Antioxidant and toxicological evaluation of a Tamarindus indica L. leaf fluid extract

In the scientific community, there is a growing interest in Tamarindus indica L. leaves, both as a valuable nutrient and as a functional food. This paper focuses on exploring its safety and antioxidant properties. A tamarind leaf fluid extract (TFE) wholly characterised was evaluated for its anti-DPPH activity (IC50 = 44.36 μg/mL) and its reducing power activity (IC50 = 60.87 μg/mL). TFE also exhibited a high ferrous ion-chelating capacity, with an estimated binding constant of 1.085 mol L(-1) while its influence over nitric oxide production in human leucocytes was irregular. At low concentrations, TFE stimulated NO output, but it significantly inhibited it when there was an increase in concentration. TFE was also classified as a non-toxic substance in two toxicity tests: the acute oral toxicity test and the oral mucous irritability test. Further toxicological assays are needed, although results so far suggest that TFE might become a functional dietary supplement.

Effect of Tamarindus indica L. leaves' fluid extract on human blood cells

Tamarind leaves are edible; however, their saponin content could be toxic to human blood cells. In this article, the effect of tamarind leaf fluid extract (TFE) on human blood cells was evaluated by using several tests. Results revealed that TFE did not cause significant haemolysis on human red blood cells even at the lowest evaluated concentration (20 mg/mL). Blood protein denaturalisation ratio was consistently lower than in control at TFE concentrations greater than 40 mg/mL. Erythrocyte membrane damage caused by the action of oxidative H2O2 displayed a steady reduction with increasing TFE concentrations. In the reactive oxygen species (ROS) measurement by using flow cytometry assay, leucocyte viability was over 95% at tested concentrations, and a high ROS inhibition was also recorded. Protective behaviour found in TFE should be attributed to its polyphenol content. Thus, tamarind leaves can be regarded as a potential source of interesting phytochemicals.