Sciencemadness Discussion Board

Questions about a novel extraction

Pyro - 7-8-2013 at 14:31

Hello,
When in the local market i came across Acmella oleracea or Szechuan buttons, I had had these once before and immediately recognized them so I bought a bunch for about 2 eur. these little buds are amazing, you chew them up and they taste quite bad, but then you whole mouth starts tingling, its amazing!

I am interested in extracting the actual components that make them interesting from the leaves with my new fancy Soxhlet extractor. The problem is that I don't know what solvent to use as it needs to be edible

The best course of action would probably be to dry and shred the leaves, then extract with ethanol. and evaporate to get an essence.

does anybody have suggestions as this is to be something food grade?

subsecret - 7-8-2013 at 14:47

I suppose you could use Everclear or vodka. Be absolutely sure that there is no contamination by toxic compounds. I'm always against preparing foodstuffs in the amateur lab.

Pyro - 7-8-2013 at 14:53

you are right about that, but my extractor and fitting condenser are brand new
though i'm not sure if ethanol will actually dissolve the products as there is not much information on the exact composition.

ElizabethGreene - 7-8-2013 at 20:00

Knowing nothing else*, I'd start with water or steam distillation first. Sniff or taste it to see if you got your target compound. (Don't swallow.) (Rinse afterwards.)** If it's in there, then do TLC to see how many compounds you have, and what solvents they "like"***.

* - I really do know nothing else, as I haven't reached amides in my textbook yet.
** - Yes; "That's what she said." </badjoke>
*** - This is the wrong word, but effectively conveys the meaning of "have compatible polarities such that they separate your target compound with reasonable measure of selectivity."

If it's not in the essential oil, then give other solvents a try. Steam distillation is my go-to tool because (I have the kit for it and) it is quick, cheap, and works for a huge number of compounds.

Wikipedia, the bastion of research, has a small amount of information on the compounds in the plant. According to the article, your target compounds are fatty acid amides. This reference is cited, but I assume I don't have access to it.

Ramsewak, R. S., et al. (1999). "Bioactive N-isobutylamides from the flower buds of Spilanthes acmella". Phytochemistry 51 (6): 729–32. doi:10.1016/S0031-9422(99)00101-6. PMID 10389272.

Cheers,
Ellie

blogfast25 - 8-8-2013 at 04:48

http://en.wikipedia.org/wiki/Acmella_oleracea#Active_chemica...

Not sure by the looks of them whether any of these are soluble in alcohol, they look very aliphatic to me.

Steam distillation is usually your first option for 'essential oils'.

This paper tells about their isolation but the abstract gives little away (paywall ahead!):

http://www.tandfonline.com/doi/abs/10.1080/14786410500246733...


[Edited on 8-8-2013 by blogfast25]

sonogashira - 8-8-2013 at 04:58

Hexane is used in a lot of commercial extractions of foodstuffs. There's no reason not to use it at home either. Indeed: "The hexane extract of A. oleraceae was the most active of the extracts and was selected for further study." From here: http://www.ncbi.nlm.nih.gov/pubmed/21953851
It was the first thing I found using google, so if it's not relevant forgive me - I have no particular interest in researching it.

[Edited on 8-8-2013 by sonogashira]

blogfast25 - 8-8-2013 at 05:02

Quote: Originally posted by sonogashira  
Hexane is used in a lot of commercial extractions of foodstuffs. There's no reason not to use it at home either.


Hexane certainly looks more like a suitable solvent than ethanol to me. Not quite sure what you'd want to do with an extract whose main merit seems to be... insecticidal activity! ;)

[Edited on 8-8-2013 by blogfast25]

sonogashira - 8-8-2013 at 05:07

Partitioning between methanol/hexane is a normal means of isolating essential oils etc., which will migrate to the hexane phase. If you have no access to hexane then lighter fluid is a suitable replacement - and consists largely of hexanes anyway.

blogfast25 - 8-8-2013 at 05:12

Quote: Originally posted by sonogashira  
[...] - and consists largely of hexanes anyway.


Really? Most lighter fluids I've seen seem a little too viscous for that.

I did some plant extraction and paper chromatography with unleaded petrol once. Of course that contains some nasty anti-knocking additives.

Metacelsus - 8-8-2013 at 05:17

If you do use hexane, make sure to get it all out of the essential oil, as it metabolizes to the toxic hexane-2,5-dione.
https://en.wikipedia.org/wiki/Hexane-2,5-dione

sonogashira - 8-8-2013 at 05:22

Quote: Originally posted by blogfast25  
Quote: Originally posted by sonogashira  
[...] - and consists largely of hexanes anyway.


Really? Most lighter fluids I've seen seem a little too viscous for that.
You have a keen eye: The can that I have (Perma fluid) says C8-C14 hydrocarbons. The boiling point is similar to n-hexane's, and certainly less than n-hepane, though.

blogfast25 - 8-8-2013 at 05:30

@sono:

Mainly C6 would be a bit too flammable, too volatile and too mobile for lighter fluids, I think. Starter fluids (for carburetted engines) would probably closer to C6 but they contain also ether, IIRW.

Still, pure n-C6 isn't hard to get.

sonogashira - 8-8-2013 at 06:57

Quote: Originally posted by blogfast25  
http://en.wikipedia.org/wiki/Acmella_oleracea#Active_chemica...

Not sure by the looks of them whether any of these are soluble in alcohol, they look very aliphatic to me.

Steam distillation is usually your first option for 'essential oils'.

This paper tells about their isolation but the abstract gives little away (paywall ahead!):

http://www.tandfonline.com/doi/abs/10.1080/14786410500246733...


[Edited on 8-8-2013 by blogfast25]

From that paper, attached:
"For each experiment 350 g of Paracress (dried aerial parts, Spilanthes acmella, Martin
Bauer GmbH, Germany) was stirred with the appropriate solvent (n-hexane, ethyl
acetate, methanol/CH2Cl2 [v/v]), filtered and the filtrate was evaporated to dryness
in vacuo. The yields of low-volatiles were 2.2, 4.0, and 11.5 g, respectively. GC-MS
analysis shows the presence of 3 by comparison using retention indices and MS spectra
from isolated and synthesized specimen."



Attachment: Paper.pdf (173kB)
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[Edited on 8-8-2013 by sonogashira]

Endimion17 - 8-8-2013 at 07:48

I can get something called (literally translated to English) "medicinal gasoline" in pharmacies. That's a mixture of pentane and hexane you can apply to skin to get rid of something like ink, nasty rat glue or whatever. It smells really nice, as you can imagine.
Judging by the molecule shape, I'd say steam distillation might ruin the compound, and ethanol might be too polar to have an appreciably fast solvent effect.

You've got a Soxhlet extractor? Good. Load it with pentane+hexane (or ether, that's a good choice, too), use lots of ice in your cooling loop to keep the loop around 0 °C and heat the solvent with a water bath.

I don't know would it be better to let the solvent evaporate and then scrape the remains into a bottle. It might be ruined by such exposure to air.
You'll undoubtedly pull other compounds into the solvent, too. Namely dyes, so you might want to do a series of thin layer chromatography, taking careful notes as you go along. :)

blogfast25 - 8-8-2013 at 12:08

Interesting result with the methanol/DCM mixture there...

sonogashira - 8-8-2013 at 12:51

Hexane seems to be the most selective though, if the insecticidal chemicals are desired:

"Freshly harvested flowers (1.13 kg) of S. acmella
were lyophilized and extracted with hexane to yield the
hexane extract (10 g), followed by ethyl acetate and
finally with methanol to yield the ethyl acetate extract
(2.1 g) and methanol extract (28 g), respectively. These
extracts were bioassayed against A. aegyptii larvae and
H. zea (corn earworm) neonates. The hexane extract
showed the highest activity."

Attachment: 729-732.pdf (133kB)
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It's a good paper. It seems very straight forward to separate
active from inactive components, and a soxhlet extraction
using hexane would be suitable in place of their extravagant
"2 x 4 litres"! :D


[Edited on 8-8-2013 by sonogashira]

Pyro - 8-8-2013 at 16:51

Blogfast, these plants completely numb your mouth! I chewed on a few buds and flt nothing in my mouth for ages, I even stuck a pin in my gums and had no feeling, that's why I need a ''safe'' solvent. since I don't have hexane (Shame on me!) i'll use ether. but it's also just a chance to try out my new toy :)

@Endi:I have a 500ml soxhlet from laboy.

I am currently on holiday so for now ill dry out then leaves, then once at home I can try to extract them.
thanks for all the help and i'll keep you posted

sonogashira - 9-8-2013 at 02:57

Quote: Originally posted by Pyro  
I even stuck a pin in my gums and had no feeling
How long does it take for the numbing-effect to dissipate?

[Edited on 9-8-2013 by sonogashira]

[Edited on 10-8-2013 by sonogashira]

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Pyro - 9-8-2013 at 04:17

it depends how many you eat, the total numbness lasted for a few mins, then there was a tingling that lasted a good half hour.

blogfast25 - 9-8-2013 at 08:38

Quote: Originally posted by Pyro  
it depends how many you eat, the total numbness lasted for a few mins, then there was a tingling that lasted a good half hour.


In that case I much prefer these so-called 'magic berries': after chewing them, lemons taste like oranges... allegedly.