EGCG (epigallocatechin gallate) and catechin are both flavonoids found in green tea, but they have several key differences:

Chemical Structure

• Catechin is a simpler molecule with two benzene rings (A and B) and a dihydropyran heterocycle (C ring) with a hydroxyl group on carbon 32.

• EGCG is a more complex molecule, being a galloylated form of epigallocatechin. It has an additional gallate group attached to the C ring26.

Prevalence in Green Tea

• EGCG is the most abundant catechin in green tea, accounting for approximately 50-70% of the total catechin content19.

• Catechin is present in smaller amounts compared to EGCG in green tea9.

Biological Activity

• EGCG is generally considered the most biologically active catechin in green tea, with potent antioxidant and anti-inflammatory properties6.

• Catechin, while also beneficial, typically shows less potent effects compared to EGCG in various studies5.

Antioxidant Potential

• EGCG demonstrates stronger antioxidant activity compared to catechin4.

• The antioxidant potential of catechins is related to their chemical structure, with EGCG's additional gallate group contributing to its enhanced activity2.

Stability and Bioavailability

• EGCG tends to be less stable in certain conditions compared to catechin7.

• The bioavailability of EGCG and catechin can differ, with EGCG often showing higher plasma concentrations after green tea consumption9.

In summary, while both EGCG and catechin are beneficial compounds found in green tea, EGCG is more abundant, structurally more complex, and generally exhibits stronger biological activities compared to catechin.