Investigation of Tannin content in Diospyros mespiliformis Extract using Various Extraction Solvents

Plants produce many bioactive compounds that are called secondary metabolites, and have a wide variation in chemical diversity, distribution and function [1]. Phytochemistry of plants has revealed the pharmacological effect and their uses in industries [2-4]. Secondary metabolites have long been known as a source of effective medical therapies such as anti-bacterial and anti-cancer as reported [5-7]. The classification is based on the precursor, basic structure and biosynthetic pathway [1]. These compounds are classified into four categories namely: alkaloids, phenols terpenoids, and non-protein amino acids [8]. Phenol group is characterized by the presence of an aromatic ring with one or two hydroxyl groups and consists of thousands of compounds some of which include anthocyanins, flavonoids, glycosides, pigments, lignin melanin, phenolic acids, phenylpropanoid, quinones, saponins, and tannins which are widely distributed in various plant species [9]. Tannins are polyphenolic compounds that have high molecular weight (over 1000 g) and can form a complex with protein. Structurally, tannins can be divided into two classes: condensed tannins and hydrolysable tannins [9,10]. Tannins are distributed in species throughout the plant kingdom and are commonly found in both angiosperms and gymnosperms.Tannins is produced by a chloroplast-derived organelle, the tannosome [11] which are physically located in the vacuoles or surface wax of plants, it contains gum, oil, latex, pigments or resin [12] and function as, excretory materials, minerals, pigments, and storage of reserves. Most common polyphenols are the condensed tannins found in virtually all families of plants, and comprising up to 50% of the dry weight of leaves. Tannins are located in the roots, wood, bark, leaves, and fruit of many plants [13-15]. In plants, tannins play a role of protecting plant from predation and also help in regulating plant growth [16]. Furthermore, it causes the astringency, colour, and flavour in tea [17]. Type of tannins in tropical woods is cathetic while the temperate woods are gallic in nature. There may be a loss in the bioavailability of still other tannins in plants due to birds, pests, and other pathogens. Likewise, the modification of tannins with time plays a significant role in determining harvesting times.