What is your protocol to quantify flavonoids?

Dear colleague it is not possible to use ascorbic acid as standard for TFC evaluation, when you extrapolate your samples results on the standard range curve, you estimate your sample content as equivalent to a known flavonoid than interacted with the aluminium chloride, so if you want to replace quercetine use another flavonoid such as rutin. Best regards.

Hicham Mechqoq thank you so much dear Hicham. What is the solvent of rutin?

Yurii V Geletii

According to method that described by Meda et al (2005).

See attached file plz.

Hello Donya Moradi, I agree with the rest of the colleagues. Ascorbic acid (AA) is not a flavonoid so it cannot be used as a reference standard for the total flavonoid (TF) assay. AA is normally used as a reference standard for the antioxidant capacity assay. As a TF standard it can be used the major flavonoid constituent in your sample as Phillip Morris suggested; however, it is a common practice to use quercetin or rutin as reference standards as mentioned by Hicham Mechqoq. In addition, the use of one of these common standards is also helpful since it allows you to compare your results with those reported in the literature.

Regards,

Rogelio.

Dear Donya Moradi , with rutin I use Methanol as solvent, Actually, Both Rutin and Quercetin are well dissolved in MeOH and water, for the other solvents I have no idea, else you can use DMSO as a dissolver, but you have to make sure you eliminate the DMSO cut-off with the blank.

best regards

Phillip Morris, I totally understand your point and agree on it. However, following that approach we cannot be using the term of total flavonoids at all, similarly to total phenols. In natural products science, as the analytical procedures get more advanced there is not need to use these "general" parameters as we have the means to know the structures of most of the chemical species present in a sample, but in other disciplines as in food sciences these terms are useful as a first approach to figure out the general picture of a sample extract or food.

Hicham Mechqoq thank you dear Hicham- Donya

My pleasure dear donya, i wish you good luck with your experiments

Hicham Mechqoq

Thank you so much,

you too.

no of course, ascorbic acid is a phenolic acid while the flavonoids is a one groupe of phenols compouds and defferent chemically.

you can use quericitin, rutin,

catechin

best regards Dhifaf Zeki Donya Moradi Harith Rajab Almosawy Ali Hassan Abood Hussein Abd Baydaa A. Hassan

No

good idea

Basically anyone using catechin as a standard for flavonoids has no idea what they are doing, and neither do reviewers who accept it.. It is just wrong . It is however an acceptable standard for total phenolics, but only when the extracts mainly contain catechins (eg wine and tea). ALWAYS, and ONLY use standards that represents the major flavonoids in the extract, otherwise quantitative results will be almost meaningless.

It is better to use flavonoids such as rutin or quercetine for Total flavonoid content, and phenols such as gallic acid.

Kind regards.

best work