Biochemical composition and characteristics of salivary FTIR spectra: Correlation analysis

The comparison of the characteristics of FTIR spectra (intensity, area of absorption bands) with the biochemical composition was carried out using the example of human saliva (164 male, average age 47.2 +/- 1.6 years; 135 female, average age 48.7 +/- 1.6 years). The existence of strong correlations of the absorption band at 1637 cm(-1) with the content of alpha-amino acids and chloride ions was shown, which can provide information on changes in the conformational structure and isoelectric point of salivary proteins. A strong correlation was found between the level of lactic acid and the absorption band of thiocyanate ions, which characterizes the activity of saliva peroxidases. It is shown that the nature of the correlations depends on gender. The calculation of all possible combinations of intensities and areas of absorption bands in the FTIR spectra of saliva made it possible to identify potentially informative combinations that were not previously described in the literature. This expands the possibilities for the interpretation of the FTIR spectra of saliva in their biomedical application. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

The study compared the FTIR spectra characteristics of human saliva with their biochemical composition, showing strong correlations between absorption bands and specific components. The correlations were found to be gender-dependent. By identifying potentially informative combinations of absorption bands, the study expanded the interpretation possibilities of FTIR spectra in biomedical applications.