Trends in Plant Science
Research NewsMolecular ‘pharming’ with plant P450s
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Isoflavone synthase
Many plant secondary metabolites are derived from the phenylpropanoid pathway, including lignin, tannins, anthocyanins and many phytoalexins. Isoflavones are produced via a branch of the phenylpropanoid pathway. Taxonomically they are limited primarily to legumes, in which the first committed step in biosynthesis is catalyzed by a P450, isoflavone synthase (IFS)7. IFS converts the flavanone substrates liquiritigenin and naringenin to the isoflavones daidzein and genistein, respectively (Fig. 1
IFS metabolic engineering
Armed with the gene for IFS, researchers could now demonstrate the potential for engineering isoflavone production in plants normally lacking IFS (Ref. 1). Arabidopsis does not have IFS and does not make isoflavones, but it does produce the IFS substrate naringenin, which is normally involved in the production of kaempferol and quercetin glycosides, as well as anthocyanins and condensed tannins11. Arabidopsis plants transformed with the soybean IFS gene driven by a strong constitutive promoter
Isoflavones as phytoestrogens
Evidence that isoflavones could act as phytoestrogens was available in the 1940s when sheep grazing on clover with high levels of formononetin was linked to sheep infertility. The compound causing the problem was traced to daidzein, which is produced from formononetin in the sheep rumen12. Isoflavonoids generating the most widespread medical interest today include daidzein, genistein and coumestrol, as well as isoflavone metabolites such as equol (Fig. 1). It is thought that the proposed
Phytoestrogens and hormone-related disorders
The observed effects of phytoestrogen consumption in animals demonstrate the potential efficacy of these compounds, and have generated interest in the use of phytoestrogens for the treatment and prevention of hormone-related disorders in humans15. The potential of phytoestrogens is supported by a correlation between east Asian societies where soy is a primary foodstuff, and reduced incidence of heart disease, osteoporosis, breast cancer, prostate cancer and menopausal symptoms in comparison
Phytoestrogens and infants
Many breast-milk substitutes containing soy have significant levels of daidzein and genistein, such that the daily intake of isoflavones in 4-month-old infants fed on substitutes based on soy protein would be approximately ten times that which has estrogenic effects in adults. Moreover, the combined concentrations of genistein and daidzein in plasma from 4-month-old infants fed soy formula were more than 10 000 times greater than typical infant plasma estradiol concentrations18. Although these
Phytoestrogen ‘nutraceuticals’
Our increasing awareness that compounds found in food can function in capacities well beyond simple nutrition has bolstered the idea that various foods might have an impact on conditions previously thought to be unrelated to diet. This has resulted in an explosion in the number of phytoestrogen dietary supplements being marketed to consumers. If the information currently available is representative of the actual potential for dietary treatment of hormone-related conditions by phytoestrogens,
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Cited by (19)
Comparison between tumors in plants and human beings: Mechanisms of tumor development and therapy with secondary plant metabolites
2019, PhytomedicineCitation Excerpt :Flavonoids belong to the three main classes of plant secondary compounds, besides isoprenoids and alkaloids. They are known for their support of human health as radical scavengers (Humphreys and Chapple, 2000). In plants, flavonoids play an ambiguous role.
Health Perspectives of an Isoflavonoid Genistein and its Quantification in Economically Important Plants
2018, Role of Materials Science in Food BioengineeringModified nicotine metabolism in transgenic tobacco plants expressing the human cytochrome P450 2A6 cDNA
2005, FEBS LettersCitation Excerpt :CYP1A1 from rat mediated an enhanced chlortoluron resistance when introduced into the tobacco genome [11,12], proving that recombinant mammalian P450s have the potential to influence the metabolism of xenobiotics in plants. Also the modification of biosynthetic pathways in plants is an enormous challenge since an improved secondary metabolism would increase the value of a crop or medicinal plant [13–15]. There are numerous attempts to influence the formation of secondary compounds in plants by genetic engineering with some employing the shuffling of P450s between different plant species.
Discovery of isoflavone phytoalexins in wheat reveals an alternative route to isoflavonoid biosynthesis
2023, Nature Communications