I have defatted my plant material and then prepare ethanolic extract.This extract was then fractionated with Chloroform, Ethyl-acetate and n-Butanol?Then i perform anti- microbial and antioxidant activity on fractions and i found ethyl-acetate and butanol fraction to be more active than others.What should i do from now ?
Should i go for LC-MS or NMR or go for HPTLC fingerprint ?Please help me to proceed further?
Hi, I think when it is possible please analyze it with LC-MS/MS, if you have data (HR)MS of your compounds in the extracts, you can predict the chemical structure of your compounds by using some on line free MS data bases such as Metfrag, Metlin, MassBank, mzCloud, CFM-ID etc, if your compounds are known-compounds, it will be listed in those data bases, for confirmation I think you should compare with authentic standards, or by measuring its NMR (1D/2D)
Since the extract is probably still a complex mixture, I'd run LC-MS. My opinion is that NMR of the extract will see a mixture of different compounds, possibly related, and it will be difficult to determine which compounds are in the mixture by NMR.
In my opinion LC/MS is the proper one. After doinig analysis on LC/MS in the MS database You can check the compounds and then making standard curves of selected compounds and calculate their amount. Finally, you can find some correlation between antioxidant potential and amount of these compounds. in each fractions.
You can carry out phytochemical screening using the method described by Harborne, 1985 to determine the class or type of phytochemical present in the extract. Then you can isolate the compound you want. There are different methods for isolation of phytochemicals such as flavonoids, alkaloids, etc. After isolation, you purify the isolate and then characterize by using NMR, IR and MS..
I this helps. Best of lucks.
Hi, at our Lab, if we have a large amount of fractions, we did usually column chromatography to isolate the compound(s), but if we have only small amount of fractions we did TLC-preparative and or HPLC preparative. For optimizing the separation conditions (especially mobile phase) we used TLC and HPLC. Best regards
Thanks Sir Gunawan, bT we have no standard to compare..what should i do?.should i directly proceed for LC-MS?
Hi, yes I think you can do LCMS. By LCMS you can get data of molecular ions and Molecular formulas; Molecular ions can be confirmed using their possible adducts, and molecular formula can be confirmed by their isotope pattern. After you have all the MS data, you can predict the chemical structure by using free on line MS data bases such as Metfrag, Metlin, MassBank, mzCloud, CFM-ID or others. Best regards
It is better to make HPLC-DAD optimization before doing LC-MS, but it is not mandatory. LC-MS is very informative for preliminary examination of active extracts or fractions. If you have an access to HRMS and MS/MS you will get additional information.
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