Then they’re laid out for a period of time to let the oxidation set in. Enzymes like polyphenol oxidase speed things up, quickly clumping the polyphenols inside -- like our four catechins ...

Feeding with tea catechins for 1 month significantly increased acyl-CoA oxidase and medium chain acyl-CoA dehydrogenase mRNA expression as well as β-oxidation activity in the liver.

Therapeutic effects of green tea polyphenol (-)-Epigallocatechin-3-gallate (EGCG) in relation to molecular pathways controlling inflamamtion, oxidative stress, and apoptosis. https://pmc.ncbi.nlm ...

It’s all about the chemistry. Adding lemon can enhance the flavour and enjoyment of tea, and change its colour, but its best not to expect any extra boosts to your health.