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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: mordoh on June 14, 2004, 07:18:46 AM

Title: extract flavonoids from plants
Post by: mordoh on June 14, 2004, 07:18:46 AM
Hello..

please help me, i need to extract flavonoids from plants
do you know of a simple protocol that i can seperate them from the plant tincture,

i also need to know how (if i cant seperate the flavonoids) i can get rid of un needed substance in the plant - like wax, oils etc .. - i heard about hexan, chloroform (are they toxic?) and Naphtha

also if you can help me by giving me a protocol of isolating catechins from green tea

one more question, what is the diffrence between extraction of herb with acetone and with ethanol ?

thanks alot , i really need answers.
Title: Re:help me please with extractions
Post by: Limpet Chicken on June 14, 2004, 01:36:47 PM
Yes, chloroform and hexane are somewhat unpleasant, chloroform can sometimes have a tendency to form phosgene (carbonyl chloride) which is really nasty, and I don't think there is much of a problem with hexane per se, but n-hexane may well be present as an impurity and it's unusually neurotoxic for a hydrocarbon.

The difference between acetone and EtOH extraction is that acetone dissolves fats and some other things (terpenes I think) better than EtOH, I use acetone quite a lot in the extraction of salvinorin A from the salvia divinorum plant  ;D

If you are going to use chloroform, it's a good solvent, you can make it by the action of a concentrated hypochlorite on acetone and then distillation  :)  but take care to add a very little aquous ethanol to retard phosgene formation and keep it out of the light during storage.

Hope this helps.
Title: Re:help me please with extractions
Post by: mordoh on June 14, 2004, 01:48:19 PM
thanks for the replay...

im kinda more intrested in a simple protcol to isolate flavonoids and catechin (from green tea) , if anyone can help me with that....

and also a way to remove un needed oils and wax from the tinctures i have... (maybe with Naphtha?)

thanks
Title: Re:help me please with extractions
Post by: Limpet Chicken on June 14, 2004, 01:58:40 PM
Chloroform is an excellent defatting agent, try making a crude extract with another solvent, filtration through filter paper, evaporation, then defatting with chloroform in a sort of two-layered process with naptha.

I can't remember the exact process, but there is a step by step guide on www.erowid.org under salvia for the extraction, and it works pretty well.  

Salvia rules  ;D
Title: Re:help me please with extractions
Post by: mordoh on June 14, 2004, 02:22:29 PM
thanks i will check it out
Title: Re:help me please with extractions
Post by: Mitch on June 14, 2004, 02:55:22 PM
check the forum rules before posting new topics in the future. Thanks in advance.
Title: Re:help me please with extractions
Post by: jdurg on June 14, 2004, 03:48:29 PM
Another thing to remember about chloroform is that it is a very potent central nervous system depressant, a.k.a. anesthetic.  If you inhale chloroform vapors it can make you very weak and tired and prone to passing out.  If there is nothing in the area to clear out the CHCl3 vapor, it can and will kill you.  
Title: Re:help me please with extractions
Post by: Limpet Chicken on June 14, 2004, 05:20:44 PM
Mitch, was posting that source on erowid agains the rules? I'm sorry if it was, but I didn't post it relating to drugs at all, it's just the only place I could think of that has the procedure for defatting that i could think of at the time, sorry  :(