Sources, Utilization and Biological Activity

**3**

**Chapter 1**

**Abstract**

Hardwood Tannin: Sources,

*Atanu Kumar Das, Md. Nazrul Islam, Md. Omar Faruk,* 

Tannins are found in widely distributed species of plants, and it protects plant from predators and pests. There are three major groups of tannins, that is, hydrolyzable, complex, and proanthocyanidins. Tannins are being used as a significant element for the tanning of animal hides in the leather production industry from the beginning of tannin industry. Then, these have been used for mineral absorption and protein precipitation purposes since the 1960s. Tannins are used for iron gall ink production and wood-based industry as adhesive and anticorrosive, recovering uranium from seawater and removing mercury and methylmercury from solution. In addition, tannins are considered as bioactive compound in nutrition science, and their possible effects on health are to be identified. This chapter outlines the structural and biological properties of hardwood tannins to indicate the positive utilization of them. It also describes the contemporary information on tannins.

*Md. Ashaduzzaman, Rudi Dungani, Enih Rosamah,* 

**Keywords:** tannin, structural properties, biological properties, utilization

Plants are protected from herbivores and diseases due to the accumulation of a wide range of "secondary" compounds, together with alkaloids, terpenes, and phenolics. Phenolic metabolism helps to produce a wide variety of compounds ranging from the familiar anthocyanidins (flower pigments) to lignin (complex phenolics of the plant cell wall). Generally, the chemical and biological criteria of phenolic compounds are called as tannins which are different from other plant secondary phenolics. The word "tannin" originates from the ancient Celtic word for oak [1]. Seguin has introduced the term "tannin" to explain the ability to convert hide or skin into leather by organic material extracted from certain plant tissues in 1796 [1]. Tannin is a chemical component obtained from plant, and it has been used for the benefit of human being from the beginning of its development. To get the idea about its complete nature, a lot of research work is needed till today, and that is why it is considered the "dark continents" of science. Tannin has the ability to make

Tannins are the main polyphenolic secondary metabolites distributed widely in the range of 5–10% of dry plant material in vascular plants. They are found mainly in the bark, stems, seeds, roots, buds, and leaves [3]. Tannins are either galloyl

Utilizations, and Prospects

*Sri Hartati and Alfi Rumidatul*

**1. Tannin and its classification**

proteins and other polymers like pectin [2].
