**6.2 Transcription factor Nrf2**

Transcription factor Nrf2 (Nuclear factor E2–related factor 2) binds to and induces activation of the ARE. Nrf2 was first isolated by an expression cloning procedure using an oligonucleotide containing the NF-E2 DNA binding motif as a probe to screen for closely related proteins (Moi et al., 1994). Nrf2 belongs to the cap-and-collar family of basic region– leucine zipper transcription factors, and is an essential component of the ARE-mediated transcriptional machinery. It has been shown that Nrf2 mediates both the basal and inducible activity of the ARE, and the loss of Nrf2 results in a profound reduction in the enzyme activities of NQO1 and certain GST isoenzymes (Itoh et al., 1997). These observations also correlate well with the ubiquitous expression of Nrf2 at steady-state levels

The Botanical Extract Feverfew PFE Reduces

Fig. 4. Feverfew PFE induces activation of the ARE promoter.

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0

0

50

100

150

**% Increase in Nrf2 activity** 

**over control**

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300

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100

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**ARE Promoter**

**% Change over Control**

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Fig. 5. Feverfew PFE activates the Nrf2 transcription factor.

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enhanced the nuclear translocation of Nrf2 by more than 70%.

In order to analyze the effects of Feverfew PFE on the transcription factor, Nrf2, a TransAM ELISA was utilized. Primary human keratinocytes were treated with Feverfew PFE or Sulforaphane for 24 hr, following which the nuclear and cytoplasmic cell lysate fractions were separated. Translocation of Nrf2 was analyzed in the nuclear fractions. Feverfew PFE

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**Control Feverfew PFE (10ug/mL) Sulforaphane (10uM)**

**Feverfew PFE (10μg/mL) (10μM)** 

DNA Damage and Induces DNA Repair Processes 539

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**Control Feverfew PFE (5ug/mL) Sulforaphane (10uM)**

**Feverfew PFE (5μg/mL) Sulforaphane (10μM)** 

233

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in various tissues and cell lines (Nguyen et al., 2004). As a result, the function of Nrf2 and its downstream target genes are vital for protection against cellular damage induced by oxidative stress or chemicals. Several studies have shown that Nrf2 knockout mice having decreased levels of phase II detoxification enzymes and antioxidant proteins are highly sensitive to cytotoxic electrophiles compared to their wild-type littermates (Lee and Johnson, 2004; Leung et al., 2003). The upregulation of protective detoxification and antioxidant genes by Nrf2/ARE pathway can synergistically increase the efficiency of our cellular defense system.
