.

> Melatonin, a pineal secretory product, and its precursors, tryptophan and

> serotonin, were examined for their metal binding affinities for both

> essential and toxic metals: aluminium, cadmium, copper, iron, lead, and

> zinc. An electrochemical technique, adsorptive stripping voltammetry, showed

> the varying abilities of melatonin and its precursors to bind the metals in

> situ. The results show that the following metal complexes were formed:

> aluminium with melatonin, tryptophan, and serotonin; cadmium with melatonin

> and tryptophan; copper with melatonin and serotonin; iron(III) with

> melatonin and serotonin; lead with melatonin, tryptophan, and serotonin; and

> zinc with melatonin and tryptophan. Iron(II) showed the formation of an in

> situ complex with tryptophan only. These studies suggest a further role for

> melatonin in the reduction of free radical generation and metal

> detoxification, and they may explain the accumulation of aluminium in

> Alzheimer's disease.

> [NOTE FROM CAROLYN W: WHAT THEY MEAN IS THAT AS PEOPLE AGE THEY PRODUCE

FAR

> LESS MELATONIN, THUS ARE MORE VULNERABLE TO DAMAGE FROM SAY ALUMINUM. I

KNOW

> THIS BECAUSE OF THE EARLIER DOCUMENT QUOTING THIS]

> PMID: 9468114 [PubMed - indexed for MEDLINE]

> http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve & db=PubMed & list_ui

> ds=9468114 & dopt=Citation

>

>

>

[Guest guest]

Just curious Andy, how do you know? Has there been anything to

document this being true or false in the human body?

Tina

> >

> > http://www.blackwell-synergy.com/doi/pdf/10.1046/j.1471-

4159.2000.0740231.x?

> > cookieSet=1

> >

> > This document states that melatonin is a known chelator! To the

degree that

> > they use it to pretreat cells before proving that mercury

damages cells in

> > the brain (but not if pretreated with melatonin). Also, on page

2 of 6 it

> > says that melatonin binds:

> >

> > Aluminum

> > Cadmium

> > Copper

> > Iron

> > Lead

> > And

> > Zinc

> > (From Limson et al, 1998 Full reference and abstract from

PUBMEd on limson

> > paper below. )

> >

> > Thus it could presumbably bring zinc down too low?

> > ------------------------------------

> > 1: J Pineal Res. <javascript:AL_get(this, 'jour', 'J Pineal

Res.');> 1998

> > Jan;24(1):15-21. Links <javascript:PopUpMenu2_Set

(Menu9468114);>

> >

> > The interaction of melatonin and its precursors with aluminium,

cadmium,

> > copper, iron, lead, and zinc: an adsorptive voltammetric study.

> > * Limson J

> > <http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?

db=pubmed & cmd=Search & itool=pu

> > bmed_AbstractPlus & term=%22Limson+J%22%5BAuthor%5D> ,

> > * Nyokong T

> > <http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?

db=pubmed & cmd=Search & itool=pu

> > bmed_AbstractPlus & term=%22Nyokong+T%22%5BAuthor%5D> ,

> > * Daya S

> > <http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?

db=pubmed & cmd=Search & itool=pu

> > bmed_AbstractPlus & term=%22Daya+S%22%5BAuthor%5D> .

> > Department of Chemistry, University, Grahamstown, South

Africa.

> > Melatonin, a pineal secretory product, and its precursors,

tryptophan and

> > serotonin, were examined for their metal binding affinities for

both

> > essential and toxic metals: aluminium, cadmium, copper, iron,

lead, and

> > zinc. An electrochemical technique, adsorptive stripping

voltammetry, showed

> > the varying abilities of melatonin and its precursors to bind

the metals in

> > situ. The results show that the following metal complexes were

formed:

> > aluminium with melatonin, tryptophan, and serotonin; cadmium

with melatonin

> > and tryptophan; copper with melatonin and serotonin; iron(III)

with

> > melatonin and serotonin; lead with melatonin, tryptophan, and

serotonin; and

> > zinc with melatonin and tryptophan. Iron(II) showed the

formation of an in

> > situ complex with tryptophan only. These studies suggest a

further role for

> > melatonin in the reduction of free radical generation and metal

> > detoxification, and they may explain the accumulation of

aluminium in

> > Alzheimer's disease.

> > [NOTE FROM CAROLYN W: WHAT THEY MEAN IS THAT AS PEOPLE AGE THEY

PRODUCE

> FAR

> > LESS MELATONIN, THUS ARE MORE VULNERABLE TO DAMAGE FROM SAY

ALUMINUM. I

> KNOW

> > THIS BECAUSE OF THE EARLIER DOCUMENT QUOTING THIS]

> > PMID: 9468114 [PubMed - indexed for MEDLINE]

> > http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?

cmd=Retrieve & db=PubMed & list_ui

> > ds=9468114 & dopt=Citation

> >

> >

> >

[Guest guest]

>

> Just curious Andy, how do you know?

Because I actually know something about chemistry, and it is about as obvious as

1+1

equalling 2, not 3.

> > Melatonin is not a chelator in any clinically relevant sense under

> physiologically realistic

> > conditions.

> >

> > Essentially every amino acid or relative thereof (melatonin is

> from tryptophan) will appear

> > to be a chelator when mixed in pure water with transition metals.

> This has no significance

> > for what happens inside your body.

> >

> > Andy