Abstract

Organophosphorous (chlorpyrifos) has been widely used in pest control. It is considered to be a functionally irreversible inhibitor of cholinesterase (ChE), since the time necessary to liberate the enzyme from inhibition may be in excess of time required for the synthesis of new ChE. This study was designed to investigate the effects of total phenolic content, total antioxidant capacity, and free radical scavenging activities in a cell free system present in Thunbergia laurifolia (Linn.) (TL) and further examine their ability against chlorpyrifos-induced ChE dysfunction in vitro (blood and brain of mice) studies. The results showed that TL has the highest phenolic content, which is a significant positive correlation with its antioxidant activity (R² = 0.99). Additionally, the effects of 50 % inhibitory concentration of TL on scavenging free radical activities (IC<inf>50</inf>) for hydroxyl, superoxide, hydrogen peroxide radical and nitric oxide in the cell free system were 1.47±0.02, 2.23±0.08, 1.66±0.09 and 1.00+0.07 mg/mL, respectively. We found TL showed a potential inhibition of chlorpyrifos-induced ChE dysfunction in a concentration dependent manner. These data suggest that TL exhibits anti-oxidant and, at least in part, neuroprotective properties against chlorpyrifos-induced ChE alteration. We strongly believe that these antioxidant constituents are prospective novel nutriceuticals.