Why natural polyphenols (like proanthocyanidins from berries) decrease their antioxidant activity in a lipid environment? vs an aqueous environment?
I know that existing research suggests that the lipid solvent lowers polyphenol antioxidant activity. But why? It is because their favored the prooxidation of lipids?
Thanks guys.
Dear Jimena, there are many answers to this, but the antioxidant capacity methods should not be ignored. The antioxidant capacity of bioactives is highly dependent upon their medium; so the solvents of the method, molecules (hydrophilic or lipophilic), radical type, and so so on have a direct influence on the antioxidant measurement. Therefore, different methods such as DPPH, ABTS, ORAC, CUPRAC may reveal variate results even for a unique substance.
Hello,
The decrease in antioxidant activity of natural polyphenols in lipid environments is attributed to several factors. Polyphenols are more soluble in aqueous environments, resulting in reduced bioavailability in lipid-rich environments. This reduces their ability to interact with and scavenge free radicals in the lipid phase, resulting in a decrease in their overall antioxidant activity. Additionally, polyphenols can undergo oxidation reactions in the presence of lipids, leading to the formation of less active or pro-oxidant compounds. Lipids can also interfere with the absorption and distribution of polyphenols in the body, forming complexes with polyphenols, further reducing their bioavailability and limiting their ability to exert their antioxidant effects. The effects of polyphenols on lipid oxidation depend on the specific type of polyphenol, the lipid environment, and the reaction conditions. While some polyphenols may have pro-oxidant effects in certain contexts, others may still exert antioxidant effects in lipid-rich environments.
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