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[Study on the processing of leech by FTIR and 2D-IR correlation spectroscopy]
Bing-Ning Li1, Yan-Wen Wu, Jie Ouyang
1Department of Food Science and Engineering, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China. libin03_2@163.com
Processing traditional Chinese medicine leech alters its protein structure and chemical composition. FTIR and 2D-IR spectroscopy reveal protein inactivation and oxidation of fatty acids and cholesterol post-processing.
Area of Science:
- Analytical Chemistry
- Biochemistry
- Traditional Chinese Medicine (TCM)
Background:
- Traditional Chinese Medicine (TCM) utilizes leeches, but their chemical composition changes during processing.
- Understanding these changes is crucial for TCM efficacy and safety.
Purpose of the Study:
- To analyze the chemical differences in leeches before and after processing.
- To investigate the impact of processing on protein structure and other components.
Main Methods:
- Fourier-transform infrared (FTIR) spectroscopy was employed to analyze chemical structures.
- Two-dimensional correlation infrared (2D-IR) spectroscopy was used to track processing dynamics under heat perturbation.
Main Results:
- Leeches are rich in protein, indicated by amide I and II bands.
- Processing shifted characteristic peaks from 1543 cm⁻¹ (fresh) to 1535 cm⁻¹ (processed).
- Protein structure was damaged, hydrogen bonds broken, leading to inactivation; fatty acids and cholesterol were oxidized.
Conclusions:
- Processing significantly alters the chemical profile of leeches used in TCM.
- Protein denaturation and oxidation of other components occur during processing.
- FTIR and 2D-IR spectroscopy effectively characterize these chemical transformations.
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