68 ms·

Polyphenols? Far too often you see inexperienced medical researchers who stumble across a polyphenol while screening natural products and think they've found a

Polyphenols? Far too often you see inexperienced medical researchers who stumble across a polyphenol while screening natural products and think they've found a viable lead compound. This class of compounds is an unselective binder (plants have evolved tannins to denature any protein, including those in fungal plant pathogens) and impossible to elaborate. The SGLT inhibitors developed from phlorizin are an exception. You'd expect better from UCSD, though.

gus_massa 9y ago
From the research article: > We previously developed a high-throughput screening CellTiter-Glo ATP bioluminescence-based assay to assess antiparasitic activity [48], and used this assay to test compounds 1–9 against the trophozoite stage of E. histolytica, G. lamblia, and N. fowleri. Compounds 1–6 displayed dose response antiparasitic activity against all three pathogens by reducing the culture density by 50% (EC50) compared to untreated trophozoite cultures (Table 3). If I am translating it correctly, they only tested this in vitro (not in rats, not in humans). So, as you say, this may not be useful to cure us. Relevant xkcd https://xkcd.com/1217/ https://xkcd.com/1217/
- HarryHirsch 9y ago
  It's grape season! I've got a few scuppernog vines (that's the grape native to the US, Vitis rotundifolia) in the yard. They are bearing grapes plentifully. Scuppernogs have a thick skin, much thicker than the European kind (V. vinifera), with astringent flavour (that's polyphenol tannins) . When you look at the surface closely you see little corky spots, where the hypersensitive response took place, a defense mechanism in plants against fungal infection. The tannins denature cellulase enzymes that are secreted by fungal hyphae in their attempt to invade cells, and cork is dry and just plainly indigestible. Indeed, scuppernogs have an excellent reputation for disease resistance. The xkcd is very relevant, also for grapes.
kurthr 9y ago
Yes they stick to everything, and we have no clear idea on a mechanism. As drug candidates few in pharmaceutical development would want to work with them. http://blogs.sciencemag.org/pipeline/archives/2014/06/18/how_polyphenols_work_perhaps http://blogs.sciencemag.org/pipeline/archives/2014/06/18/how...

gus_massa 9y ago

From the research article: > We previously developed a high-throughput screening CellTiter-Glo ATP bioluminescence-based assay to assess antiparasitic activity [48], and used this assay to test compounds 1–9 against the trophozoite stage of E. histolytica, G. lamblia, and N. fowleri. Compounds 1–6 displayed dose response antiparasitic activity against all three pathogens by reducing the culture density by 50% (EC50) compared to untreated trophozoite cultures (Table 3). If I am translating it correctly, they only tested this in vitro (not in rats, not in humans). So, as you say, this may not be useful to cure us. Relevant xkcd https://xkcd.com/1217/ https://xkcd.com/1217/

HarryHirsch 9y ago
It's grape season! I've got a few scuppernog vines (that's the grape native to the US, Vitis rotundifolia) in the yard. They are bearing grapes plentifully. Scuppernogs have a thick skin, much thicker than the European kind (V. vinifera), with astringent flavour (that's polyphenol tannins) . When you look at the surface closely you see little corky spots, where the hypersensitive response took place, a defense mechanism in plants against fungal infection. The tannins denature cellulase enzymes that are secreted by fungal hyphae in their attempt to invade cells, and cork is dry and just plainly indigestible. Indeed, scuppernogs have an excellent reputation for disease resistance. The xkcd is very relevant, also for grapes.

kurthr 9y ago

Yes they stick to everything, and we have no clear idea on a mechanism. As drug candidates few in pharmaceutical development would want to work with them. http://blogs.sciencemag.org/pipeline/archives/2014/06/18/how_polyphenols_work_perhaps http://blogs.sciencemag.org/pipeline/archives/2014/06/18/how...