Toxicity profiling and antioxidant activity of ethyl acetate extract of leaves of Premna integrifolia L. for its application as protective agent against xenobiotics

Premna integrifoliaL. (Lamiaceae) is widely used in herbal formulation “Dashmoolarishta” which is useful in postnatal care. Ethyl acetate extract obtained from the leaves was evaluated for phenolic content and its antioxidant activity. Acute and subacute toxicity of the extract was studied in mice of both sexes to get an idea about LD₅₀ value and assessed its safety profile before its application as a protective agent against different toxicities induced by xenobiotics. Phenol enriched extract (phenol content is 63.10 ± 1.26 mg/g of gallic acid equivalent and flavonoid content 75.33 ± 0.23 mg/g of rutin equivalent) showed good antioxidant activity. In acute toxicity studies it was observed that single different doses (300−5000 mg/kg b.wt.) of extract did not show any mortality of mice. Thus the LD₅₀ of the extract was determined, and it was higher than 5000 mg/kg. There was no major change in behavioral and general appearance of mice. External morphology of liver, kidneys, lungs, spleen and heart did not show any effect of treatment. In subacute toxicity no statistically significant change in body weight, relative organ weight, food intake and water uptake, hematological, biochemical parameters were reported after comparison with control. Extract did not show significant effect in the level of antioxidant enzymes in the liver of mice of treated groups. No histopathological changes were observed in liver and kidney tissues. Thus, extract did not show any sign of toxic effects, when administered orally to male and female mice at dose level up to 1000 mg/kg. So, it can be utilized as protective agent against toxicity produced by different xenobiotics.

Impact of chronic low dose exposure of monocrotophos in rat brain: Oxidative/ nitrosative stress, neuronal changes and cholinesterase activity

Monocrotophos (MCP) is an organophosphate mainly used as insecticides in agriculture, and veterinary practice to control pests. Exposure to MCP is known to induce significant systemic toxicity in animals and humans. Short term exposure to a high dose of MCP has been reported to cause systemic toxicity, however limited information is available regarding low dose long term exposure in rats. We studied the effects of low dose long term exposure to MCP on oxidative/nitrosative stress, cholinesterase activity and neuronal loss in rat. Male rats were exposed to MCP (0.1 μg or 1 μg/ml) via drinking water for 8 weeks. The pro-oxidant markers such as reactive oxygen species (ROS), lipid peroxidation (MDA), nitrite level and antioxidant markers such as reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) and inhibition of cholinesterase activities were measured to evaluate the effects of MCP on brain along with plasma cholinesterase activity. Neuronal loss was analyzed in cortical region using H&E stained slices. The results suggested that exposure to MC even at the low dose, increased reactive oxygen species, thiobarbituric acid reactive substance levels and decreased glutathione, superoxide dismutase, catalase and cholinesterase activities in brain. No significant effect however, was observed on nitrite levels. Histological analysis revealed that low dose MCP exposure lead to structural changes in the cortical neurons in rats. It can be concluded from the study that low dose long term exposure (lower than No Observed Effect Level) of MCP may lead to the generation of oxidative stress by elevation of pro-oxidants markers and depletion of antioxidant enzymes markers along with inhibition of cholinesterase activity. These changes might thus be considered as the possible mechanism of cortical neuronal loss in these animals.