I have isolated some endophytic fungi from mangrove forest and now want to extract metabolites from them on a small scale for antibacterial and antioxidant assay. For that i have grown them in 100ml potato dextrose broth for 10 days in a shaking incubator. Then the broth and biomass have been extracted by 50ml ethyl acetate twice (total 50+50=100ml) then the solvent was evaporated by rotary evaporator. After evaporation of solvent the round bottom flask of rotary evaporator was seen empty. But for my assay i need at least 1 mg extract. What can i do now? In some paper i have seen that the extracted solvent (with metabolites) was concentrated then used. But does it means con. extract + solvent or the extract remaining after complete evaporation of solvent? I am in a little bit confused with that. please give me some suggestions in this regard. Advanced thanks for your kind suggestions.
When I do extraction, I leave it in the rotavap until completely evaporated. Then I resuspend it with a small volume of ethyl acetate and transfer it to a pre-weighted glass vials. Under a stream of air, I leave it until completely dried. Weigh the glass vial again (to compare with the empty vial) and resuspend it with methanol or acetonitrile for further analysis. The extract wont be pure, so you will need an extra purification step, such as TLC. If you want, I can send you a protocol, but I recommend the papers from Lazarus group at the Univeristy of Bristol. Cheers.
Sir, Guillermo Fernandez Bunster, you are really so much helpful. It is appreciated and further helpful if you will send me the protocol and the link for some useful papers. My email: [email protected]. Again thanks for your kind answer and valuable time.
Here is one example from a paper. We started from a small fermentation and we treated it as described by Guillermo in his reply above.
https://www.researchgate.net/publication/10918724_Condensed_aromatic_peptide_family_of_microbial_Metabolites_inhibitors_of_CD28-CD80_interactions
Article Condensed aromatic peptide family of microbial Metabolites, ...
I agree with Fernandez-Bunster answer. After complete evaporation of solvent from extarct on rotar y evaporator. you might not be able to see you dried extract as the amount of extract is very low. After complete evaporation of solvent you should dissolved you extract in small amount of metahnol and transfer it in small flask and evaporate it at room temperarture. Hope fully u will get required amunt of extract for biological activity. For isolation of active molecules you can do extraction at large scale.
All the best!
Dr. M.Khan
