The assays of phenolic/flavonoid contents are based on the similar principles as antioxidant assays, but they have different sensitivities to the same phenolic/antioxidants. Therefore, the values obtained from the same sample using different assays are different.

Thank you sir. Sir could you please elaborate on this

Without knowing the details, the simplest would be:

TFC/TPC measures the amount of water soluble antioxidants, while DPPP soluble in ethanol

The plant extract was prepared using methanol. The same methanolic plant extract has been used for TFC, TPC measurement and for DPPH radical scavenging activity

Antioxidant content is measured as the rate of consumption of the reactive species of the assay. The rates depend on the solvent and pH. Some phenolics might not react with DPPP in alcohol, but react with Mo(VI) in water and vide versa

First, the method for determining the TPC and TFC as well as the DPPH assay needs to be checked whether everything is correct and if there are no errors that cause erroneous results.

The second possibility is that the dominant TPC and TFC compounds in the leaves are less active in donating electrons to DPPH free radicals, There may be steric hindrance of those dominant molecules. Whereas in the roots, although the number is less, they are more involved in donating electrons (having a higher affinity to act with the DPPH free radical). The type and molecular structure of flavonoids and phenols greatly determine the DPPH free radical scavenging activity.

Great. Thank you Harto Widado sir