Neuroprotective effect of Brahmi, an ayurvedic drug against oxidative stress induced by methyl mercury toxicity in rat brain mitochondrial-enriched fractions

The present study evaluates the neuroprotective effect of Brahmi against methyl mercury (MeHg) toxicity. The results demonstrated that MeHg-decreased mitochondrial viability in MTT assay and IC50 value was found to be 2.5 mu g/mL. However, Brahmi at 250 mu g/mL concentration effectively prevented mitochondrial damage caused by MeHg in MTT assay. Our results also demonstrated MeHg significantly inhibited catalase enzyme activity, glutathione content and increased the level of thiobarbituric acid reactive substances in mitochondrial-enriched fractions of rat brain. These alterations were prevented by preincubation with Brahmi. In addition, Brahmi reverted glutathione level to normal that was depleted by MeHg, confirming its chelating effect, one of the molecular mechanisms that underlie protection against oxidative damage. Our study also focused on total phenolic and flavonoid contents of Brahmi, and it was found to contain significant amount of phenols and flavonoids. The presence of saponins was detected by HPLC which might be responsible for neuroprotection against MeHg.