Medicinal plants of northern Thailand used by traditional doctors to treat mild cognitive impairment in the elderly

Mild Cognitive Impairment (MCI) is the transition stage between normal aging and dementia. Memory impairment, in excess of what is considered normal for age, is the most common symptom of MCI. Some forms of dementia can be treated by increasing the amount of acetylcholine in the synapses of neurons by preventing its breakdown by the enzyme acetylcholinesterase. By inhibiting this enzyme more acetlycholine is available to the brain. The objective of this project is to investigate Thai medicinal plants with potential to slow the progression of MCI to dementia, and treat the memory loss that accompanies this disorder. Interviews were conducting with traditional doctors in Northern Thailand to identify plants with cognitive enhancing and neuroprotective activity. In vitro bioassays measuring total phenolic content, anti-oxidant and acetylcholinesterase activity were performed. One plant was selected for in vivo behavioral and enzymatic testing in normal, female rats. Behavioral models were used to measure spatial and non-spatial memory, and retention. Enzymatic tests of three different portions of the brain, the hippocampus, striatum and cortex were used to determine the level of acetylcholine and enzymes marking free radical oxidation. Many of the selected plants and plant formulas demonstrated anti-oxidant and acetylcholinesterase inhibition activity. My research successfully identified a single plant, which enhanced spatial memory, possessed strong acetylcholinesterase activity and offered protection against free radical oxidation. This research demonstrates the ability of traditional medical systems to provide solutions to modern problems.