Preface

Phenolic compounds represent one of the major secondary metabolites of plants with pharmaceutical, industrial, and therapeutic applications. Flavonoids, quinones, lignans, bioflavonoids, neo-lignans, xanthones, curcuminoids, chalcones, stilbenes, phenylpropanoids, tannins, and coumarins are some examples of the major groups of commonly available phenolic compounds in our daily foods, beverages, and spices. A Scopus database search for phenolics for the period 2005–2015 showed more than 1800 review articles and approximately 50,000 articles having the word "phenolics." This portrays the importance of phenolic compounds in industry, health, and research. **Figure 1** shows the diversity of natural phenolic compounds used for novel drugs, environmental sustainability, and green industry.

From this standpoint, this book presents up-to-date research in natural products and utilization of environmental waste containing phenolic compounds in pharmaceutics for various health disorders (breast, colon, and liver cancer, cataract, degenerative diseases, hyperpigmentation, hyperglycemia, skin disorders, and others), synthesis of nano-silver, green chemistry, click chemistry, and chelating agents for iron overload.

Over four sections, this book addresses several new and controversial issues regarding these interesting and diverse natural molecules with impressive pharmacological and therapeutic effects. Each chapter has been reviewed and revised and the authors have brought current research to make the book more informative, illustrative, and easy to read.

#### **Figure 1.**

*The diversity of natural phenolic compounds used for novel drugs, environmental sustainability, and green industry.*

Section 1 examines the nature and role of phenolic compounds, presenting ongoing and nonconventional research with a focus on marijuana. Section 2 discusses sources, biosynthesis, diversity, metabolic pathways, and the effect of biotic and abiotic stresses on the production of phenolic compounds. Section 3 tackles interesting issues of environmental sustainability, climate change, and green industrial applications of phenolic compounds. Section 4 presents *in vitro*, *in vivo*, preclinical, and clinical biological and therapeutic applications of phenolic compounds in many health disorders including leukemia, COVID-19, aging-associated cardiovascular diseases, and cancer.

This book strikes a balance between developments in scientific research and the premises that researchers must be able to absorb to link scientific advances with clinical practice so that the management of diseases can be based on sound physiological concepts. It is a useful resource for students, clinicians, nutrition specialists, and researchers.
