Preface

The natural products derived from medicinal plants have proven to be an abundant source of bioactive compounds, many of which have been the basis for the development of new, leading bioactive molecules in the drug discovery program. With respect to diseases caused by microorganisms, the increasing resistance in many common pathogens to currently used therapeutic agents, such as antibiotics and antiviral agents, has led to the discovery of novel anti-infective chemicals. Currently, information about medicinal plants is contained in somewhat disjointed reports about the helpful qualities and toxic effects of different plant species throughout the world. The aim of this book is to help bring more unity and understanding to this complicated and often contradictory jumble of information.

Some of the most compelling reasons for writing this book include the following:


This contributed volume is organized into four chapters. Chapter 1 is an introduction to the uses of plant extracts and some bioactive compounds from medicinal plants and their potential in the drug discovery program. Chapter 2 discusses the practical experience of Chinese traditional medicine and its preparations. China has a long history in effectively using traditional medicine in different ways to treat diseases that cannot be cured by conventional medicine. Chapters 3 and 4 present research findings on bio-activities of different plants extracts. Faba bean extracts, characterized by a high content of phenolic compounds and condensed tannins, are discussed in Chapter 3, while the antiviral activity of the *Phyllanthus* species is evaluated in Chapter 4.

This book is useful to natural product chemists, pharmacologists, pharmacists, research investigators in industry, physicians, nurses, nurse practitioners, and practitioners of integrative medicine; ethnobotanists, organic gardeners, and farmers; and those interested in herbs and herbal medicine. With the growing interest in this field by professionals and the general public alike, we thought it important to produce a book that encompasses as much information as possible on the importance of extracts obtained from medicinal plants in today's world. We hope that this book helps to meet this need.

I'd like to thank all the authors who have made their expert contributions to the realization of this book, which I hope will stimulate interest for further studies in natural product chemistry.

> **Aman Dekebo** Adama Science and Technology University, Adama, Ethiopia

August 2019

**1**

**Chapter 1**

Extracts

*Aman Dekebo*

**1. Introduction**

systems [5].

Introductory Chapter: Plant

Humans are dependent on plants for basic needs such as food, clothing, and shelter for centuries [1]. Plants have also been used as arrow and dart poisons for hunting, poisons for murder, hallucinogens used for ritualistic purposes, stimulants for endurance, and hunger suppression, as well as inebriants and medicines [1]. Medicinal plants have been a source of wide variety of biologically active compounds for many centuries and used extensively as crude material or as pure compounds for treating various disease conditions. Relatively 1–10% of plants are used by humans out of estimated 250,000–500,000 species of plants on Earth [2]. Plant-based traditional medicine plays a key role in the development and advancement of modern studies by serving as a starting point for the development of novelties in drug discovery [3]. Various modern drugs were extracted from traditional medicinal plants through the use of plant material following the ethno botanical leads from indigenous cures used by traditional medical systems [4]. In developing countries and rural societies, the use of medicinal plants is both a valuable resource and necessity, and furthermore, it provides a real alternative for primary healthcare

Plants were once the primary source of medicines in the world and since then, plants continue to provide humans with new remedies as 50% of all drugs in clinical use in the world are derived from natural products, of which higher plants contribute 25% of the total [5, 6]. The use of plants as medicines predates written human history. Knowledge of plant use was widespread in ancient civilizations. Until the middle of the nineteenth century, plants were the main therapeutic agents used by humans, and even today, their role in medicine is still relevant. It was estimated by the WHO that around 80% of the world population relied on medicinal plants as their primary healthcare source [7] and the demand is increasing in developing countries. For example, traditional medicine (TM) practices have been used for thousands of years by people in Africa, China, India and many other countries [8]. Even in developed countries, plant-based traditional medicines are often termed complementary or alternative medicine (CAM), and their use has increased steadily. For example, in the USA alone, the total estimated that herbal sales for 2005 were \$4.4 billion, a significant increase from \$2.5 billion in 1995 [9].

The plant chemicals used for arrow or dart poisoning purposes are largely the secondary metabolites, which are derived biosynthetically from plant primary metabolites (e.g., carbohydrates, amino acids, and lipids) and are not directly involved in the growth, development, or reproduction of plants. Secondary metabolites can be classified into several groups according to their chemical classes, such as alkaloids, terpenoids, tannins, phenolics, and others [10]. Most of these second-

ary metabolites are used for plants defense against predators.
