Comment · Fri, March 20, 2020 · Natrium Health & Nootropics Depot
You might not want to be taking EGCG now that coronavirus is afoot
Original post in this thread
redditinface · 14 points
Emphasis on might. But Dr. Fauci lays out his concern about ACE inhibitors and coronavirus in his coronavirus update today, and EGCG is an ACE inhibitor.
But I want to emphasize that the jury is still out on this, and that several cardiology associations do not think the current evidence supports any action at this time.
What they were answering
WallachianVoivode · 3 points
That study was saying that vitamin C inhibited EGCG's ACE inhibiting effects, not EGCG's entire redox cycle. \[...\] Vitamin C could be counteracting the ACE effects by some other mechanism, while not affecting the zinc ionophore effects.
It says in the abstract that "co-incubation of EGCg with borate or ascorbic acid significantly diminished the EGCg inhibition \[of ACE\]". Only thing I see in common between vitamin C and borate is their reductive capacity. The abstract concludes: "These results suggested that EGCg might allosterically inhibit the ACE activity through oxidative conversion into an electrophilic quinone". Increasing the concentration of vitamin C shifts the equilibrium towards the reduced form of EGCG, preventing it from interacting with ACE.
Vitamin C could be counteracting the ACE effects by some other mechanism
We have no literature to back this up, also very unlikely.
\[you explain how SARS-CoV-2 binds to cells\]
So what about zinc and ACE2? Zinc is binding to ACE2. It does not appear that binding is inhibited by ACE inhibitors, which is good.
That's quite a... leap. First part is irrelevant. Zinc binds to ACE2, okay. Why do you mention ACE inhibitors and why would ACE inhibitors block zinc from binding ACE2? ACE inhibitors are specific for ACE1, and don't bind to the zinc site. Why is it good? I'm confused.
It's chelating with…
u/MisterYouAreSoDumb · Natrium Health & Nootropics Depot
Only thing I see in common between vitamin C and borate is their reductive capacity.
True. I didn't think to compare what borate and ascorbic acid had in common.
We have no literature to back this up, also very unlikely.
Yeah, you are likely correct that it is due to ascorbic acid reducing EGCG, or preventing it from auto-oxidizing. Still, that doesn't necessarily prevent the action of EGCG as a zinc ionophore, does it? The study specifically mentions that zinc chelation was not a factor in the ACE inhibition. Isn't EGCG acting as an ionophore in its reduced form, not in its oxidized form? I was under the impression that chelation of metals like zinc by EGCG was an interaction with the 3,4-dihydroxyl group in the B ring forming a coordinate bond. That would be an interaction with the OH groups in the reduced form of EGCG, not the oxidized, or am I having a brain fart here?
I thought I had a stroke or something.
Maybe I was the one having a stroke! I definitely rambled a bit off track there, and made it way too confusing. Forget about all the shit I threw in the middle.
Also, chloroquine is not oxidized/reduced in the body.
Looking back at my comments, I see I probably caused this by saying the zinc ionophore actions of both EGCG and chloroquinone depend on redox conversion. That's my bad. That seems to be wrong. I can't say for sure exactly how chloroquine shuttles zinc into cells, and I am pretty sure EGCG chelates zinc in its reduced state. So having vitamin C there to reduce it might actually help its zinc ionophore action. If I am right about EGCG acting as a zinc ionophore in its reduced state, then vitamin C reducing it and preventing the oxidative conversion and ACE inhibition should not adversely affect the beneficial effect we were originally speaking about. But yes, if the zinc ionophore actions of EGCG depend on its redox conversion, then perhaps taking it with vitamin C would fight against that somewhat.