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WalkingTalker t1_j8bptsr wrote

Abstract looks like a pretty well run study with lots of candidates tested:

Evaluation of 1867 extracts and 18 compounds for virus spike protein binding to host cell ACE2 receptors in a SARS-CoV-2 pseudotyped virus system identified 310 extracts derived from 188 species across 76 families (3 fungi, 73 plants) that exhibited ≥ 50% viral entry inhibition activity at 20 µg/mL. Extracts exhibiting mammalian cytotoxicity > 15% and those containing cardiotoxic cardiac glycosides were eliminated. Three extracts were selected for further testing against four pseudotyped variants and infectious SARS-CoV-2 and were then further chemically characterized, revealing the potent (EC50 < 5 µg/mL) antiviral activity of Solidago altissima L. (Asteraceae) flowers and Pteridium aquilinum (L.) Kuhn (Dennstaedtiaceae) rhizomes.

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CocktailChemist t1_j8cctne wrote

Will be interesting to see what the active compounds are and what their prevalence in the extracts was. Because if you assumed that they were pure compounds 5 ug/mL is probably somewhere in the 10 uM range, which is not what you’d hope for from a potential hit.

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SaltZookeepergame691 t1_j8colfg wrote

Aye, Figure 3 showing the efficacy vs remdesivir is basically all we need to see. Huge difference in observed 'potency', even accounting for their presentation of different units... and this against a drug that is far from optimal anyway.

>Because if you assumed that they were pure compounds 5 ug/mL is probably somewhere in the 10 uM range, which is not what you’d hope for from a potential hit.

Indeed. 99% of SciRep papers reporting successful anti-SARS-CoV-2 activity fall over completely at the first glance of the concentrations used/required.

Guarantee no one is gonna want to/be physiologically able to consume enough of these extracts to achieve 10 uM lung tissue concentrations, even if these extracts are absorbable, survive the GI tract, accumulate in lung, and don't kill or maim you first.

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CocktailChemist t1_j8ei0qg wrote

I’ll give them some wiggle room since it’s entirely possible that some minor but extremely active constituent is giving all the response (this has happened to me where I remade a compound that turned out to be inactive compared to previous preparations because it was too pure and didn’t have the active impurities of what had been made before), but it is useful to have that perspective about the potential limitations of what they’re seeing. Such are the challenges of natural product chemistry.

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