Re: Supplements for Neuropathy; counteracting niacin flush PGD2Kofi wrote:
> In article <nospam-9BE4F2.06453308062008@newsclstr03.news.prodigy . net >,
> Bob Arnold <nospam@aol . com > wrote:
>
>
>>In article <kofi-837123.12350806062008@news.east.earthlink . net >,
>> Kofi <kofi@anon.un> wrote:
>>
>>
>>>I keep trying to tell people *not* to inhibit the COX enzymes unless
>>>they've got a life-threatening condition like cancer.
>>
>>Really? So you tell people not to take curcumin or turmeric, green
>>tea, resveratrol, fish oil, Rosemary, or low-dose aspirin?
>
>
> Yeah. They *can* cause unexpected long-term problems in people with odd
> forms of autoimmunity because of their actions on PGE2. It depends on
> what else they're doing to balance it out. These substances are all
> quite complicated and they may inhibit one type of enzyme in one cell
> and do something completely different in another.
>
> Most people taking curcumin or green tea aren't really getting
> pharmacological levels of the substances for sustained periods of time.
> EGCG requires citric acid or lemon juice to protect it through the
> stomach and curcumin requires CYP inhibition. I've actually tried the
> later and it severely exacerbated my autoimmune problems and difficulty
> fighting infections. TGF-B1 inhibition/PPARgamma agonism might have
> played a significant role. In particular, PPARgamma increases
> transglutaminases which Celiacs target with autoantibodies. TGF-B1
> activates Tregs.
EGCG has different effects on the pancreas than it has on the liver.
EGCG can reduce some natural endogenous antioxidant enzymes at high
enough doses. "The effect of NAC and SOD on PEPCK and G6Pase gene
expression was also examined. As expected, NAC and SOD completely
reversed EGCG-mediated PEPCK and G6Pase gene repression. NAC partially
inhibited the effect on insulin-mediated repression of the PEPCK gene,
but not the G6Pase gene (Fig. 6, panels B and C). These results show
that EGCG regulates tyrosine phosphorylation and gene expression by a
redox-dependent mechanism and provides additional evidence that the
PEPCK and G6Pase genes are regulated by multiple signaling pathways.
[...] The effects of EGCG are reversed by NAC and SOD, whereas those of
insulin are mostly unaffected, suggesting that the former acts by a
different mechanism. In most cell types, EGCG is an antioxidant.
However, in hepatoma cells, EGCG is a pro-oxidant. This is not
completely unexpected because other compounds, such as ascorbate, can
act either as an antioxidant or pro-oxidant, depending on the cellular
environment (47). Curcumin, a phytochemical responsible for the color of
turmeric, has antioxidant activity in many different cell types but
displays pro-oxidant qualities in the presence of transition metals,
such as copper, which exist in the kidney and liver at relatively high
concentrations (48).
The data presented here suggest that EGCG regulates protein-tyrosine
phosphorylation by modulating the redox state of the cell. One possible
mechanism for the observed actions of EGCG in hepatoma cells is the
inhibition of PTPs, which contain an oxidizable cysteine in their active
site (39, 49). It is possible that EGCG causes oxidation of this
cysteine residue in redox-sensitive phosphatases, and NAC and SOD
reverse this effect. Several PTPs, including PTP-1B and leukocyte
antigen-related phosphatase, dephosphorylate the insulin receptor and
IRS-1, making these phosphatases candidates for modification by ROS
produced in response to EGCG (50-52)." Source: Epigallocatechin
Gallate, a Constituent of Green Tea, Represses Hepatic Glucose
Production - * w w w .jbc.org/cgi/content/full/277/38/34933
Frank