Phytochemicals of Nutraceutical Importance

Dhan Prakash, Girish Sharma

• Publisher: CAB International
• Year: 2014
• ISBN:
  9781789244311
• Topic: Medicine
• Subtopic: Nutrition, Dietics & Bariatrics

Nutraceuticals are bioactive phytochemicals that protect or promote health and occur at the intersection of food and pharmaceutical industries. This book covers a wide spectrum of human health and diseases, including the role of phytonutrients in the prevention and treatment. It also reviews biological and clinical effect, molecular level approach, quality assurance, bioavailability and metabolism of a number phytochemicals, and their role to combat different diseases.

1 Phytochemicals of Nutraceutical Importance: Do They Defend Against Diseases?

Girish Sharma,¹* Dhan Prakash² and Charu Gupta^2
1Amity Center for Cancer Epidemiology & Cancer Research and Amity Institute of Biotechnology; ²Amity Institute for Herbal Research & Studies, Amity University Uttar Pradesh, Noida, India

1.1 Introduction

The word ‘nutraceuticals’, coined by Dr Stephen de Felice, is derived from the words ‘nutrition’ and ‘pharmaceutical’, and is a food or food product that provides health and medical benefits, including the prevention and treatment of disease (Biesalski, 2001). A potential nutraceutical is one that holds a promise of a particular health or medical benefit; such a potential nutraceutical only becomes an established one after there are sufficient clinical data to demonstrate such a benefit (Pandey et al., 2010). Therefore, a nutraceutical is exhibited to have a physiological benefit or provide protection against chronic disease. Such products may range from isolated nutrients, dietary supplements and specific diets to genetically engineered foods, herbal products, and processed foods such as cereals, soups and beverages. Their bioactive ingredients, the phytochemicals, sustain or promote health and occur at the crossroads of the food and pharmaceutical industries. Such substances may range from isolated nutrients, dietary supplements and specific diets to genetically engineered designer foods, herbal products, processed foods and beverages (Kalra, 2003; Prakash et al., 2004). Chemically the nutraceuticals may be classified as isoprenoid derivatives (terpenoids, carotenoids, saponins, tocotrienols, tocopherols, terpenes), phenolic compounds (cumarins, tannins, lignins, anthocyanins, isoflavones, flavonones, flavonoids), carbohydrate derivatives (ascorbic acid, oligosaccharides, nonstarch polysaccharides), fatty acid and structural lipids (n-3 PUFA, CLA, MUFA, sphingolipids, lecithins), amino acid derivatives (amino acids, allyl-S compounds, capsaicinoids, isothiocyanates, indoles, folate, choline), microbes (probiotics, prebiotics) and minerals (Ca, Zn, Cu, K, Se) (Sharma, 2009). They play a crucial role in maintaining optimal immune response, such that deficient or excessive intakes can have negative impacts on health. Around the world, governing bodies have accepted nutraceuticals as possible nutraceutical therapy in mainstream medical education and health. The healthcare industry demonstrated the shift of a growing population from medical treatment of cancer towards nonprescription nutraceuticals as self-medication in cancer management and prevention. The growing awareness of nutraceutical benefits and shift of healthcare economics in favour of nutraceuticals brought nutraceutical medicine into the spotlight of government health policy on the systematic use of nutraceuticals in prevention and/or control of various chronic diseases (Sharma, 2009).

The recent notion of ‘customized’ or ‘personalized’ medicine and diet is being advocated widely to the field of nutrition that can be used to delay the onset of disease and to sustain optimum human health (Dijsselbloem et al., 2004; Kaput and Rodriguez, 2004). Dietary intake of phytochemicals may promote health benefits, protecting against chronic degenerative disorders, such as cancer, cardiovascular and neurodegenerative diseases. The majority of foods, such as whole grains, beans, fruits, vegetables and herbs, contain phytochemicals (Table 1.1). Among these, fruits and vegetables are significant sources of phytochemicals. These phytochemicals, either alone or in combination, have tremendous therapeutic potential in curing various ailments. Phytochemicals with nutraceutical properties present in food are of enormous significance due to their beneficial effects on human health since they offer protection against numerous diseases or disorders such as cancers, coronary heart disease, diabetes, high blood pressure, inflammation, microbial, viral and parasitic infections, psychotic diseases, spasmodic conditions, ulcers, etc. (Fig. 1.1). The National Cancer Institute has emphasized alternative methods of cancer prevention as public awareness by focusing mainly on lifestyle, eating habits, prevention and control care measures (Sharma, 2009). The major nutraceuticals were reviewed and reported as vitamins and minerals, phytochemicals. The vitamins A, B₆, B₁₂, D, E, folate have been reported as anticancer, immuneprotective and reducing cancer risk in the population at risk of cancer and individuals who used self-medication (Holick, 2008; Milner, 2008; Zhang et al., 2008).

Epidemiological and animal studies suggest that the regular consumption of fruits, vegetables and whole grains reduces the risk of chronic diseases associated with oxidative damage (Kris-Etherton et al., 2002; Scalbert et al., 2005; Cieslik et al., 2006). Carotenoids, tocopherols, ascorbates, lipoic acids and polyphenols are strong natural antioxidants with free radical scavenging activity. Endogenous antioxidant enzymes such as superoxide dismutase (SOD), catalase, glutathione peroxidase, glutathione reductase, minerals such as Se, Mn, Cu, Zn, vitamins A, C and E, carotenoids, limonoids and polyphenols exert synergistic actions in scavenging free radicals. Synthetic antioxidants such as butylated hydroxy anisole (BHA) and butylated hydroxy toluene (BHT) play a useful role in the food and pharmaceutical industries (Kondratyuk and Pezzuto, 2004). The natural antioxidant system is mainly classified into two categories, namely in vitro and in vivo antioxidants.

The majority of the achievement of nutraceuticals is based on self-prescription and own individual experiences. However, it is difficult to realize the phenomenal benefits of nutraceuticals unless controlled clinical trials support the evidence and facts of nutraceutical preventive therapeutic efficacy (Sharma, 2009). This chapter summarizes the evidence for protective and health-beneficial effects of phytochemicals, which have the potential of being incorporated into foods or food supplements as nutraceuticals, or into pharmaceuticals, and to propose implications of the explosion in information for the future development, discovery and use of phytochemicals as nutraceuticals. Although nutraceuticals have significant promise in the promotion of human health and disease prevention, health professionals, nutritionists and regulatory toxicologists should strategically work to plan appropriate regulation to provide the ultimate health and therapeutic benefits to mankind. In this context, longterm clinical studies would be required to scientifically validate the nutraceuticals in various medical conditions. The interaction of nutraceuticals with food and drugs is another area that should be taken into consideration. The effect of different processing methods on the biological availability and effectiveness of nutraceuticals remains to be determined. Similar to drugs, there should also be stringent regulatory controls for nutraceuticals.

Table 1.1. Phytochemicals of nutraceutical importance, their sources and health benefits.

Phytochemicals	Source plant	Health benefits
α-Linolenic acid (ALA)	Flaxseed	Cancer preventive, reduce risk of coronary heart disease
Allicin	Garlic, onion	Antibacterial, anticancer, antifungal, anti-inflammatory, chemopreventive, hepatoprotective, hypolipidaemic, hypotensive and neuroprotective
Anthocyanins	Blackberry, cherry, orange, purple maize, raspberry, red grape	Anti-allergic, anti-inflammatory, antioxidants and pigments
Apigenin	Apple, artichoke, basil, celery, cherry, grape, nuts, parsley	Anti-inflammatory, antioxidant, antispasmodic, chemopreventive, induce apoptosis and inhibits breast and ovarian cancers
Caffeic acid	Artichoke, pear, basil, oregano	Anti-inflammatory, antifatigue and antistress properties
Carotene	Carrots, leafy greens and red, orange and yellow vegetables, pumpkin	Anticarcinogenic, enhances release of immunogenic cytokines IL-1 and TNF-alpha, provide cornea protection against UV light, stimulate DNA repair enzymes
Catechins	Tea	Antioxidant, CNS stimulant and diuretic
Curcumin	Turmeric	Antihypertensive, anti-inflammatory, antioxidant and cancer preventive
Diosgenin	Fenugreek seeds	Hypolipidaemic
Ellagic acid	Cranberry, grape, pecan, pomegranate, raspberry, strawberry, walnut	Anticancer and antioxidant
Ferulic acid	Oats, rice, orange, pineapple, groundnut	Protects against cancer, bone degeneration, menopausal symptoms (hot flushes)
Gallic acid	Tea, mango, strawberry, soy	Cytotoxic and antioxidative activities, antileukemic, antioxidant, anticancer, antineoplastic, anti-inflammatory, antidiabetic
Genistein	Lucerne sprouts, red clover, chickpea, groundnut, soybean	Acts as a phytoestrogen, antioxidant, anticancer agent, heart health and helps people with metabolic syndrome
Lutein	Kale, spinach, red pepper, mango, papaya, kiwi, peach, squash, honeydew melon, plum, avocado	Absorbs damaging blue light, protects against colon cancer
Lycopene	Apricot, papaya, pink guava, tomato, watermelon	Lowers risk of atherosclerosis and prostate cancer
Momorbicin	Karela (bitter gourd)	Antidiabetic
Myristicin	Nutmeg	Hypolipidaemic
Piperine	Pepper	Aeromatic, analgesic, hepatoprotective and stomachic
Quercetin	Red onion, buckwheat, red grape, green tea, apple skin	Strong antioxidant, reduces LDL oxidation, vasodilator and blood thinner
Resveratrol	Blueberry, groundnut, red grape and red wine	Antioxidant, prevents ageing, cancer, diabetes and heart diseases
Rutin	Asparagus, buckwheat and citrus fruits	Strengthens capillary walls
Silymarin	Milk thistle (Silybum marianum)	Protects from UVB-induced carcinogenesis and hepatoprotective
Stigmasterol	Soybean	Anticancer, hypolipidaemic, prevention of osteoporosis
Sulforaphane, glucosinolates	Broccoli sprouts, cabbage, cauliflower, collards, cruciferous vegetables, kale, radish, turnip	Antioxidant, prevents DNA damage, reduces risk of breast and prostate cancers
Ursolic acid	Apple, basil, cranberry, lavender, oregano, rosemary	Anti-inflammatory, antimicrobial and antitumour
Withaferin, withanolides	Withania somnifera	Anticancer and immunomodulator
Zingiberene	Ginger	Antibacterial, antifungal, carminative and in treatment of dizziness

Fig. 1.1. Some important therapeutic properties of phytochemicals.

1.2 Phytochemicals and Their Health Benefits

1.2.1 Polyphenols

Polyphenols are naturally occurring compounds found largely in fruits, vegetables, cereals and beverages. Legumes and chocolate also contribute to the polyphenolic intake. These molecules are secondary metabolites of plants and are generally involved in defence against ultraviolet radiation or aggression by pathogens. Basic researches and epidemiological studies have shown the inverse association between risk of degenerative diseases and intake of a diet rich in polyphenols. The epidemiological studies provide convincing evidence that a diet rich in antioxidants is associated with a lower incidence of degenerative diseases. The major sources of dietary polyphenols are cereals, legumes (barley, maize, nuts, oats, rice, sorghum, wheat, beans and pulses), oilseeds (rapeseed, canola, flaxseed and olive seeds), fruits, vegetables and beverages (fruit juices, tea, coffee, cocoa, beer and wine) (Kaul and Kapoor, 2001; Scalbert et al., 2005; Cieslik et al., 2006; Katalinic et al., 2006; Prakash and Kumar, 2011). Fruits such as apple, grape, pear, cherry and various berries contain up to 200–300 mg polyphenols 100 g^-1 fresh weights. Similarly, a glass of red wine or a cup of coffee or tea contains about 100 mg polyphenols. Their total dietary intake may be about 1 g day^-1, which is about ten times higher than that of vitamin C and 100 times higher than those of vitamin E and carotenoids (Packer and Weber, 2001; Scalbert et al., 2005).

Plant polyphenols are secondary metabolites that are broadly distributed in higher plants. Their unique characteristics are water solubility, intermolecular complexation and antioxidant properties. They are classified as condensed proanthocyanidins, galloyl and hexahydroxydiphenoyl esters and derivatives, or tannins. Polyphenols historically have been considered as antinutrients by nutritionists, because some, e.g. tannins, have adverse effects such as decreasing the activities of digestive enzymes, energy, protein and amino acid availabilities, mineral uptake and having other toxic effects. Detection of the antioxidant activities of many polyphenols has reunited opinion toward the health benefits provided by many of these compounds. The most important dietary phenolics are the phenolic acids (including hydroxybenzoic and hydroxycinnamic acids), polyphenols (hydrolysable and condensed tannins) and flavonoids, the latter being the most studied group. Phenols protect plants from oxidative damage. They have also been studied extensively as antioxidant protectants for human beings and play a beneficial role in reducing the risk of coronary heart disease, diabetes, hypertension and some types of cancer (Gee and Johnson, 2001; Willcox et al., 2004; Arts and Hollman, 2005; Andjelkovic et al., 2006).

The chief constituents of tea polyphenols are flavonols (catechin, epicatechin, catechingallate and epigallocatechin-gallate), flavonols (quercetin, kaempferol and their glycosides), flavones (vitexin, isovitexin) and phenolic acids (gallic acid, chlorogenic acid). They constitute up to 30% of the dry weight of green leaves and from 9 to 10% of the dry weight of black tea leaves. Ferulic acid is associated with dietary fibre linked with hemicellulose of the cell wall by means of ester bonds. Caffeic acid in the form of caffeoyl esters and cumaric acids are common in apples, pears and grapes. Additionally, apples and pears are rich in chlorogenic acid and grapes in gallic acid. Apples contain high levels of quercetin among fruits. Grain-derived products are especially significant in human diet as they have higher concentration of phenolic acids in the outer layers of kernel that constitute the bran. Most of the phenolic acid derivatives are hydrolysable tannins and are usually esterified with glucose. Citrus fruits are major sources of flavonones and hesperidin is found in abundance (120–250 mg l^-1) in orange juice.

Quercetin occurs in its glycosylated form as rutin in fruits and vegetables and onions are a particularly r...

Table of contents

• Cover Page
• Title Page
• Copyright Page
• Contents
• Contributors
• Preface
• Part I: Introduction and Overview
• Part II: Phytochemicals in Disease and Prevention Therapy
• Part III: Potential Alternative Therapeutic Dietary Supplements
• Part IV: Importance and Benefits of Dietary Phytopharmaceuticals
• Part V: Antioxidant Phytonutrients and their Therapeutic Values
• Part VI: Potential Traditional and Novel Food Interventions
• Index
• Footnotes