This can happe when- the active compound has stereochemistry and u end up isolating the other isomer; when the metabolite of the compound is active, invivo; when other lesser known compounds act as synergists...

It is quite common that some coextracts act as synergist of the active substances, even if the mechanism is often unknown (and likely different case by case)..

I believe that you are not the only person scratching their head about this. A number of possible reasons may be behind this:

- Often, phytochemicals act together to enhance efficacy, bioavailability or stability (e.g. phenolics in St. John's Wort are known to protect hypericin from oxidation)

- Stability: you may have encountered degradation during the isolation process

- Different classes of compounds may act on different targets, so you'll obtain better results with a mixture

There are other reasons which may play a role. I recommend a paper by Eder and Mehnert (Pharmazie 1998, 53: 285-293), which gives a good review on the topic.

Hello Stefan,

Thanks for the info on the paper, will have a look at it.

To all others also thanks for giving their valuable suggestions.

Regards,

Dear Dr. Preetha

I am agree with all of them, I am have the same results with the anti-tumor activity of the extract and some of the isolated flavonoids, the extract was more potent than the isolates, and this may be attriputed to the synergists, and may be due to the presence of other compounds in the total extract that may be not isolated (other than the flavonoids).

Please, I will need you help to get a copy of the article of Eder and Mehnert (Pharmazie 1998, 53: 285-293) which have been recomended by Stefan.

Regards

Magdy

Hello Magdy,

I have mailed you some queries, hope you have received it.

Then, can you help me in identifying the list of anti-tubercular plants you had sent me on my request that is, are these plants mentioned somewhere in literature of Egypt as possessing anti-tubercular properties ? If so where can I get the details ?

Regards and thanks in advance,

Preetha Anil

Dear Dr. Preetha

Thanks for your last queries, for the list of the plants with anti-tubeculosis, the plants have been mentioned in the book `African Traditional Medicine; A Dictionary of Plant Use and Applications` it mentioned the plants that have been used in the folkloric medicine by the Africans. Just tell me which plant exactly you need and I can help you with the old method they were use to treat that disease.

Regards

Magdy

Dear Dr. Magdy,

These are the plants for which I need reference in literature. If you get the details please mail at [email protected]

1- Acacia latistipulata

2- Calotropis procera

3- Albizia amara

4- Albizia antunesiana

5- Aloe secundiflora

6- Anchomanes difformis

7- Aporrhiza paniculata

8- Ardisia staudtii

9- Ardisia zenkeri

10- Asclepias fruticosa L.

11- Asclepias physocarpa

12- Asparagus striatus

Thanks for the name of the book.

Regards,

Dear Dr. Preetha

Can you help me more regarding the kind of the references you need for the plants, is it references for its use as antituberclosis? if so I am not sure that these plants has been investigated for this activity before, it has been mentioned in the book as folkloric uses. I hope that you can help me more to see what can I do for you.

Regards,

Magdy

Dear Dr Magdy,

Yes, references to show that they are anti-tubercular, but in case they are mentioned in the above book that is enough, I will see to that.

Thank you for the prompt response.

Regards,

Dr Preetha Anil

Yes, sometimes synergistic activities are present in extracts and when isolated, these actions may not be there and that is why they are not effective as that of the extract.