Comparative Fingerprint and Extraction Yield of Medicinal Herb Phenolics with Hepatoprotective Potential, as Determined by UV-Vis and FT-MIR Spectroscopy

Abstract

The present study was aimed to compare the polyphenolic composition of six medicinal herbs, from wild flora of Romania. The plants investigated, Cynara scolimus (artichoke), Taraxacum officinalis (dandelion), Chelidonium majus (celandine), Hypericum perforatum (St. John's wort), Silybum marianum (Mary thistle) and Lycopodium clavatum (Wolf 's claw) are known, to have hepatoprotective action. Using in parallel glycerol-water, ethanol-water and methanol, the solvent-dependence of the extract fingerprint and composition in bioactive molecules was studied by UV-Vis and Infrared (FT-MIR) spectrometry. The extraction yields, calculated as an extraction factor (EF) were superior in acidic methanol comparative to glycerin and ethanol, favorising the increase in phenolic acids against flavonoid derivatives . Based on the differences of polarity between the three solvents used, higher EF values were obtained for dandelion, artichoke, celandine and St. John wort, more rich in phenolic acids than flavonoids. Mary thistle and Wolf 's claw had lower concentrations of phenolics, but higher content of lignans and terpenoids. Based on the FT-MIR peaks from 8 regions, for each plant extract, has been determined the fingerprint region between 900 and 1500 cm -1 and identified the specific functional groups. A good, significant correlation was found between the concentration of total phenolics calculated by UV-Vis spectrometry and FTIR methods, after calibration with gallic acid. The value of the MIR signal at 1743 cm -1 may be considered a good indicator of phenolics concentration in such extracts. Combined UV-Vis and FTIR spectroscopy are recommended as rapid and reliable tools to investigate the fingerprint and to predict the composition of medicinal plants or to evaluate the quality and authenticity of different standardized formulas.

Irrigation and Light Access Effects on Coffea arabica L. Leaves by FTIR‑Chemometric Analysis

“…Moreover, the superior layers were also discriminated by the 1075 and 1031 cm -1 bands indicating the presence of carbohydrates, as discussed before. 48,51,54,63,64 The band at 1679 cm -1 is consistent with C=C stretching of lipids, 6,55 suggesting that these compounds may be responsible for the inferior layer discrimination. This agrees with that reported by Delaroza et al, 9 in which the lipid contents were higher for the self-shaded leaves than those exposed to direct sunlight, indicating the efficient lipid protective role of secondary metabolism products in the shade.…”

“…The original spectral plot shows this band overlapped with two other bands at 2918 and 2850 cm -1 referring to C-H symmetric stretching of the CH 3 and CH 2 , respectively, indicating the extraction of lipids/proteins. 30,47,48 A band at 1376 cm -1 can be associated to the ionone ring of carotene or due to the C-H symmetrical bending of the methyl of the aliphatic bonds. 49 Other regions with important discrimination between extracts with and without ethanol were around 1676 and 1092 cm -1 , due to large negative values and around 1697, 1073 and 1027 cm -1 , with large positive loading values (Figure 1b).…”

“…6,9,[50][51][52][53] The bands between 1300 to 1000 cm -1 are assigned to C-O bond of esters, ethers, alcohols, among others. 48,51,54,55 Crude extracts obtained by solvents without ethanol possibly contain lipid compounds, while extracts obtained with solvents containing ethanol extract these compounds as well as other metabolites containing more functional groups. This last group of extracts also contained the most similar spectral fingerprints.…”

“…Bands indicated by loadings between 1100 and 1000 cm -1 are possibly C-O stretches of carbohydrates. 48,51,54,63,64 Depending on the water deficit intensity, changes in carbon partitioning in the leaf and the plant as a whole may occur 65 and modify the leaf's carbohydrate levels. 20,[65][66][67] There are reports in the literature about the decrease in starch content under water stress while other carbohydrates increase, representing the osmotic adjustment strategy [68][69][70] and suggesting that the bands of leaves from non-irrigated plants are the derivative products of carbohydrate.…”

Phytochemical Analysis and Chemical Fingerprinting of Seeds of Abrus Precatorius L.

“…A peak at 3420.96 indicated N-H (amines) stretching. This lies in the range between 3350-3600 cm -1 corresponds to stretching vibrations of OH groups from water, alcohols, phenols, carbohydrates, peroxides as well as from amides 18 . No absorbance between 2220-2260 indicates that no cyanide is present indicating absence of toxic substances 17 .…”