Preface

Pomegranate (*Punica granatum L.*) is one of the oldest edible fruits in the Mediterranean and has been used extensively in folk medicine. The popularity of pomegranate has increased especially in the last decade because of its health effects. This book presents a comprehensive overview of pomegranate, its beneficial properties, and potential applications.

The introductory chapter, chapter 1, summarizes previous research on the antioxidant properties and bioactive polyphenolic ingredients in Greek pomegranate varieties. Chapter 2, "Antimicrobial Potential of Pomegranate Extracts", highlights the growing number of publications that have investigated the activity of pomegranate extracts against microbes. Research generally supports folklore claims and has shown that pomegranate extracts possess unusual and potent broad-spectrum activities against Gram-positive and Gram-negative bacteria (planktonic and biofilm), fungi, viruses, and parasites. Possible pathways/mechanisms of antimicrobial activity of pomegranate extracts are discussed and enhancement of such activity using metal ions is considered. The role of pomegranate in cancer treatment and as an adjuvant in therapy has been explored very little because there very few studies have been conducted on humans. However, there are a handful of animal and cellline studies that deem the fruit and its extracts effective in the treatment of cancer. The studies conducted so far, as described in Chapter 3 "Role of Pomegranate in the Management of Cancer", show the potency of pomegranate and its components in the treatment of cancers of the prostate, breast, head and neck, colon, lungs, and skin or as an adjuvant in cancer treatment to minimize unwanted side effects. The various components of pomegranates, because of their antioxidant and antiinflammatory properties, can be applied to various treatment strategies in numerous types of cancer in some way. Pomegranate is still surprising the world with its great therapeutic benefits. Chapter 4, "Vasculoprotective and Neuroprotective Effects of Various Parts of Pomegranate: In Vitro, In Vivo, and Preclinical Studies", in the section on "Pomegranate Health Properties", presents some recent studies on the vasculoprotective and neuroprotective effect of various parts of pomegranate and its main compounds, especially hydrolysable tannins ellagitannins, ellagic acid, and their metabolites. The in vitro and in vivo studies showed that the whole parts of pomegranate as well as its main components had a positive influence on blood glucose, lipid levels, oxidation stress, and neuro/inflammatory biomarkers. As such, they can be used as a future therapeutic agent for several vascular and neurodegenerative disorders such as hypertension, coronary heart disease, and Alzheimer's. Chapter 5 "Could Pomegranate Fight against SARS-CoV-2?", examines the potential properties of pomegranate against SARS-CoV-2 infection. Anti-viral and immune-modulating actions, besides tyrosine kinase and ACE inhibition potentials, all enable pomegranate to fight SARS-CoV-2 infection. In the last few years, the research and development activities on pomegranate fruit have aimed to develop technologies for new pomegranate-derived food products. As described in Chapter 6 "Post-Harvest Management and Value Addition in Pomegranate", in the section on "Post-Harvest Technology of Pomegranate", the pomegranate can be processed into products like minimally processed fresh arils, juice, squash, beverages, molasses, juice concentrates, frozen seeds, jam, jelly, marmalades, grenadine,

wine, seeds in syrup, pomegranate spirits, pomegranate powder, pomegranate rind powder, anardana, confectionery, pomegranate seed oil, and more. These products are not yet popularized on a large scale due to a lack of commercially viable processing technologies. The modified atmosphere packaging offered an additional innovative tool for the optimal use and value addition of lower-grade pomegranate fruits. The minimally processed pomegranate arils and frozen arils packed in punnets and pomegranate juice are the most appealing products to consumers. Pomegranate juice can be used in beverages and jellies, for preparation of pomegranate juice concentrate, as a flavoring and coloring agents, and for dietetic and prophylactic treatment purposes. This new sector of pomegranate industrial processing will allow the use of non-commercial pomegranate fruits with some physical defects and fruit disorders to prepare new products, thus improving pomegranate utilization for human health.

> **Vasiliki Lagouri** Institute of Chemical Biology, National Hellenic Research Foundation, Athens, Greece

Section 1 Introduction

#### **Chapter 1**

## Introductory Chapter: Pomegranate

*Vasiliki Lagouri*

#### **1. Introduction**

#### **1.1 Antioxidant properties and bioactive polyphenolic ingredients in pomegranate varieties**

Pomegranate (*Punica granatum* L.) has been used extensively in folk medicine of many cultures. The popularity of pomegranate has increased tremendously especially in the last decade due to its antimicrobial, anti-viral, anti-cancer, powerful antioxidant and anti-mutagenic effects of the fruit [1–4]. Pomegranate juice has been proposed as a chemopreventive, chemotherapeutic, antiathero-sclerotic and anti-inflammatory agent. Polyphenols, which represent the predominant class of phytochemicals in pomegranate, consist mainly of hydrolyzable tannins such as gallotanins, ellagitannins and ellagic acid, components which have high antioxidant activities [5–8].

These activities are attributed to the pomegranate's high levels of polyphenols content. Polyphenols, represent the predominant class of phytochemicals of pomegranate fruits, mainly consisting of hydrolysable tannins which are mainly located in the fruit peel and mesocarp of pomegranates. Chemical analyses have shown that the pomegranate (juice) contains a significantly high level of hydrolysable tannins, such as gallotannins, ellagitannins and ellagic acid, which exhibited high antioxidant activities [9].

Ellagic acid has been found to exhibit antimutagenic, antiviral, whitening of the skin and antioxidant properties. EA exhibits significant anti-mutagenic, antitoxic, anti-apoptotic, anti-cancer, antibacterial, antiviral, anti-diabetic and anti-inflammatory properties [10–12].

Urolithins are products of metabolism of ellagic acid through the loss of one of the two lactones (lactonase/decarboxylase action) and by successive hydroxyl removal (dehydroxylase activities). In vitro trials have shown anti-inflammatory, anti-cancer, anti-glycemic, antioxidant and antimicrobial effects of urolithins, supporting their potential health benefits attributed to foods rich in pomegranate and ellagitannins [13].

The antioxidant properties and the presence of antioxidant compounds has been reported mostly for pomegranate juice [14–16] however, increasing literature was found reporting the antioxidant activity of pomegranate peels and seeds [16–18].

The extensive knowledge about pomegranate's health attributes and public awareness about nutritional food has increased the demand for the industrial use of pomegranate fruit and its byproducts (peels and seeds). The peels and seeds, which are usually disposed of as waste material in many food-processing industries, could be a rich source of beneficial phytochemicals [19].

Methanol and/or combinations of methanol and other organic solvents have been used for the extraction of polyphenols from pomegranate peels [17, 18]. It is also important to study the use of water as an alternative solvent for the extraction of polyphenols because it is easily accessible, non-toxic, environmentally friendly, and non-hazardous to operator health.

### **2. Previous studies: Results**

A study presented by Lagouri et al., in the 6th International Conference on "Oxidative Stress-Skin Biology and Medicine" 2014 with the title: "Antioxidant properties and phenolic content of Greek pomegranate cultivars" was performed in order to quantify total phenols, flavonoids, hydrolyzable tannins and ellagic acid in the juice, and in the peel and seed extracts of two pomegranate varieties from mainland Greece (Central Macedonia and Thrace) with high pressure liquid chromatography method.

The aims of the study were to prepare aril juices, peel homogenates, peel and seed aqueous and methanolic extracts of two pomegranate cultivars collected from mainland Greece (Central Macedonia: B cultivar and Thrace: C cultivar) and to evaluate:

• their antioxidant properties by using free radical scavenging (DPPH) and ferric reducing antioxidant power (FRAP) assays

**Figure 1.** *DPPH assay.*

**Figure 2.** *FRAP assay.*

*Introductory Chapter: Pomegranate DOI: http://dx.doi.org/10.5772/intechopen.104584*

• their total phenols (TP), total flavonoids (TF), hydrolysable tannins (HT) and ellagic acid (EA) contents by using spectrophotometric and high pressure liquid chromatographic methods [20–24].

In total as shown in **Figures 1**–**3**, the peels from both pomegranate cultivars had higher antioxidant activity and phenol contents compared to juices and seeds. In addition, the B cultivar (Central Macedonia) in its peel homogenates showed higher free radical scavenging activity, total phenol, total flavonoid, hydrolysable tannins and ellagic acid contents than the C cultivar (Thrace). From the results it can be concluded also that different solvents (methanol, water) at temperatures 24 and 40°C used during the extraction process of the peels may affect their antioxidant properties and phenol contents.

In conclusion the results of the study were very promising because pomegranate peels and seeds, which are commonly disposed of as waste in many food processing industries, could be important sources of phytochemicals.

### **Author details**

Vasiliki Lagouri Institute of Chemical Biology, National Hellenic Research Foundation, Athens, Greece

\*Address all correspondence to: vlagouri@eie.gr

© 2022 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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Section 2
