numerous studies can be found using Google Scholar, keywords: tea catechins polyphenols mao-b inhibitors
catechins (aka 'tannins') can be found in chocolate, wine, other fruits & veggies http://www.o-cha.net/english/conference ... II-311.pdf
Results of this investigation indicate that most of samples can attenuate peroxide production by inhibiting the deamination of monoamines as a scavenger, regardless of the methods o f processing and provinces of cultivation.
It was also shown to inhibit non-competitively both MAO-A and MAO-B with the IC50 so values. It is concluded that some Chinese green teas may be useful in the prevention/treatment o f neurodegenerative diseases
relating to in vitro MAO inhibitory activities. The structure-activity relationship examination should be followed
for further research..
There is a co in Japan that produces a concentrated extract of green tea with higher levels of these polyphenols thought to be beneficial.