[dennisnguyen07]

Hi, I am taking an upper division Pharmaceutical Chemistry course. I'm having trouble explaining why Saponins are undesirable in drugs. Wikipedia and other sources online just talks about how its toxic and stuff, but that's not the correct answer. Is there something about its structure that makes it undesirable?

[Arkcon]

If you go to Wikipedia again, and look closely at the description, you can see a number of properties the saponins have that would be bad for someone to ingest.  http://en.wikipedia.org/wiki/Saponins  Try to see if you can pull some of the terms together.

[trainor]

Dennis --

That saponins are undesirable as drugs is just a viewpoint.  It might be held by certain pharmas, but one can guess a few reasons for the bias:  The old view that drugs must contain at least one nitrogen atom (must be alkaloids)...  That saponins are water soluble...  That somehow saponins don't fit into Lipinski's Rule of Five [which only applies to oral drugs absorbed by passive mechanisms]...  That saponins rip open red blood cells...  That saponins are glycosides...  That they're not food chemists who know how to deal with carbohydrates, proteins, and glycosides...  That they don't show up as hits as frequently in high-throughput screening (HTS) if their HTS is biased for lipophilic molecules (DMSO used in HTS)...  That they want to tell their investors that they've distanced themselves from traditional natural product based drug discovery [despite what they do inside the company]...  That they ignore "biopharmaceuticals" and focus instead on small molecules (saponins are hot right now as potential "adjuvants")...

Just remember, in the phytochemical universe, the diversity of glycosides is larger than the diversity of alkaloids.  I learned this last point by counting them one day.

    -- douglas