HI,
I am trying to isolate the secondary metabolites of some marine bacteria using organic solvent extraction. I am going to use rotary vacuum evaporator in order to obtain the powdered form of compounds. I just want to ask while performing AST of powdered compound do i need to dissolve it in the DMSO??? Does it really that necessary to use DMSO or the solvent in which had prepared the extract would also do??
Thank you.
I agree with Vinesh that ethanol is a good solvent as long as it dissolves your sample. If only some of the material dissolves in ethanol, it might actually be an advantage. It allows you to fractionate your raw product into 2 components. What is insoluble in ethanol will be , most likely, soluble in DMSO.
The only problem with dissolving in a solvent like hexane or other water-insoluble solvents is that when you add your sample to your biological assay, the sample will stay in a droplet or layer on top the solution and not get mixed into the assay. With test tubes you can shake but with microplates you often end up with non-reproducible results.
Sandesh,
You have a number of problems.
1. DMSO is very hard to evaporate. At room temperature you can leave a sample with DMSO on vacuum for a week and still have residual DMSO.
2. Using a rotoevaporator in this instance will give you a sticky or glassy film. If you want a powder, you are probably better off freeze-drying (lyophilizing) the sample. But make sure that you sample (in water) is frozen before you begin teh evaporation procedure.
3. If you plan on doing dose-response experiments, I would suggest that you generate the powder and then dissolve that powder into DMSO. That DMSO solution is what you will use in your assays.
4. Is your sample somewhat soluble in water? That will usually give the best freeze-drying results. Even if it tends to make the water foggy when you add a solvent solution to the water, you are probably OK. It is not good for your vacuum systems to pull off large quantities of solvent.
5. A water aspirator will not provide enough vacuum to efficiently evaporate DMSO.
Hi,
I have powdered compound which was obtained from etanolic extract by using rotary vacuum evaporator. Now i am going to perform antimicrobial susceptibility test using selected test cultures. Now in order to perform AST my compound should be in the liquid state. So i do i need to dissolve it in DMSO or ethanol would also do.
Please reply.
The choice of solvent also depends on the nature of your isolated compound. You can check the following as per the nature of your compound. To extract polar compounds from plant parts, it is best to use water, ethanol methanol or butanol while for non polar compounds diethyl ether, hexane or chloroform depending on the use of the estract. I believe these will give you good result.
Polar: water, methanol, ethanol
Non-polar: hexane
For polar: 70% Methanol in water
Mid-polar: Ethyl acetate
Non-polar: Use hexane or pentane
You can also read my paper.
Good Luck!
I agree with Vinesh that ethanol is a good solvent as long as it dissolves your sample. If only some of the material dissolves in ethanol, it might actually be an advantage. It allows you to fractionate your raw product into 2 components. What is insoluble in ethanol will be , most likely, soluble in DMSO.
The only problem with dissolving in a solvent like hexane or other water-insoluble solvents is that when you add your sample to your biological assay, the sample will stay in a droplet or layer on top the solution and not get mixed into the assay. With test tubes you can shake but with microplates you often end up with non-reproducible results.
Everyone already answered all the questions. I agree with Vinesh and Joe that ethanol is suitable to be dissolved your crude extract as ethanol was used to extract. And if I guess correctly, your crude extract will not 100% soluble to ethanol as some will tend to dissolve in water or DMSO. As Joe already mentioned, you will get two parts: ethanol extract and the precipitate that you can choose to test both (by dissolve the insoluble fraction with water or DMSO) or only ethanol soluble fraction.
Please keep in mind that Dimethyl sulfoxide (DMSO) and ethanol will show effects on bacterial growth, which is an important factor to be considered, while considering reproducibility of experiments for MIC determination. See here:
https://ispub.com/IJMB/7/1/5909
Dear Sandesh, to obtain your substances as a powder I agree with Joe that freeze drying is the method of choice. Just one thing: if your compounds are not soluble in water try tert-Butanol instead, or a mixture of tert-Butanol and water. These solvent are suitable for lyophilization and in most cases this works fine to get secondary metabolites in a manageable form.
Well, I think the question is whether it is necessary to dissolve the extract in DMSO. If I am correct then I must say that it depends on the type of extract. If the extract is a soluble one then you do not necessarily have to dissolve it in DMSO. You can use simple distilled water or even ethanol as the case maybe. But if it is none-polar you may have to use the DMSO as it will enhance the dissolution of the sample without necessarily reacting with the compounds
- DMSO in pharmaceutical production
It is widely used in pharmaceutical intermediate synthesis as reaction solvent, such as, norfloxacin, ofloxacin and etc. And it is used in the preparation of berberine, and traditional Chinese medicine extraction.
- DMSO in medical treatment field
DMSO has the effect of diminish inflammation, analgesia, wound healing, diuresis and etc. It has curative effect on neurodermatitis, psoriasis, arthritis, bursitis, epifolliculitis, rheumatoid, otitis media, piles lumbar muscle degeneration and other diseases.
http://www.dmso.net.cn/product_detail_en/id/3.html
Ethanol would be better. DMSO would be hard to evaporate. Other than the above factors, the safety profile of DMSO is also important. Please see the attached file.
Regards
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