MR AZIDE - 6-8-2012 at 10:32
Got some common foxgloves in the back garden, I want to see if I can isolate a small sample digoxin .
I pulled off 4 large leaves, and mashed them up, and have refluxed them with 20 ml of ethanol .
A deep green solution, containing chloropyhll, and hopefully some of the digoxin remained.
The solution cooled and went cloudy ( digoxin? precip) but as I am typing this I am filtering the solution through cotton wool to remove any
particulate stuff, and a clear yellow / green solution is collecting.
Not having done any real extraction's like this, How much digoxin is likely to be in this extract from 4 large leaves ( roughly 20 cm by 7 cm)t.?
Would adding conc HCl to the extract solution precipitate the digoxin as the hydrochloride salt?
I did add about 2 ml of conc HCl, to about 3 ml of the extract in a small TT, immediately the solution turned yellow, but it has slowly turned green
again.
It was the pre-filtered soln so if any precip was formed, it would have been disguised in the cloudiness.
I might try evaporating the extract to see if any crystals are deposited, Maybe there is not enough digoxin in the extract to precip. I dint know how
much plant matter I'd need to use.
hyfalcon - 6-8-2012 at 11:53
Let's see, is digoxin an alkaloid? If it was, I would start by drying the plant material out completely then to every 100g of plant material add 25g
of pickling lime. Put it all into a ziplock baggy and add just enough water to slightly moisten the mix into a putty and knead till thoroughly mixed.
Let it sit 1/2 hr, then put everything into a glass mason jar along with 100ml of d-limonene and shake thoroughly for 10-15min then let it settle.
After the solids settle, decant the liquid off and place it in a sep funnel with 25ml of vinegar and shake thoroughly. Allow this to separate and
decant the bottom vinegar layer off into another beaker. Repeat the vinegar wash 2 more times. Dry the vinegar off in a warm oven and collect the
(nameofalkaloid) acetate. I don't know if this procedure works on all alkaloids, I know it works on some.
mnick12 - 6-8-2012 at 12:59
I doubt you have a quantifiable amount of digoxin from two leaves,
The concentration is quite low, and there a thousands of other compounds contained in that plant. Not to mention digitoxin, digoxigenin, and others.
Once more digoxin and the like are not alkaloids, they are cardiac glycosides and extremely poisonous with high oral bioavailability. A quick peek at
the skeleton shows a steroid backbone bonded to some sugar. No where in the molecule is there a basic nitrogen capable of being protonated, meaning
that your standard A/B extraction is not going to do anything useful here.
So in short you will have a very hard time isolating any of the cardiac glycosides present in Digitalis purpurea with only 4 leaves, and standard A/B
extraction will not aid you in your efforts. Likely more sophisticated procedures are required here such as chromatography and the like. Be careful
though dying of a heart attack is not a fun way go.