Hexane:Ethyl acetate solvent system is best for it.

Dear Asekunowo

Follow the attached threads for information on the subject. I am attaching articles on flavonoids isolation.

https://www.researchgate.net/post/What_is_the_best_way_to_separate_the_monoterpenoids_from_a_whole_essential_oil2?_tpcectx=profile_answers

https://www.researchgate.net/post/How_to_isolate_terpenes_and_sesquiterpenes_from_essential_oil?_tpcectx=profile_answers

https://www.researchgate.net/post/Which_is_the_best_solvent_for_the_extraction_of_the_polar_organic_compounds_from_herbal_plant?_tpcectx=profile_answers

https://www.researchgate.net/post/Is_petroleum_ether_good_for_terpenes_extraction?_tpcectx=profile_answers

https://www.researchgate.net/post/Hos_do_I_isolate_the_major_components_of_essential_oils?_tpcectx=profile_answers

Thank you very much for your useful suggestion, I appreciate you all.

Best Regards

Dear Asekunowo

A similar question was asked by Islam. Follow the thread for more answers.

https://www.researchgate.net/post/How_can_I_purify_only_flavonoids_from_medicinal_plants_extract_Have_any_specific_solvent_to_use_in_isolation_CC_TLC

If it is a mixture containing both types of compounds you can dissolve the mixture in EtOH or MeOH and do partition with hexane, most of the tepenes will move to hexane layer and  flavanoids which are comparatively polar will retained in the MeOH fraction.

Dear Asekunowo, you didn't say what solvent have you used to isolate terpenoids and flavonoids, did you work according Priyani said?. I agree with him. Extract them using MeOH and then make a partition with hexane to separate them from the mixture. The other way is use hexane or petroleum ether to extract the terpenoids, then use dichloromethane and finally methanol, to extract the flavonoids. The first one can extract the aglycons and the methanol the more polar flavonoids as glycosides.

Olga Lock has made a good suggestion Asekunowo can try that method too.

Thanks Olga and Priyani. I did extract with MeOH, partitioned with hexane, DCM, ethylacetate and n-butanol. I  want to know how to isolate terpenoids from the hexane fractions. I will appreciate hints on how to identify terpenoids and isolate them from the hexane fraction. Regards

The best method for identification of tepenoids is use of gas chromatography with Flame ionization detector and GCMS with column similar to carbowax 20M. Isolation of tepenoids in hexane fraction using silica column will be difficult and therefore I suggest you to use a Sephadex LH20 in which separation is based on size of the molecule not the polarity. Hope these hits help you to solve the problems.

I would prefer to use a Silicagel CC starting with pure hexane and then increasing the polarity with dichloromethane or maybe later on with methanol. But anyway, Silicagel or Sephadex LH 20 are the most common way for many of the Phytochemical constituents of plants. Good luck

Depending on the extract you want to start with, for dichloromethane extract which will contain must of the terpenoids, you can use silica gel eluting with N-hexane then gradual introduction of ethyl acetate gradiently. then methanol.Most of the terpenoids will be eluted before you reach 100% ethylacetate, except if they are glycosylated. which of course they will be  in the methanol extract.  Most flavonoids will be in the the acetate and n-butanol fraction from the methanol extract, you can start with sephadex LH-20 and for highly  glycosylated flavonoids   you can use reverse phase silica gel column chromatography  or HPLC.

For good extraction and yield you should use  dichloromethane for terpenoids. Gel filtration chromatography silica gel elution with N-hexane will be most possible option.  For separation/ extraction you can use ethyl acetate and methanol, because EA  extract more than 95% of terpinoids from the extract. You can extract out carbohydrate based prpducts by using methanol . From the methanol extract use acetate and n-butanol and run it on sephadex LH-20 preparatory column you can easily separate glycosylated flavonoids.  A reverse phase silica gel column chromatography or HPLC also provide 98% yield of flavanoids.

I appreciate all your suggestions, Regards!

Check this informative link on isolation of phytochemicals:

http://www.slideshare.net/rahulbs89/extraction-of-plant-contituents

Thank you Rao for the link, quite informative. Regards