On the cover: Pueraria candollei var. mirifica is a Thai medicinal plant rich in phytoestrogen isoflavones and chromenes whose biosynthetic genes remain largely uncharacterized. Suntichaikamolkul et al (on pp.64-79) discovered a cytochrome P450 (CYP81E63) that regiospecifically exhibits either 2′ or 3′ daidzein hydroxylation. In addition, CYP81E63 interacted with several enzymes related to isoflavone biosynthesis, suggesting a scheme for metabolon formation in the pathway. These findings provide compelling evidence regarding the involvement of CYP81E63 in the early step of the biosynthesis of phytoestrogen miroestrol, which will be key to discovering subsequent steps in the biosynthetic pathway.

The cover image shows a seven-year-old Pueraria candollei var. mirifica plant cultivated in a pot in Bangkok, Thailand. The tuberous root is the main source of various phytoestrogens including isoflavones and miroestrol.

Photo credit: Sudarat Kasemcholathan, Chulalongkorn University, Thailand.