Document Type : Research Paper
Authors
1 Department of Biological sciences. Faculty of Science. University of Kurdistan. Sanandaj. Iran
2 Dept of Biological Sciences- Faculty of Science- University of Kurdistan-Sanandaj- Iran
Abstract
Background and objectives: Alzheimer's disease is a progressive neurodegenerative condition that leads to cognitive decline and memory disorders. The primary symptoms include a gradual deterioration of cognitive functions and language abilities. One key factor contributing to Alzheimer's disease is the reduced level of acetylcholine, a crucial neurotransmitter in the brain. This decline is partly attributed to the increased activity of acetylcholinesterase, the enzyme responsible for breaking down acetylcholine. As a result, acetylcholinesterase inhibitors have become a promising treatment option for managing the disease. In recent years, there has been a growing interest in discovering more effective, plant-based drugs with fewer side effects. Frankincense gum (Boswellia thurifera Roxb.) is a significant medicinal plant in Iranian traditional medicine, known for its potential to enhance memory and cognitive function. The solvent used in the extraction process plays a crucial role in determining the quality and potency of the extracted compounds. Therefore, this study aimed to investigate the effect of different extraction solvents on the acetylcholinesterase inhibitory activity of frankincense gum extract.
Methodology: Ethanol, methanol, ether, ethyl acetate, acetone, and hexane were selected as solvents for extracting frankincense gum using the maceration method, followed by concentration with a rotary evaporator. The resulting extracts were then tested for their ability to inhibit acetylcholinesterase activity, as well as for their phenolic and flavonoid content. To evaluate the acetylcholinesterase inhibitory activity, Elman’s method was employed, using a microplate spectrophotometry technique. Various concentrations of the extracts were tested to determine the inhibition percentage and calculate the IC50 values. All measurements were performed in triplicate to ensure accuracy. Extracts exhibiting the most significant inhibitory effects were further analyzed to understand their enzyme inhibition kinetics. The total phenolic content of the extracts was measured using the Folin-Ciocalteu reagent. The absorbance of the reaction products was compared to a standard curve of Gallic acid to quantify the phenolic compounds. The total flavonoid content of the extracts was determined using the aluminum chloride colorimetric method, and the flavonoid content was calculated by comparing the absorbance of the extracts to the standard curve of quercetin solution. This comprehensive analysis allowed for a detailed evaluation of the acetylcholinesterase inhibitory potential and the chemical composition of the frankincense gum extracts, providing valuable insights into their potential as therapeutic agents for Alzheimer's disease.
Results: The ethanol extract of frankincense exhibited the highest inhibitory effect on acetylcholinesterase activity, as indicated by its lowest IC50 value. In contrast, the methanol extract, which had the highest IC50 value, demonstrated the weakest inhibitory effect. The other solvents fell between these two, with increasing IC50 values: hexane < ethyl acetate < ether < acetone. Enzyme inhibition kinetics revealed distinct patterns of inhibition. The acetone extract showed a competitive inhibition pattern, while the hexane extract exhibited a non-competitive inhibition pattern. The ethanolic, ethyl acetate, methanolic, and ether extracts displayed a mixed inhibition pattern. In terms of chemical composition, the ethanol extract contained the highest amount of total phenolic compounds, suggesting a strong correlation between phenolic content and inhibitory activity. However, the total flavonoid content was similar across all extracts, with no significant differences observed between them. These findings highlight the potential of frankincense extracts, particularly the ethanol extract, as promising candidates for further research and development in the treatment of Alzheimer's disease.
Conclusion: The findings of this study demonstrate that the ethanolic extract of frankincense gum exhibits a significant inhibitory effect on acetylcholinesterase enzyme activity. Additionally, this extract contains the highest concentration of total phenols, suggesting that ethanol is an effective solvent for extracting acetylcholinesterase inhibitors, which may possess phenolic properties. Future research aimed at isolating these phenolic compounds could lead to the discovery of potent inhibitors with potential medicinal applications.
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