Protective effect of Gymnema sylvestre leaf extract against uranium toxicity in human peripheral blood mononuclear cells

Abstract

Background: Uranium is a toxic heavy metal, naturally present in soil and water, that causes several health effects due to free radical generation and damage to DNA. Gynmenma sylvestre is a pharmacologically important medicinal plant that has been used in the treatment of diabetes and several other ailments. Accordingly, in this analysis, we intended to examine the protective effect of G. sylvestre leaf extract (GSE) against uranium toxicity. Methods: Aqueous leaf extract of Gymnema sylvestre was prepared and its qualitative and quantitative phytochemical analysis was carried out. The antioxidant potential of the extract was analysed. Human lymphocytes isolated from freshly collected blood samples were treated with uranyl nitrate and GSE independently and in combination. The toxic effects of uranium and the protective effect of the leaf extract have been analyzed by MTT assay, micronucleus and gamma H2AX DNA damage response detection. Results: Phytochemical analysis revealed the presence of major and important phytochemical groups such as alkaloids, flavonoids, saponins, tannins, etc. 15 mu g/mL of GSE significantly reduced toxicity in the 3 different uranium concentrations (0.25, 0.50 & 0.75 mM). Cell viability percentage increased from 90.44 to 94%, 80.40 to 86% and 72.03 to 77.40% in the GSE and uranium co-exposure groups. GSE treatment led to statistically significant reduction in the average number of micronuclei observed per 1000 binucleate cells in all three groups with values 30.66, 40 and 48.33 micronuclei respectively. GSE was successful in reducing the gamma H2AX percentages in the treated cell groups with statistically significant protection with values 22.11 +/- 1.56, 48.43 +/- 0.83 and 51.14 +/- 1.78 respectively. Conclusion: This study is the first to report the in vitro toxic effects of uranium in human peripheral blood mononuclear cells as well as the protective effect of Gymnema sylvestre against uranium induced damages. GSE could alleviate DNA damage in cells treated with uranium in a dose-dependent way. Together these findings emphasize that GSE could be a promising protective agent against uranium induced damages and should be further evaluated for the identification of active principle(s). (c) 2022 The Author(s). Published by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).