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Natural Phytochemical Nrf2 Activators for Chemoprevention

Dr. Hank Liers here considers mechanisms involved in the activation of transcription factor Nrf2. Nrf2 is encoded by the NFE2L2 gene. Nrf2 can induce expression of genes encoding for antioxidant enzymes. Thus, it contributes to regulation of oxidative stress. Dr. Liers’ interest regards use of natural phytochemical Nrf2 activators for improving health. Also, see his post, “New Directions for Preventing Free-Radical Damage”(06.27.19).

INTRODUCTION
Nrf2 SIGNALING, FOODS, AND HEALTH

Dr. Hank Liers, PhD nrf2 activatorsDespite progress in the early detection and treatment of cancer, overall mortality rates for most cancers of epithelial origin have not declined during the past three decades. Consequently, in recent years attention has been directed to cancer prevention.

Carcinogenesis can be viewed as a multistep process in which the genes controlling proliferation, differentiation, and apoptosis are transformed and altered under selective environmental pressures.

Tumor development involves three distinct, yet closely linked, phases: initiation, promotion, and progression. The initiation phase is a rapid and irreversible event that occurs when a normal cell is exposed to a carcinogenic event. Frequently, unrepairable or misrepaired DNA damage happens in the initiation phase.

Promotion and progression processes are relatively longer processes than the initiation stage, and are considered reversible. Using various animal cancer models, scientists found that all three cancer development stages can be intervened by treatment with natural (or synthetic) chemicals.

Epidemiological and population studies also establish a close relationship between incidence of cancer and consumption of certain types of food.

The term “chemoprevention” was first coined in 1976 by Michael Sporn, when he referred to prevention of malignancy development by vitamin A and its synthetic analogs. Since then, chemoprevention has been adopted as one of the major tactics to modulate the process of carcinogenesis. Many research studies have proven this strategy is effective in reducing the incidence of cancer in well-defined high-risk groups.

Chemoprevention is by definition the use of natural (or pharmacologic) agents to inhibit the development of invasive cancer. The chemicals with a cancer preventive activity are referred to as chemopreventive agents. A chemopreventive agent can inhibit carcinogenesis either by blocking the DNA damage at initiation stage or by arresting or reversing the processes at promotion and progression stages. Most of the chemical substances used in cancer chemoprevention studies are natural phytochemicals found in food.

On the basis of the inhibition stages, chemopreventive agents have been classified into two categories, namely blocking agents and suppressing agents. Blocking agents act by preventing carcinogens from reaching the target sites, from undergoing metabolic activation, or from subsequently interacting with crucial cellular macromolecules such as DNA, RNA, and proteins at initiation stages.

Suppressing agents, on the other hand, inhibit the malignant transformation of initiated cells at either the promotion or the progression stage. Some agents may work on all three stages of carcinogenesis, and are hence classified into both categories.

DIETARY PHYTOCHEMICALS ARE NATURE’S CHEMOPREVENTIVE AGENTS

Many different animal models and cancer cell lines have been used to evaluate the chemopreventive values of phytochemicals, and have led to the discovery of new classes of chemopreventive agents. These agents include isothiocyanates (such as sulforaphane) from cruciferous vegetables, polyphenols from green and black tea, curcuminoids (from turmeric root), stilbenes such as resveratrol (from giant knotweed plant), flavonoids such as quercetin, and anthocyanidins (from many fruits and soybeans).

Progress also has been made in understanding the mode of action of newly identified chemopreventive agents. Exposure to the chemopreventive agents produces certain level of reactive oxygen species (ROS) or electrophiles, and causes mild oxidative/electrophilic stresses in cells.

Ultimate Protector+

Such mild oxidative stresses are sufficient to initiate the signaling pathways that, in turn, can activate a variety of cellular events, such as induction of phase II detoxification enzymes and antioxidant enzymes, expression of tumor-suppressor genes, and inhibition of cell proliferation and angiogenesis.

In order to survive under a variety of environmental or intracellular stresses, our cells have developed highly efficient protective mechanisms to protect themselves from oxidative or electrophilic challenges. Proteins that comprise phase II detoxification and antioxidant enzymes provide an enzymatic line of defense against reactive oxygen species. These enzymes include superoxide dismutase (SOD), catalase, glutathione peroxidase, glutathione S-transferase (GST), and glutamate cysteine ligase.

Induction of phase II and antioxidant enzymes are regulated at the DNA/gene level by antioxidant responsive element (ARE). ARE-mediated gene expression plays a central role in the cellular defense against cellular oxidative damage.

Experimental evidence supports the view that induction of ARE-mediated cytoprotective enzymes is a critical and sufficient mechanism to enable protection against carcinogenesis provoked by environmental and endogenous insults.

One of the key ARE-binding transcription factors is Nrf2. Induction of cytoprotective enzymes in response to ROS, electrophiles, and chemopreventive agents is a cellular event that is highly dependent on Nrf2 protein.

Nrf2 BOOSTS CELL DETOXIFICATION AND ANTIOXIDANT ENZYMES

By activating Nrf2 signaling, chemopreventive agents can increase cellular detoxification and antioxidant enzymes, thereby enhancing removal of reactive carcinogens and blocking carcinogenesis. This hypothesis has been tested in many studies.

For example, a study with sulforaphane (an isothiocyanate present abundantly in cruciferous vegetables) has shown that oral administration of this phytochemical could effectively block benzo[a]pyrene-induced forestomach tumors in mice. This protective effect was abrogated in mice that could not produce Nrf2, supporting a critical role of phase II detoxification and antioxidant enzymes in the prevention of carcinogenesis by chemopreventive agents.

Nrf2 is normally bound in the cytoplasm of cells to a protein called KEAP1. However, when an appropriate phytochemical agent attaches to a kinase receptor on the cell wall a phosphate group is released that causes the Nrf2 to be released. The Nrf2 then migrates into the cell nucleus and causes an antioxidant enzyme, such as SOD, to be released. This endogenously produced enzyme then can protect against ROS, electrophiles, and chemopreventive agents.

In practice, it has been found that a combination of multiple polyphenols works significantly better than single ingredients at activating Nrf2. In fact, in one experiment it was found that a combination of five ingredients all known to be Nrf2 activators was 18 times more effective than any single ingredient. Furthermore, it was found that this combination of five ingredients  increased levels of SOD by 30% and catalase by 56% after 120 days.

ULTIMATE PROTECTOR+
A POWERFUL, NATURAL Nrf2 ACTIVATION FORMULA FOR GREATER HEALTH

In view of the above information and the fact that new and more effective ingredients are available, we have updated our exceptional formula designed to maximize activation of Nrf2 in the body. This new product is ULTIMATE PROTECTOR+. It is among the most advanced, natural Nrf2 activator formula on the market today.

We include a broad range of Nrf2 activators in ULTIMATE PROTECTOR+. These activators source from a wide variety of freeze-dried and concentrated fruits, vegetables, and herbs. These include USP-grade non-GMO Vitamin C , SFB® standardized fruit blend (~50% polyphenols, high-ORAC powder: 9,000 µmole TE/g) from Grape, Cranberry, Pomegranate, Blueberry, Apple, Mangosteen, Bilberry, Chokeberry, and Goji Berry), Curcumin(standardized extract with 95% curcuminoids), Trans-Resveratrol(98% from Giant Knotweed), Green Tea Extract(90% polyphenols, 50% EGCG),  and VinCare® Whole Grape Extract (>80% polyphenols, ORAC>19,000 µmole TE/g). In addition the product contains Calcium Malate and Magnesium Malate, that support ATP and enzyme product and Bioperine® (a patented black pepper extract that significantly enhances absorption of all ingredients and is a known Nrf2 activator).

Phytochemicals provided by the array of freeze-dried and concentrated fruits, vegetables, and herbs in the formula include: Polyphenols, Phenolic acids, Proanthocyanidins (OPCs), Anthocyandins, Catechins, Glucosinolates, Zeaxanthin, Lutein, Lycopene, Beta Carotene, Chlorogenic acid, Ellagic acid, Quercetin, Quinic acid, Trans-Resveratrol, Ferulic acid, Punicalagins, Phloridzin, Polysaccharides, Xanthones and more.

In addition to these Nrf2 activators (above), ULTIMATE PROTECTOR+ contains an extremely broad array of plant based antioxidants from the same sources described above, as well as from non-GMO USP grade Vitamin C. All ingredients in this product have been used in chemoprevention protocols, as well as in protocols aimed at preventing free-radical damage in the body.

Ultimate Protector is now available on the HPDI website!

 

Ultimate Protector+Ultimate Protector+ is new and improved

 

REFERENCES

“Resveratrol induces glutathione synthesis by activation of Nrf2 and protects against cigarette smoke-mediated oxidative stress in human lung epithelial cells.”  Am J Physiol Lung Cell Mol Physiol 294: L478–L488, 2008.

“Nrf2 as a master redox switch in turning on the cellular signaling involved in the induction of cytoprotective genes by some chemopreventive phytochemicals.” Planta Med. 2008 Oct; 74(13): 1526–39. Epub 2008 Oct 20.

“Nrf2: a potential molecular target for cancer chemoprevention by natural compounds.” Antioxid Redox Signal. 2006 Jan–Feb; 8(1–2):99–106.

“Cancer chemoprevention by phytochemicals: potential molecular targets, biomarkers and animal models.” Acta Pharmacol Sin. 2007 Sep; 28(9): 1409–21.

“Natural dietary anti-cancer chemopreventive compounds: redox-mediated differential signaling mechanisms in cytoprotection of normal cells versus cytotoxicity in tumor cells.” Acta Pharmacol Sin. 2007 Apr; 28(4): 459–72.

“Anticarcinogenesis by dietary phytochemicals: cytoprotection by Nrf2 in normal cells and cytotoxicity by modulation of transcription factors NF-kappa B and AP-1 in abnormal cancer cells.” Food Chem Toxicol. 2008 Apr; 46(4): 1257–70. Epub 2007 Sep 15.

“Signal transduction events elicited by cancer prevention compounds.” Mutat Res. 2001 Sep 1; 480–481: 231–41.

“Targeting specific cell signaling transduction pathways by dietary and medicinal phytochemicals in cancer chemoprevention.” Toxicology. 2010 Dec 5; 278(2): 229–41. Epub 2009 Oct 20.

“NF-kappa B and Nrf2 as potential chemopreventive targets of some anti-inflammatory and antioxidative phytonutrients with anti-inflammatory and antioxidative activities.” Asia Pac J Clin Nutr. 2008; 17 Suppl 1:269–72.

“Regulation of NF-E2-Related Factor 2 Signaling for Cancer Chemoprevention: Antioxidant Coupled with Antiinflammatory.” Antioxid Redox Signal. 2010 Dec 1; 13(11): 1679–98. Epub 2010 Aug 17.

“Molecular targets of dietary phenethyl isothiocyanate and sulforaphane for cancer chemoprevention.” AAPS J. 2010 Mar; 12(1): 87–97. Epub 2009 Dec 15.

“Dietary chemopreventive compounds and ARE/EpRE signaling.” Free Radic Biol Med. 2004 Jun 15; 36(12): 1505–16.

 “Multiple molecular targets in cancer chemoprevention by curcumin.” AAPS J. 2006 Jul 7; 8(3): E443–9.

ADDITIONAL RESOURCES

Ultimate Protector™

The Amazing Healing Potential of Natural Nrf2 Activators – by Dr. Hank Liers

Preventing Free-Radical Damage Using Ultimate Protector™ – by Dr. Hank Liers

New Directions for Preventing Free-Radical Damage  – by Dr. Hank Liers

Ultimate Protector and the Role of Foundational Supplements for Health – by Fred Liers, PhD

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ULTIMATE PROTECTOR+ INGREDIENTS – APPLE

Dr. Hank Liers, PhD biography about us HPDI integratedhealth formulator founder CEO scientist physicist wild bilberry and wild blueberry Ultimate Protector+ includes apple extract, as well as extracts from 12 different fruits, vegetables, and herbs. Each of these ingredients contain substances considered to be polyphenols, antioxidants, and Nrf2 activators. In this article, I explore the ingredient apple (Malus pumila mill.) extract, which is a component of SFB® – Standardized Fruit Blend from Ethical Naturals, Inc.

apple extract

Ultimate Protector+ Includes Apple

SFB® is a proprietary formula that combines extracts from Grape, Cranberry, Pomegranate, Blueberry, Apple, Mangosteen, Bilberry, Chokeberry, and Goji Berry. It is high in fruit polyphenols, flavonoids, anthocyanins, catechins, proanthocyanins, ellagic acid, xanthines, chlorogenic acid, pterostilbenes, resveratrol, phloridzin, quercetin, zeaxanthin, and quinic acid. With its diverse blend, SFB® offers over 40-50% polyphenols as well as >9,000 ORAC units in a single gram.

Polyphenols, anthocyanins and other plant elements are powerful ingredients associated with a variety of areas of human health, including healthy aging, healthy glucose metabolism, cardiovascular health, and inflammation management.

HEALTH BENEFITS OF APPLE

The Apple extract in Ultimate Protector+ has been extracted with non-GMO food grade ethanol and distilled water. Testing has indicated the product contains over 40% polyphenols. In numerous epidemiological studies, apples have been associated with a decreased risk of chronic diseases such as cardiovascular disease, cancer, and asthma.

When compared to many other commonly consumed fruits in the United States, apples had the second highest level of antioxidant activity. Apples also ranked the second for total concentration of phenolic compounds, and perhaps more importantly, apples had the highest portion of free phenolics when compared to other fruits.

APPLE PHYTOCHEMICALS

Apples contain a large concentration of flavonoids, as well as a variety of other phytochemicals, and the concentration of these phytochemicals may depend on many factors, such as cultivar of the apple, harvest and storage of the apples, and processing of the apples. The concentration of phytochemicals also varies greatly between the apple peels and the apple flesh.

Some of the most well studied antioxidant compounds in apples include quercetin-3-galactoside, quercetin-3-glucoside, quercetin-3-rhamnoside, catechin, epicatechin, procyanidin, cyanidin-3-galactoside, coumaric acid, chlorogenic acid, gallic acid, and phloridzin. Recently researchers have examined the average concentrations of the major phenolic compounds in six cultivars of apples. They found that the average phenolic concentrations among the six cultivars were: quercetin glycosides, 13.2 mg/100 g fruit; vitamin C, 12.8 mg/100 g fruit; procyanidin B, 9.35 mg/100 g fruit; chlorogenic acid, 9.02 mg/100 g fruit; epicatechin, 8.65 mg/100 g fruit; and phloretin glycosides, 5.59 mg/100 g fruit.

The compounds most commonly found in apple peels consist of the procyanidins, catechin, epicatechin, chlorogenic acid, phloridzin, and the quercetin conjugates. In the apple flesh, there is some catechin, procyanidin, epicatechin, and phloridzin, but these compounds are found in much lower concentrations than in the peels. Quercetin conjugates are found exclusively in the peel of the apples. Chlorogenic acid tends to be higher in the flesh than in the peel.

Because the apple peels contain more antioxidant compounds, especially quercetin, apple peels may have higher antioxidant activity and higher bioactivity than the apple flesh. Research showed that apples without the peels had less antioxidant activity than apples with the peels. Apples with the peels were also better able to inhibit cancer cell proliferation when compared to apples without the peels. More recent work has shown that apple peels contain anywhere from two to six times (depending on the variety) more phenolic compounds than in the flesh, and two to three times more flavonoids in the peels when compared to the flesh. The antioxidant activity of these peels was also much greater, ranging from two to six times greater in the peels when compared to the flesh, depending on the variety of the apple. This work is supported a study which found that rats consuming apple peels showed greater inhibition of lipid peroxidation and greater plasma antioxidant capacity when compared to rats fed apple flesh.

Many of these phytochemicals from apples have been widely studied, and many potential health benefits have been attributed to these specific phytochemicals. The procyanidins, epicatechin and catechin, have strong antioxidant activity and have been found to inhibit low density lipoprotein (LDL) oxidation in vitro. In mice, catechin inhibits intestinal tumor formation and delays tumors onset. One  study found that chlorogenic acid has very high alkyl peroxyl radical (ROO•) scavenging activity. Compared to about 18 other antioxidant compounds (including quercetin, gallic acid, α-tocopherol), chlorogenic was second only to rutin. Since ROO• may enhance tumor promotion and carcinogenesis, chlorogenic acid may add to the protective effect of apples against cancer. Chlorogenic acid has been found to inhibit 8-dehydroxy-deoxyguanosine formation in cellular DNA in a rat model following treatment with 4-nitroquinoline-1-oxide.

Quercetin is also a strong antioxidant, and is thought to have potential protective effects against both cancer and heart disease. Briefly, quercetin has been found to down regulate expression of mutant p53 in breast cancer cells, arrest human leukemic T-cells in G1, inhibit tyrosine kinase, and inhibit heat shock proteins. Quercetin has protected Caco-2 cells from lipid peroxidation induced by hydrogen peroxide and Fe2+. In mice liver treated with ethanol, quercetin decreased lipid oxidation and increased glutathione, protecting the liver from oxidative damage. Recently, it has been found that high doses of quercetin inhibit cell proliferation in colon carcinoma cell lines and in mammary adenocarcinoma cell lines, but at low doses quercetin increased cell proliferation (20% in colon cancer cells and 100% in breast cancer cells). However, low doses of quercetin (10 uM) inhibited cell proliferation in Mol-4 Human Leukemia cells and also induced apoptosis. Quercetin inhibited intestinal tumor growth in mice, but not in rats. Low levels of quercetin inhibited platelet aggregation, calcium mobilization, and tyrosine protein phosphorylation in platelets. Modulation of platelet activity may help prevent cardiovascular disease.

SCIENTIFIC STUDIES ON THE ANTIOXIDANT EFFECTS OF APPLE

Below, I provide relevant scientific studies on the antioxidant effects and potential health benefits of apple.

Apple phytochemicals and their health benefits

Jeanelle Boyer1 and Rui Hai Liu1

Abstract

Evidence suggests that a diet high in fruits and vegetables may decrease the risk of chronic diseases, such as cardiovascular disease and cancer, and phytochemicals including phenolics, flavonoids and carotenoids from fruits and vegetables may play a key role in reducing chronic disease risk. Apples are a widely consumed, rich source of phytochemicals, and epidemiological studies have linked the consumption of apples with reduced risk of some cancers, cardiovascular disease, asthma, and diabetes. In the laboratory, apples have been found to have very strong antioxidant activity, inhibit cancer cell proliferation, decrease lipid oxidation, and lower cholesterol. Apples contain a variety of phytochemicals, including quercetin, catechin, phloridzin and chlorogenic acid, all of which are strong antioxidants. The phytochemical composition of apples varies greatly between different varieties of apples, and there are also small changes in phytochemicals during the maturation and ripening of the fruit. Storage has little to no effect on apple phytochemicals, but processing can greatly affect apple phytochemicals. While extensive research exists, a literature review of the health benefits of apples and their phytochemicals has not been compiled to summarize this work. The purpose of this paper is to review the most recent literature regarding the health benefits of apples and their phytochemicals, phytochemical bioavailability and antioxidant behavior, and the effects of variety, ripening, storage and processing on apple phytochemicals..

Cancer chemopreventive potential of apples, apple juice, and apple components.

 Gerhauser C1.

From: https://www.ncbi.nlm.nih.gov/pubmed/18855307

Abstract

Apples ( MALUS sp., Rosaceae) are a rich source of nutrient as well as non-nutrient components and contain high levels of polyphenols and other phytochemicals. Main structural classes of apple constituents include hydroxycinnamic acids, dihydrochalcones, flavonols (quercetin glycosides), catechins and oligomeric procyanidins, as well as triterpenoids in apple peel and anthocyanins in red apples. Several lines of evidence suggest that apples and apple products possess a wide range of biological activities which may contribute to health beneficial effects against cardiovascular disease, asthma and pulmonary dysfunction, diabetes, obesity, and cancer (reviewed by Boyer and Liu, Nutr J 2004). The present review will summarize the current knowledge on potential cancer preventive effects of apples, apple juice and apple extracts (jointly designated as apple products). In brief, apple extracts and components, especially oligomeric procyanidins, have been shown to influence multiple mechanisms relevant for cancer prevention in IN VITRO studies. These include antimutagenic activity, modulation of carcinogen metabolism, antioxidant activity, anti-inflammatory mechanisms, modulation of signal transduction pathways, antiproliferative and apoptosis-inducing activity, as well as novel mechanisms on epigenetic events and innate immunity. Apple products have been shown to prevent skin, mammary and colon carcinogenesis in animal models. Epidemiological observations indicate that regular consumption of one or more apples a day may reduce the risk for lung and colon cancer.

Apple Peel Polyphenols and Their Beneficial Actions on Oxidative Stress and Inflammation

. 2013; 8(1): e53725.
Marie Claude Denis, Alexandra Furtos, Stéphanie Dudonné, Alain Montoudis, Carole Garofalo, Yves Desjardins, Edgard Delvin, and Emile Levy
From: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3553108/#

Abstract

Since gastrointestinal mucosa is constantly exposed to reactive oxygen species from various sources, the presence of antioxidants may contribute to the body’s natural defenses against inflammatory diseases.

Hypothesis

To define the polyphenols extracted from dried apple peels (DAPP) and determine their antioxidant and anti-inflammatory potential in the intestine. Caco-2/15 cells were used to study the role of DAPP preventive actions against oxidative stress (OxS) and inflammation induced by iron-ascorbate (Fe/Asc) and lipopolysaccharide (LPS), respectively.

Results

The combination of HPLC with fluorescence detection, HPLC-ESI-MS TOF and UPLC-ESI-MS/MS QQQ allowed us to characterize the phenolic compounds present in the DAPP (phenolic acids, flavonol glycosides, flavan-3-ols, procyanidins). The addition of Fe/Asc to Caco-2/15 cells induced OxS as demonstrated by the rise in malondialdehyde, depletion of n-3 polyunsaturated fatty acids, and alterations in the activity of endogenous antioxidants (SOD, GPx, G-Red). However, preincubation with DAPP prevented Fe/Asc-mediated lipid peroxidation and counteracted LPS-mediated inflammation as evidenced by the down-regulation of cytokines (TNF-α and IL-6), and prostaglandin E2. The mechanisms of action triggered by DAPP induced also a down-regulation of cyclooxygenase-2 and nuclear factor-κB, respectively. These actions were accompanied by the induction of Nrf2 (orchestrating cellular antioxidant defenses and maintaining redox homeostasis), and PGC-1α (the “master controller” of mitochondrial biogenesis).

Conclusion

Our findings provide evidence of the capacity of DAPP to reduce OxS and inflammation, two pivotal processes involved in inflammatory bowel diseases.

APPLE SUMMARY

Apple is an important fruit full of polyphenols, anthocyanins, antioxidants, and Nrf2 activators that help to make Ultimate Protector+ such an outstanding nutritional supplement.