**5. Botanical extracts | Feverfew PFE as an antioxidant**

Feverfew (*Tanacetum parthenium*) is a plant that has been used as a medicinal herb for centuries throughout Eastern Europe and more recently North America. Traditionally, it was used for its anti-inflammatory properties to treat migraine headaches, fever, and arthritis. Additionally, feverfew has shown to exhibit powerful antioxidant activity. Although feverfew leaves contain skin irritating compounds called parthenolides,

The Botanical Extract Feverfew PFE Reduces

Fig. 1. Feverfew PFE inhibits Reactive Oxygen Species.

0

100

200

**Reactive Oxygen**

**Species**

Feverfew PFE (g/ ml)

**(M.F.U)**

300

400

**5.2 Feverfew PFE inhibits cellular inflammation** 

9.4 μg/ml respectively (Martin et al., 2008).

skin cancers (Mueller, 2006).

protect skin from oxidative stress that could result in DNA damage.

DNA Damage and Induces DNA Repair Processes 535

those in the no-smoke exposed control (Martin et al., 2008). Through free radicals scavenging activity and preserving endogenous antioxidant levels, Feverfew PFE may

**\* \***

UT 0 100 50 25 12.5 6.25 3.1

UV Exposure

**\***

**\***

**\***

**\***

UV irradiation has been shown to induce the release of various inflammatory cytokines such as IL-1α, IL-6, TNF-α, that are involved in the pathophysiology of UV-induced inflammation (Aubin, 2003). Inflammation has been linked to epithelial skin tumors, and antiinflammatory drugs are being studied for the prevention and treatment of non-melanoma

Feverfew PFE can reduce the release of pro-inflammatory mediators through inhibition of enzymes involved in production and regulation of inflammation. Feverfew PFE directly inhibited the activity of 5-lipoxygenase (5-LOX), phosphodiesterase-3 (PDE3) and phosphodiesterase-4 (PDE4) with IC50 values 11.8 ± 4.8 μg/ ml, 35.2 ± 12.3 μg/ml and 20.8 ±

Feverfew PFE also reduced PGE2 secretion from human skin equivalents and inhibited p38 MAP kinase activation in vitro (Martin et al., 2005). Feverfew PFE had no direct effect on COX-2, this indicates the mechanism of inhibiting PGE2 formation may be upstream to COX-2. Human skin equivalents were pretreated with Feverfew PFE and then thoroughly washed prior to UV exposure. In the absence of treatment, UV irradiation induced inflammatory cytokine release. Pretreatment with Feverfew PFE significantly reduced UVinduced cytokine release by more than 60% over placebo treated control skin equivalents. Topical application of Feverfew PFE was examined in an investigator blinded, placebocontrolled clinical study for their effect on UV-induced erythema. Subjects were exposed to UVB irradiation of 0.5 to 1.5 MED (Minimal Erythema Dose), followed by daily applications

purification processes are available to create feverfew parthenolide-free extract (Feverfew PFE) which does not produce skin irritation and is free of sensitization potential (Kurtz, et al., 2005).

#### **5.1 Feverfew PFE reduces UV and external aggression induced reactive oxygen species formation**

Reactive Oxygen Species are produced in skin following UV irradiation and is a major mediator of oxidative damage to the skin (Pathak and Stratton, 1968). Hydrogen Peroxide (H2O2 ) and peroxyl radicals are produced in skin following UVB irradiation (Stewart et al., 1996) and can induce oxidative damage to DNA and other cellular constituents. Singlet oxygen can be generated from the action of UVA and endogenous photosensitizers, such as porphyrins and flavins (Cadet et al., 1997), which can produce DNA damage. In addition external aggression such as cigarette smoke can induce oxidative stress in human tissues. Cigarette smoke not only contains peroxy radicals but also contains nitric oxide which can facilitate conversion of peroxy radicals into the more highly reactive alkoxy and hydroxy radicals. Exposure to cigarette smoke depletes the intracellular antioxidant thiol glutathione, decreases phagocytic cell chemotaxis, increases epithelial cell permeability and proinflammatory cytokine release, reduces epithelial cell repair processes and can result in cell death (Rahman and MacNee, 1999), (Rusznak et al., 2000).

Feverfew PFE has been shown to directly scavenging a wide range of free radicals, thereby reducing the oxidative damage to skin that can result from the presence of the free radicals. Feverfew PFE had the greatest scavenging activity against ferric radicals, followed by oxygen, hydroxyl, peroxynitrate radicals respectively (Martin et al., 2008). In comparison to the reference antioxidant, Ascorbic acid (Vitamin C), Feverfew PFE has a 5-fold greater scavenging activity for oxygen and hydroxyl radicals than Ascorbic acid, and 3-fold greater scavenging activity for ferric radicals than Ascorbic acid. Feverfew PFE was also 13-fold greater than Ascorbic acid in scavenging the superoxide anion.

Functionally Feverfew PFE was also shown to reduce UV-induced cellular damage in primary human keratinocytes. Exposing normal human keratinocytes to UV increases the production of hydrogen peroxide (H2O2). H2O2 production is represented as mean fluorescent units (MFU). The production of hydrogen peroxide occurs during exposure to UV, so that measurements of hydrogen peroxide immediately after UV exposure can detect significant increases in hydrogen peroxide. A dose of 4.2 kJ/m2 (at 360nm) from a solar simulator increased intracellular hydrogen peroxide by 73%.

Preincubation with Feverfew PFE at concentrations from 3.1 to 100 μg/mL significantly attenuated hydrogen peroxide production in a dose-dependent manner (\*P<0.05 compared with UV exposed vehicle treated control keratinocytes). At concentrations greater than 10 μg/mL the suppression of hydrogen peroxide production was less than in non-irradiated controls indicating that Feverfew PFE reduced the basal level of hydrogen peroxide present in keratinocytes due to metabolism (Tierney, et al., 2005). The activity of Feverfew PFE reducing oxidative stress in keratinocytes was not limited to UV exposure. Exposure to external aggressors such as cigarette smoke was found to increase free radical formation in keratinocytes which was inhibited by Feverfew PFE in a dose dependent manner at concentrations as low as 6 μg/mL. The reduction of oxidative stress in skin cells also helped to preserve the levels of endogenous cellular antioxidants. In cells exposed to cigarette smoke treatment with Feverfew PFE maintained the cellular thiol content at levels similar to

purification processes are available to create feverfew parthenolide-free extract (Feverfew PFE) which does not produce skin irritation and is free of sensitization potential (Kurtz, et

Reactive Oxygen Species are produced in skin following UV irradiation and is a major mediator of oxidative damage to the skin (Pathak and Stratton, 1968). Hydrogen Peroxide (H2O2 ) and peroxyl radicals are produced in skin following UVB irradiation (Stewart et al., 1996) and can induce oxidative damage to DNA and other cellular constituents. Singlet oxygen can be generated from the action of UVA and endogenous photosensitizers, such as porphyrins and flavins (Cadet et al., 1997), which can produce DNA damage. In addition external aggression such as cigarette smoke can induce oxidative stress in human tissues. Cigarette smoke not only contains peroxy radicals but also contains nitric oxide which can facilitate conversion of peroxy radicals into the more highly reactive alkoxy and hydroxy radicals. Exposure to cigarette smoke depletes the intracellular antioxidant thiol glutathione, decreases phagocytic cell chemotaxis, increases epithelial cell permeability and proinflammatory cytokine release, reduces epithelial cell repair processes and can result in cell

Feverfew PFE has been shown to directly scavenging a wide range of free radicals, thereby reducing the oxidative damage to skin that can result from the presence of the free radicals. Feverfew PFE had the greatest scavenging activity against ferric radicals, followed by oxygen, hydroxyl, peroxynitrate radicals respectively (Martin et al., 2008). In comparison to the reference antioxidant, Ascorbic acid (Vitamin C), Feverfew PFE has a 5-fold greater scavenging activity for oxygen and hydroxyl radicals than Ascorbic acid, and 3-fold greater scavenging activity for ferric radicals than Ascorbic acid. Feverfew PFE was also 13-fold

Functionally Feverfew PFE was also shown to reduce UV-induced cellular damage in primary human keratinocytes. Exposing normal human keratinocytes to UV increases the production of hydrogen peroxide (H2O2). H2O2 production is represented as mean fluorescent units (MFU). The production of hydrogen peroxide occurs during exposure to UV, so that measurements of hydrogen peroxide immediately after UV exposure can detect significant increases in hydrogen peroxide. A dose of 4.2 kJ/m2 (at 360nm) from a solar

Preincubation with Feverfew PFE at concentrations from 3.1 to 100 μg/mL significantly attenuated hydrogen peroxide production in a dose-dependent manner (\*P<0.05 compared with UV exposed vehicle treated control keratinocytes). At concentrations greater than 10 μg/mL the suppression of hydrogen peroxide production was less than in non-irradiated controls indicating that Feverfew PFE reduced the basal level of hydrogen peroxide present in keratinocytes due to metabolism (Tierney, et al., 2005). The activity of Feverfew PFE reducing oxidative stress in keratinocytes was not limited to UV exposure. Exposure to external aggressors such as cigarette smoke was found to increase free radical formation in keratinocytes which was inhibited by Feverfew PFE in a dose dependent manner at concentrations as low as 6 μg/mL. The reduction of oxidative stress in skin cells also helped to preserve the levels of endogenous cellular antioxidants. In cells exposed to cigarette smoke treatment with Feverfew PFE maintained the cellular thiol content at levels similar to

**5.1 Feverfew PFE reduces UV and external aggression induced reactive oxygen** 

death (Rahman and MacNee, 1999), (Rusznak et al., 2000).

greater than Ascorbic acid in scavenging the superoxide anion.

simulator increased intracellular hydrogen peroxide by 73%.

al., 2005).

**species formation** 

Fig. 1. Feverfew PFE inhibits Reactive Oxygen Species.

those in the no-smoke exposed control (Martin et al., 2008). Through free radicals scavenging activity and preserving endogenous antioxidant levels, Feverfew PFE may protect skin from oxidative stress that could result in DNA damage.
