Dual effect of Alternariol on Acetylcholinestrase and Monoamine oxidase Extracted from Different Parts of Rat Brain

Alternariol is a metabolite product of different strains of alternaria tenuis. It's structure has a similarity to cannabinol derivatives .It has a chemical formula 3,4,5 trihydroxy 6‐ methyl dibenzox ‐pyrone. The effect of the alternariol on both acetylcholinestrase (AChE) and monoamineoxidase ( MAO) isozymes which were extracted from whole brain male albino rats and it's different five parts namely : frontal cortex, basal ganglia, cerebellum, pons , medulla oblongata was studied. Kinetic studies were done to determine the type of inhibition of AChE and MAO isozyme, and the enzyme ‐inhibitor dissociation constant (Ki) by alternariol. The results indicated that alternariol inhibited both AChE and MAO isozymes of the cortex and cerebellam more than the extracts of the other parts of the brain .These parts are responsible for perception , motor, sensony, psychic activities, coordination of movements and balance. The inhibition of these isozymes increased with increasing the amount of alternariol added to the assay mixture, i.e., the inhibition was dose dependent and of the competitive type. The values of Ki for alternariol ‐ AChE isozymes varied from 12.0 to 15.0 mmol/L and for alternariol ‐ MAO isozymes varied from 28 to 30 mmol/L. The difference in the degree of inhibition of the extracts of these parts of the brain could be attributed to the slight difference in the structure ( arrangement of the amino acids) of these isozymes ( isozyme phenomenon) and to the distinct gene loci. The inhibition of AChE and MAO by alternariol may save ACh and biogenic amines which are of great importance for the patients suffering from Alzheimer and dementia.