I have a marine organism. When I conducted cold extraction for it, I got crude extract for non-polar to polar solvents for around six different solvents. When I tried to dissolve these crude extracts in DMSO for anti-microbial activity, the crude extract for lower concentration (50mg/ml) was dissolved nicely, unlike 100mg/ml or 200mg/ml which did not dissolve properly. Instead, a whitish colored tissue degraded and a sort of foamy substance formed in the top layer and middle layer of DMSO with undissolved crude extract, and in the lower layer with the dissolved crude extract. It happened with acetone and ethyl acetate extract. Hexane got dissolved properly. Ethanol and methanol partially dissolved, where chloroform only got 20% dissolved. I tried for warm extraction using soxhlet. Unlike in cold and hot extraction using hexane crude, I got the same whitish colored tissue degraded foamy substance even without dissolving in DMSO. For other crude extracts only minimal amount of whitish colored tissue degraded foamy substance appeared. I still need to try with ethanol and methanol.
I am in desperately in need of your help. I have attached some photos.
Hai Dear Gowri Shanker,
I am glad to know about your research in the field of Marine Natural Products, It might be the salt content, Did you removed the salt and water content by adding Sodium Sulfate with Chloroform, after adding this shake well, and filter the crude extract and try it. We are following the same procedure in my lab.
Good luck
The whitish substance could be proteins. I would suggest you to not dissolve initially in DMSO. Try various solvents such as ethanol, methanol, diethylether, chloroform, dichloromethane. You can also try dissolving some in water. Once the antimicrobial test is successful, purify it and at the last step try dissolving in DMSO.
Thank you satheesh for your info..i din remove the salt i have just washed the organism with force tap water and with distilled water..if you can provide any reference for removing salt content from the dried sample or from the wet sample if possible..it will be a great help for me..
Lekha mam the whitish colored tissue degraded foamy substance did not happen to be occurred in cold extraction for hexane..yesterday i tried for ethanol and methanol using soxhlet apparatus,..i got lots of crystal salts and its watery..but it never happened while using cold extraction.. whitish colored tissue degraded foamy substance got a thick substance when i tried to dissolve it in water..
The previous answers already touched on this, white precipitate is usually both, inorganic but also organic salts. Even if you wash your specimen, these salts stem from the intracellular and precipitate due to their elevated concentration in low polarity solvents. Anything that foams is usually proteinaceous material or lipid-type of stuff. As the others have said, desalting an extract via reversed-phase SPE is a good start, equally important is to remove lipids and other fats with hexane. Only do this if you don't expect any compounds of interest in these very apolar extracts. Sometimes warming your concentrated extract will dissolve a good deal of the precipitates. Hope this helps.
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