Total Polyphenols, Flavonoids and Antioxidant Properties of Different Parts of Tamarindus indica Linn of Nigerian Origin

Abstract

Aim: To evaluate the polyphenols, flavonoids and the in vitro antioxidant activity of different parts of Tamarindus indica Linn. Study Design: Methanolic extracts of the leaves, stem bark, root bark, fruit pulp, fruit bark and seeds of Tamarindus indica Linn were analyzed for their total polyphenol contents, flavonoid concentration and antioxidant activities in reference to Gallic acid equivalent (GAE), quercetin equivalent (QE) and Trolox equivalent (TE) respectively. Place and Duration of Study: The study was done at the Department of Biochemistry, Faculty of Science, Ahmadu Bello University, Zaria, Kaduna State, Nigeria between September 2010 and December 2011. Methodology: Total polyphenols and flavonoids concentration of the methanolic extracts were evaluated with the aid of a spectrophotometer using the Folin-ciocalteau’s reagent and aluminum chloride reagent methods, respectively, while the antioxidant activity was evaluated by determining the radical scavenging activities of the extracts on 1, 1-diphenyl- 2-picrylhydrazine (DPPH). Results: The equivalent phenolics and flavonoids contents of the stem, fruit pulp and fruit bark (94±2.1 - 158±2.5 μg GAE /g and 27±1.0 - 39±0.7 μg QE /g respectively) were significantly (P = 0.05) higher than those of the seed, root and leaf (55±0.0 - 66±0.7 μg GAE /g and 21±0.7 - 17±1.0 μg QE /g respectively). The antioxidant activity of the stem, fruit pulp, fruit bark, seed, root and leaf were found to be 168±3.5, 143±3.5, 101±1.4, 83±3.5, 63±3.5 and 40±1.0 μg TE /g respectively. There was a strong positive correlation (r2 = 0.97) between the polyphenols contents and the in vitro antioxidant activity. Conclusions: These results suggest that different parts of T. indica possess high levels of polyphenols with significant antioxidant capacities to warrant further detailed studies on the possible roles of this property in their nutritional and health effects.