Biophysical and structural modifications on human erythrocytes induced by ethanolic extracts of Ruta graveolens, Artemisia ludoviciana, and Lippia graveolens: a study by ATR-FTIR spectroscopy

Abstract

By using ATR-FTIR spectroscopy and spectral deconvolution analysis, biophysical and structural modifications induced by ethanolic extracts of Rutta graveolens, Artemisia ludoviciana, and Lippia graveolens (commonly used as medicinal plants) on human erythrocytes were investigated. The extracts were directly applied to the human erythrocytes. Their effects were analysed in relevant spectral regions, including the lipid and phospholipid vibration region (3010–2800 cm⁻¹), the carbonyl (CO) stretching region (1770–1700 cm⁻¹), and the protein regions corresponding to amide I and amide II bands (1700–1600 cm⁻¹ and 1600–1450 cm⁻¹, respectively). The ATR-FTIR characterization of the extracts revealed molecular vibrations associated with the presence of monoterpenes and flavonoids in Ruta graveolens, sesquiterpene lactones and phenolic compounds in Artemisia ludoviciana, as well as phenolic monoterpenes as thymol and carvacrol in Lippia graveolens. Spectral deconvolution analysis revealed shifts and increased intensities in absorption bands, indicating a loss of secondary structures and disruption of the lipid bilayer, as well as conformational rearrangements in proteins. Notably, alterations were observed in the relative proportions of α-helices, β-sheets, and disordered structures. The results obtained through ATR-FTIR spectroscopy and spectral deconvolution analysis provide biophysical evidence that largely elucidates the interactions and effects exerted by the plant extracts on human erythrocytes.