Raman spectroscopic determination of the qualitative composition of tormentil cinquefoil (Potentilla erecta) and greater burnet (Sanguisorba officinalis)

Introduction. The medicinal plant raw materials (MPRM) of the Rosaceae family are widely used in medicine for the treatment of diseases of various origins. The underground organs of plants of this family contain tannins as the main component and exhibit a similar pharmacological effect. At the same time, the qualitative composition of tannins in various types of MPRM is very similar. The main groups of biologically active substances in the plant substances are currently identified using qualitative test tube reactions, thin-layer chromatography and less often the UV spectrum. Raman spectroscopy is not practically used to analyze in MPRM. Referring Raman spectroscopy to non-destructive methods of analysis is important for plant objects. Crushed and powder raw materials can be analyzed. Objective: to study whether Raman spectroscopy can be used to identify MPRM of one family, morphological group, and chemically similar (using the example of the underground organs of tormentil cinquefoil (Potentilla erecta) and greater burnet (Sanguisorba officinalis). Material and methods. The investigation objects were the rhizomes of tormentil cinquefoil and the rhizomes and roots of greater burnet, which had been harvested in the Sechenov University Botanical Garden, as well as industrial samples of raw materials. Spectroscopic analysis was carried out using a RAMAN module device to the Thermo Nicolet NRX-FT Raman IR-Fourier spectrometer. Results. The Raman spectra of the test powders of MPRM of both objects and the samples of standard substances showed fluctuations of molecules corresponding to the chemical composition. Raman spectroscopy could confirm the presence of gallic acid and glucose, as well as their derivatives (tannin and starch), in the underground organs of the examined objects. The resultant spectra of raw material samples had the similar maxima with those of the standards of polyphenolic structure and polysaccharides. But despite all the similarity of the Raman spectra, they have differences that make it possible to distinguish the objects under study, which can be used to characterize a specific type of raw materials. Conclusion. The conducted studies indicate that Raman spectroscopy allows identification of the chemically similar types, including those as powders. The studied spectra can become one of the additional spectral characteristics of the identity of pharmaceutical substances of plant origin.