Green Coffee Bean Extract in Human Health

Debasis Bagchi, Hiroyoshi Moriyama, Anand Swaroop

• Publisher: CRC Press
• Year: 2016
• eBook ISBN: 9781315353982
• Edition: 1
• Topic: Medicine
• Subtopic: Alternative & Complementary Medicine

The role of green coffee bean (GCB) in human health is of emerging interest to the nutraceutical field, especially given its role in improving metabolic syndrome, including weight management, hypertension, diabetes, and neuroprotection. GCB extract contains a novel antioxidant known as chlorogenic acid (also caffeoylquinic acid), which has been shown to positively affect blood pressure, brain health, diabetes, and weight management. This book provides information on the diverse health benefits of green coffee bean extract, molecular mechanisms and signaling pathways, safety of GCB, dosage, and recommended usage. It focuses on the chemistry, biochemistry, pharmacology, and safety of GCB extract.

GCB extract has brought a remarkable revolution in the nutraceutical marketplace. However, some controversies have been demonstrated recently. This book presents the state-of-the-art research studies from eminent scientists around the world on the potential and diversified health benefits of GCB extracts, with particular emphasis placed on the importance to standardize the appropriate extraction technology, quality control and assurance, and broad spectrum safety studies and human clinical studies to substantiate the regulatory claims and position the product in the marketplace.

1 Green Coffee Bean Extract and Chlorogenic Acids

Chemistry and Novel Antioxidant Benefits

Rajesh K. Kesharwani, Prabhakar Singh, and Raj K. Keservani

CONTENTS

1.1 Introduction

1.2 Antioxidant Potential of Green Coffee Bean Extracts (GCBE)

1.3 Composition of Green Coffee Bean Extracts (GCBE)

1.4 Chlorogenic Acids

1.4.1 Chemistry

1.4.2 Chemistry of Bioavailability

1.4.3 Antioxidant Potential and Biological Activities of Chlorogenic Acid

1.5 Health Benefit Effects of Green Coffee Bean Extract and Chlorogenic Acid

1.5.1 Obesity

1.5.2 Diabetes

1.5.3 Cardiovascular Disorders

1.5.4 Anticancer Effects

1.5.5 Multifocal Electroretinography

1.5.6 Brain Health

1.6 Conclusion

References

ABSTRACT

Coffee is the most widely consumed beverage in the world. Green coffee bean extract (GCBE) is derived from the coffee before it is roasted. It has potential to induce weight loss, stimulate the liver cells to increase fat metabolism, and reduce fat accumulation in the body without causing caloric restriction. The beneficial health effects of green coffee bean extract are attributed to its high anti-oxidant activity detected in chlorogenic, ferulic, caffeic, and n-coumaric acids. Chlorogenic acid (CGA) ((1S,3R,4R,5R)-3-{[(2E)-3-(3,4-dihydroxyphenyl) prop-2-enoyl]oxy}-1,4,5-trihydroxycyclohexanecarboxylic acid), the ester of caffeic acid and (−)-quinic acid, is the most studied bioactive polyphenolic compound of green coffee bean extract. It is derived from cinnamic acid synthesized during lignin biosynthesis, and it has been reported to elicit pleiotropic health-promoting effects due to its antioxidant and anti-inflammatory activities. Antioxidants trap free radicals and protect the body from damage caused by free radical–induced oxidative stress. Epidemiological studies have presented the possibility of chlorogenic acid and green coffee bean extract to be considered as phytomedicine. The objective of this study focused on the chemistry, antioxidant potential status, and various health-promoting effects of chlorogenic acid and green coffee bean extracts.

Keywords: green coffee been extract, chlorogenic acid, antioxidant, obesity, diabetes, bioavailability

List of Abbreviations

CGA chlorogenic acid

GCBE green coffee bean extract

GSH glutathione

SOD superoxide dismutase

1.1 INTRODUCTION

Antioxidants are molecules that inhibit the oxidation of biomolecules. Oxidation is a chemical process that involves the loss of electrons, which leads to an increase of oxidation, resulting in the production of free radicals. The presence of free radicals in the biological system starts a vicious chain reaction of oxidation of biomolecules. Oxidative chain reactions in cells induce the conformation changes in biomolecules, reflecting cellular damage that leads to cell death. Antioxidants mitigate free radical–mediated oxidative damage of biomolecules by directly neutralizing the free radicals or breaking the chain reaction. Antioxidants do this by being oxidized themselves. Antioxidants are often reducing agents such as thiols, ascorbic acid (vitamin C), or polyphenols (Sies 1997).

Plants and their extracts have been used as medicine since ancient times to cure various diseases. Bioactive compounds present in plants and their products have been documented to possess different biological activities that implicate their use as therapeutic agents against several chronic human diseases (Rizvi and Pandey 2009b). Coffee is one of the most popular beverages due to its pleasant flavor and pharmacological properties. Beneficial health effects of GCBE have been attributed to chlorogenic acid (CGA) and other strong antioxidant molecules (Moreira et al. 2005). Green coffee bean extract is derived from the coffee bean before roasting. The two species of coffee plants that have the greatest commercial importance are Coffea arabica and Coffea robusta. These two species differ in chemical composition and antioxidant potential. C. robusta coffee beans exhibited higher antioxidant potential than C. arabica coffee. However, after roasting, there was no significant antioxidant potential differences (Ginz et al. 2000). The effects of GCBE and CGA are multifaceted. An intake of GCBE has been reported to reduce the risk of cardiovascular disease, type 2 diabetes, Alzheimer’s disease, and Parkinson’s disease (Lindsay et al. 2002, Ascherio et al. 2004, Vinson et al. 2009, Salazar-Martinez et al. 2004), and exhibits antibacterial and anti-inflammatory properties (Almeida et al. 2006; Daglia et al. 2007; Bonita et al. 2007). GCBE extract can reduce blood pressure and prevent the onset of high blood pressure (Watanabe et al. 2006; Kozuma et al. 2005). GCBE is proven to be effective in reducing excess weight and tackling obesity (Vinson et al. 2009). Consuming coffee is reported to reduce fatigue and increase the activity of the nervous system.

The beneficial health effects of GCBE have been attributed to both the antioxidant potential enhanced by various polyphenol constituents as well as a major contribution of CGA. Roasting of coffee has been associated with changes in the antioxidant potential depending on the roasting temperature. Here, we will discuss the antioxidant potential, chemistry and bioavailability, and various health benefits due to the antioxidant potential of GCBE and CGA. Oxidative stress in animal cells is often associated with an overproduction of O₂ or H₂O₂. It causes damage to the biological molecules. The accumulation of this damage is the cause of various diseases. The body has several defenses against oxidative stress, including: enzymes, proteins chelating, and transition metals (Perez-Matute et al. 2012). There are other ways to fight against oxidative stress such as biological antioxidants. These are exogenous biological substances that protect biological systems against the deleterious effects of oxidative stress (Perez-Matute et al. 2012).

Coffee is one of the most widely consumed beverages in the world, and therefore the potential health consequences of coffee consumption are of great public interest. Heavy coffee drinking may result in sleep disorders, hypokalemia, and cardiac arrhythmias (Smith 2002; Appel and Myles 2001; Curatolo and Robertson 1983; Cornelis 2012). At the same time, several epidemiologic studies have reported that the risk of Parkinson’s disease, Alzheimer’s disease, and certain types of cancer is reduced in regular coffee consumers (Rosso et al. 2008).

1.2 ANTIOXIDANT POTENTIAL OF GREEN COFFEE BEAN EXTRACTS (GCBE)

There have been various studies over the years on the antioxidant potential of coffee beans and its beverages using different detection methods (Figure 1.1). Scientific evidence has proved that green coffee beverages present high antioxidant properties in vivo and in vitro. Several studies indicate that a high content of polyphenols in coffee leads to higher antioxidant potential, resulting in strong antioxidant action. The concentration of active polyphenols in green beans is influenced by the species and its origin; however, in beverages it depends on the process of brewing. During the roasting process, phenolic compounds in green coffee beans are partially degraded and/or bound to polymer structures, depending on roasting conditions.

FIGURE 1.1 (See color insert.) Green coffee bean fruit.

Antioxidants derived from plants are of interest owing to their observed biological effects such as free radical scavenging ability, inhibition of cellular proliferation, and modulation of various enzymatic activity while also acting as antibiotic, antiallergic, antidiarrheal, anti-ulcer, and anti-inflammatory agents (Rizvi and Pandey 2009b). The antioxidant effects of GCBE are usually attributed to the presence of chlorogenic, ferulic, caffeic, and n-coumaric acids (Yashin et al. 2013). Green coffee has major antioxidant potential as CGA (5–12 g/100 g), which is an ester formed from cinnamic acid and quinic acid and is also known as 5-ocaffeoylquinnic acid (5-CQA) (Ayelign and Sabally 2013). In GCBE, six antioxidant compounds have been identified as caffeoylquinic acids and dicaffeoylquinic acids with radical scavenging potential; however, depending on the roasting process, roasted coffees could produce up to 16 different antioxidant compounds (Van der Werf et al. 2014). It has been reported repeatedly that light roasted coffee displays higher antioxidant activity and total phenolic content of the coffee beans than dark roasted coffee, but less than unroasted (green) bean (Somporn et al. 2011).

During the roasting process, antioxidant molecules such as citric, malic, and CGA were found to decrease as a result of the reduction in antioxidant potential. CGA is observed to degrade during the roasting process (Nebesny and Budryn 2003). Roasting the green coffee beans at 230°C for 12 min reduced the total CGA content by nearly 50%, while roasting it at 250°C for 21 min reduced the CGA to almost trace levels. According to Hecimovic et al. (2011), CGA content was decreased and affected by the degree of roasting in various coffee samples.

A positive but nonlinear relationship was reported for the amount of CGA after roasting (Keservani et al. 2010). Melanoidins formed via the Maillard reaction during roasting of coffee are also known to be increase the antioxidant potential. Melanoidins exhibit antioxidant potential due to the scavenging ability of hydroxyl radicals and the ability to break radical chain reactions through oxygen radicals scavenging. Melanoidins contribute approximately 25% of the total antioxidant activity of coffee. Up to now, only the influence of the roasting condition on the total antioxidant action of coffee has been investigated. The human body relies on antioxidants, which limit the damaging effects of oxidative stress. Dietary antioxidants include phenolic compounds, whereas alkaloid and steroid activity is generally attributed to the hydrogen donating ability of polyphenols, which intercept the free radical chain of oxidation and form a stable end product that does not initiate or propagate oxidation of biomolecules (Sherwin 1978; Singh et al. 2015).

Recent research has presented the possibility of GCBE or CGA to be considered as phytomedicine. The antioxidant potential of GCBE is believed to be more effective than green tea and grape seed (Wild Flavors n.d.). Research conducted in Italy found that green coffee bean extract has greater antioxidant potential than 34 other beverages (Pellegrini et al. 2003). In vivo induction of GCBE against diabetic rats has been reported to increase the antioxidant potential in plasma by increasing the GSH level (Ahmed et al. 2013). The GSH level was found to decrease in the erythrocytes as well as plasma with increasing oxidative stress or decreasing total antioxidant potential in both rats and humans (Rizvi and Pandey 2009a). Regular and decaffeinated coffee intake has been reported to reduce the serum and uric acid concentrations, a product of the catabolism of purines, which increases during oxidative stress, mutagenesis, and probably cancer (Aucamp et al. 1997; Choi and Cyrhan 2007; Kiyohara et al. 1999). Despite inducing the antioxidant molecule level in cell or extracellular fluid, GCBE supplementation also has been reported to modulate the activity of antioxidant enzymes.

The antioxidant potential of caffeine (1,3,7-trimethylxanthine) exhibits levels similar to that of reduced glutathione, which is reported to be significantly higher than ascorbic acid. The antioxidant activity of caffeine was evaluated in a study of oxidative damage in rat liver microsomes. The damage was induced by three reactive oxygen species (ROS) that caused membrane damage in vivo, namely: hydroxyl radical (OH), peroxyl radical (ROO), and singlet oxygen (1O₂). Caffeine was found to be an effective inhibitor of lipid peroxidation at milimolar concentrations against all three reactive species (Devasagayam et al. 1996).

Raw coffee beans are rich in CGA and caffeine, which significantly decrease during the roasting and decaffeination processes (Moon et al. 2009) (Figure 1.2a). The GCBE used in the present study is prepared from decaffeinated and unroasted coffee beans, making it a novel source of CGA and eliminating the possible side effects of caffeine (Smith 2002; Appel and Myles 2001; Curatolo and Robertson 1983). There have been no reports of toxicological studies on GCBE. In a clinical trial, decaffeinated GCBE induced weight loss in overweight volunteers who were administered 400 mg/day for 60 days (Dellalibera et al. 2006). Concurrent with the rise in obesity is the rise in nutraceuticals that may aid weight loss. GCBE is a nutraceutical that has recently received both media and research attention as a weight loss supplement. GCBE is present in green or raw coffee beans. GCBE contains large amounts of CGA, a polyphenol that has antioxidant properties and influences glucose, fat, and brain energy metabolism (Henry-Vitrac et al. 2010; Ho et al. 2012).

Given the high moisture content and fast decomposition of the coffee pulp, one way to preserve it is by...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Dedication
• Table of Contents
• Preface
• Editors
• Contributors
• Chapter 1 Green Coffee Bean Extract and Chlorogenic Acids: Chemistry and Novel Antioxidant Benefits
• Chapter 2 Chlorogenic Acids in Green Coffee Bean Extract Are the Key Ingredients in Food with Health and Function Claims
• Chapter 3 Chlorogenic Acids from Green Coffee Beans: Standard Quality and Extraction Methods
• Chapter 4 Occurrence in Plants and In Vitro, Animal and Human Metabolism of Chlorogenic Acids
• Chapter 5 Mechanism of the Inhibition by Chlorogenic Acids against Postprandial Increase in Blood Glucose Level
• Chapter 6 Beneficial Effects of Green Coffee Bean Extract and Coffee Polyphenols on Metabolic Syndrome
• Chapter 7 Antiobesity Profile of Green Coffee Extract
• Chapter 8 Antihypertension Effects of Green Coffee Bean Extract and Chlorogenic Acids
• Chapter 9 Therapeutic Potential of Green Coffee Bean in Nonalcoholic Fatty Liver Disease
• Chapter 10 Caffeic Acid and Its Biological Effects on Brain Function
• Chapter 11 Coffee and Cognition: Extending Our Understanding beyond Caffeine
• Chapter 12 Nontargeted Metabolomics Reveal Changes in Chlorogenic Acids in Ripening Coffea arabica Green Beans
• Chapter 13 Effect of Green Coffee Bean Extract on Nrf2/ARE Pathway
• Chapter 14 Metabolomics Study of Green Coffee Beans
• Index