EFFECT OF AQUEOUS EXTRACT OF KING OF BITTERS (Andrographis paniculata Burm. F.) ON KEY ENZYMES LINKED TO NEURODEGENERATION IN RATS

Abstract

Neurodegeneration is a condition that leads to the loss of structure and function of neurons. (Andrographis paniculata [AP]) is a plant herb that is used traditionally in folklore to treat various disease conditions. This study revealed the effect of aqueous extract of King of Bitters (AP) on antioxidant status, cholinergic, monoaminergic and purinergic enzymes in scopolamine-induced neurodegeneration in rats. In vitro study showed that A. paniculata extract had antioxidant potential and was able to scavenge 1, 1-diphenyl-2- picrylhydrazyl (DPPH), Azino-bis-3-Ethylbenzo-Thiazoline-6-Sulfonate (ABTS) and Hydroxyl (OH) radicals in dose dependent manner. AP also inhibited Acetylcholinesterase (AChE) and Butyrylcholinesterase (BChE) activities in vitro in concentration dependent manner. Acute toxicity of the plant was carried out to determine the dose to be used for the in vivo study. Results from the study revealed that the plant is safe at 2000 mg/kg. 50 mg/kg and 500 mg/kg of AP extract were used for the in vivo study. Scopolamine was used to induce neurodegeneration in the rats. Behavioural studies (Water Morris maze and Y-maze) revealed that there was an increase in latency of escape and a decrease in memory index respectively in the hippocampus of rats that received scopolamine. However, treatment with AP extract reversed these effects by improving cognition. AChE, BChE and Monoamine oxidase (MAO) activities were significantly increased in the hippocampus of the rats that were administered scopolamine. However, treatment with the aqueous extract of AP inhibited the activities of these enzymes as well as improved the antioxidative status by increasing total thiol, non-protein thiol levels and decreasing reactive oxygen species production. This study has shown that aqueous extract of A. paniculata possess neuroprotective and antioxidant potential and could be used in the management of neurodegenerative disease such as Alzheimer’s disease.