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ASIO Journal of Pharmaceutical & Herbal Medicines Research (ASIO-JPHMR)

Volume 2, Issue 2, 2016, 09-11

Doi no.: 01.2017-79626985; DOI Link: http://doi-ds.org/doilink/01.2017-79626985/

09

DETERMINATION OF TANNINS CONTENT BY TITRIMETRIC METHOD FOR COMPARISON OF DIFFERENT PLANT PRODUCTS

Rashmi Choukarya, Manisha Singh, Jagdish Rathi

NRI Institute of Pharmaceutical Sciences, 1-Sajjan Singh Nagar, Raisen Road, Bhopal (M.P.) (India) -462021

ARTICLE INFO ABSTRACT

Short Communication Article

Corresponding Author:

Manisha Singh

NRI Institute of Pharmaceutical

Sciences, 1-Sajjan Singh Nagar,

Raisen Road, Bhopal (M.P.) (India)

-462021

E-mail: manishamasih85@gmail.com

Tannins represent a wide variety of compounds that can be found in fruits, vegetables, dry extract of red wine, dry extract of grape seeds, tea and dry not edible plants. Tannins are also known as proanthocyanidins possessing useful properties such as antioxidant, anti-apoptosis, anti-aging, anti-carcinogenic, anti-inflammatory as well as anti-atherosclerosis and cardiovascular protection. In the study 5 food products were analysed for their tannins content by titrimetric method, the percentage report of samples were found between 0.0010% to 0.0028% in aqueous extract and between 0.0020 - 0.0081% in methanolic extract. Keywords: Tannins, Plant products, titrimetric analysis, aqueous and methanolic extract

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INTRODUCTION

The reactivity of condensed tannin with molecules of biological significance such as protein, metal ions and polysaccharides has important nutritional and physiological consequences and hence the determination of the content of condensed tannins in plant material is important [1]. Tannin exhibit many biologically significant functions, such as protection against oxidative stress and degenerative disease.

Oxidative stress results in oxidative alteration of biological macromolecules such as lipids, proteins and nucleic acid. It is considered to play a vital role in the pathogenesis of aging and degenerative diseases [2-4]. In order to cope with an excess of free radicals produced upon oxidative stress, human bodies have developed sophisticated mechanism for maintaining redox homeostasis. These protective mechanisms include scavenging or detoxification of reactive oxygen species (ROS), blocking reactive oxygen species production, sequestration of transition metals, as well as enzymatic and non-enzymatic antioxidant defenses produced in body, that is, endogenous [5-6].

Tannins are the most abundant antioxidants in human diets. The main dietary sources of tannins include some common fruits, vegetables and not edible plants [7, 8].

The aim of this study was focused on the determination of tannin in plant products by titrimetric method.

MATERIALS AND METHODS

The study covered five plant products like Peanut, Chickpea, Thyme, Cinnamon, Cumin. Randomized market sampling was taken.

Samples and Chemicals

All samples of plant products were purchased from the local market. Chemicals like Potassium permanganate, sodium oxalate, sulphuric acid, indicator methylene blue and solvent methanol were procured from NRI Institute of Pharmaceutical Sciences, Bhopal, Madhya Pradesh, India and all were of analytical grade.

Tannin Assay

The analysis of tannins content in plant products were performed according to the International Pharmacopoeia [9] and AOAC (Association of analytical communities) method [10] after some modifications. 25ml of infusion were taken into 1liter volummetric flask, and then 25ml of methylene blue solution and 750ml of distilled water were added.0.1N aqueous solution of KMnO4 is used for titration until the blue coloured solution change to green colour. Then few drops of this solution were added at a time until solution becomes green to golden yellow colour. Standard solution of methylene blue was prepared as follows: 6ml of methylene were mixed with 500ml distilled water, 50 ml of concentrated sulphuric acid was added, and the solution were diluted to 1litre and then filtered.

Rashmi Choukarya et al. / ASIO Journal of Pharmaceutical & Herbal Medicines Research (ASIO-JPHMR), 2(2), 2016: 09-11

Doi no.: 01.2017-79626985; DOI Link: http://doi-ds.org/doilink/01.2017-79626985/

The blank tested by titration of a mixture of 25ml methylene blue solution and 750ml distilled water was carried out. All samples were analyzed in triplicates.

Preparation of standard 0.1N KMnO4 solution

3.3g of KMnO4 was dissolved in 1L of distilled water and heated on water bath for 1 hour, after cooling the solution was filtered [8].

Standardization of 0.1N KMnO4 solution

200mg of sodium oxalate was dissolved in 20ml of distilled water 2ml of sulfuric acid was added and heated to 70oc. After heating upto 70oc, titrated with 0.1N potassium permanganate until the pink colour appears [8].

Calculations

The tannins content (T%) in the sample was calculated as follows :[11]

T (%) = (V-V0) × 0.004157 × 250 × 100

g × 25

Where V = Volume of 0.1 N aqueous solution of KMnO4

for the titration of the sample (ml);

Vo = Volume of 0.1 N aqueous solution of KMnO4 for the titration of the blank sample (ml);

0.004517 = tannin equivalent in 1 ml of 0.1 N aqueous solution of KMnO4;

g = mass of the sample taken for the analysis;

250 = Volume of the volumetric flask;

100 = percent (%).

RESULTS AND DISCUSSIONS

The results of tannin content in various plant products are presented in Table 1. Almost all analyzed sample contains tannin in the range of 0.0010% for peanut, 0.0016% for chickpea, 0.0028% for cumin, 0.0011% for thyme and 0.0016% for cinnamon in aqueous extract and 0.0081% for peanut, 0.0020% for chickpea, 0.0026% for cumin, 0.0031% for thyme and 0.0047% for cinnamon in methanolic extract and the graph representation are shown in Figure 1.

Table 1: % Tannin content in both aqueous and methanolic extract

Sl No.

Sample % Tannin content Aqueous Extract Methanolic extract

1. Peanut 0.0010 0.0081 2. Chickpea 0.0016 0.0020 3. Cumin 0.0028 0.0026 4. Thyme 0.0011 0.0031 5. Cinnamon 0.0016 0.0047

Figure 1: % Tannin content in both aqueous and methanolic extract10

Rashmi Choukarya et al. / ASIO Journal of Pharmaceutical & Herbal Medicines Research (ASIO-JPHMR), 2(2), 2016: 09-11

Doi no.: 01.2017-79626985; DOI Link: http://doi-ds.org/doilink/01.2017-79626985/

CONCLUSIONS The present study represents original data for tannin contents in various plant products. The method is so simple to determine the tannin content and can be accepted for routine analysis. It was found that the tannin content in aqueous extract was less than the methanolic extract. The analysis of tannin content was measured by titrimetric method and was found that methanolic extract shows higher percentage of tannin content as compared to aqueous extract.

ACKNOWLEDGEMENT The authors are thankful to NRI Institute of Pharmaceutical Sciences, Bhopal, Madhya Pradesh, India for providing the facility and opportunity to carry out the research work.

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