Supplements with effect on aromatase enzyme CYP19

Supplements that can INCREASE the activity of aromatase enzyme

1. Ginseng (ginseng refers to Panax ginseng C. A. Meyer) root
Ref: US Patent US 20070041996 A1

2. Green Tea
Ref:
Chronic Green Tea Consumption Decreases Body Mass, Induces Aromatase Expression, and Changes Proliferation and Apoptosis in Adult Male Rat Adipose Tissue.
J. Nutr. November 2008 vol. 138 no. 11 2156-2163

It is stated in this paper that green tea also reduced testosterone levels and increased estradiol levels. This is an in vivo study done with oral administration of green tea infusion equivalent to human consumption.

Supplements that can DECREASE the activity of aromatase enzyme

1. Ginkgo biloba extract

Ref: 
Antiestrogenic activities of Ginkgo biloba extracts.
Oh SM, Chung KH.
J Steroid Biochem Mol Biol. 2006 Aug;100(4-5):167-76.

2. Cigarette smoking/nicotine

Ref:
J Enzyme Inhib. 1990;4(2):187-200.
Aromatase inhibitors in cigarette smoke, tobacco leaves and other plants.
Osawa Y1, Tochigi B, Tochigi M, Ohnishi S, Watanabe Y, Bullion K, Osawa G, Nakabayashi Y, Yarborough C.