FT-IR characteristics, phenolic profiles and inhibitory potential against digestive enzymes of 25 herbal infusions

Abstract

The present study aimed to analyse the FT-IR vibrational characteristics and concentration of phenolic compounds in 25 herbal plants using Fourier transform infrared (FT-IR) spectroscopy and Ultra-High Performance Liquid Chromatography (UHPLC) techniques, respectively, and to evaluate its in vitro potential to inhibit enzymes related type 2 diabetes and obesity. The vibrational spectra regions—3400–3200 cm−1—indicated hydroxyl group (O–H) and H-bonded stretching, which is characteristic of polyphenolic compounds. A wide range in phenolic compounds was found among the samples. Caffeic acid is the predominant phenolic compounds in the samples. Total phenolic content ranged from 5.02 mg GAE/g DW to 102.39 mg GAE/g DW. A moderate correlation (R2) between antioxidant activity and α-amylase inhibition was 0.46, (p < 0.05) while that (R2) of p-coumaric acid and α-glucosidase inhibition was 0.54, (p < 0.05). Moreover, the herbal infusions showed potential to inhibit digestive enzymes, the highest being on the infusion based on a cup-serving basis.

Facile Fabrication of Highly Quantum Dot/AuNP-Loaded Tags for a Dual-Modal Colorimetric/Reversed Ratiometric Fluorescence Immunochromatographic Assay

“…As shown in Figure D, there are newly formed CO bonds at around 1645 cm –1 in the spectra of MRQDs–BSA, MRQDs–Ab, and MRQDs–BSA–Ab, suggesting the successful binding between MRQDs and BSA/Ab. At the same time, the C–N bond at around 1540 cm –1 and the O–H bond at around 3400 cm –1 in the spectrum of MRQDs–BSA and MRQDs–Ab infers that BSA or Ab was electrostatically adsorbed onto the MRQDs, instead of being covalently bound. However, the enhanced C–N bond at around 1540 cm –1 and disappearing O–H of MRQDs–BSA–Ab reveal that an amide linkage was formed between BSA and Ab.…”

Utilization of Quince (Cydonia oblonga) Peel and Exploration of Its Metabolite Profiling and Cardioprotective Potential Against Doxorubicin-Induced Cardiotoxicity in Wistar Rats

“…The fingerprint region ranging from 1400 to 900 cm –1 comprises the many characteristic single bands of low intensity that are accredited to precise functional groups like C–H, C–O, C–N, and P–O bonds. In the fingerprint area, the peaks (1580–1615 and 1450–1510 cm –1 ) are ascribed to the CC–C aromatic ring stretching and (670–900 and 950–1225 cm –1 ) to numerous out-of-plane aromatic C–H bending and in-plane bending, respectively …”

“…In the fingerprint area, the peaks (1580−1615 and 1450−1510 cm −1 ) are ascribed to the C�C−C aromatic ring stretching and (670− 900 and 950−1225 cm −1 ) to numerous out-of-plane aromatic C−H bending and in-plane bending, respectively. 32 2.6. HPTLC of the Best Active Extract.…”

Application of the FTIR technique as a non‐invasive tool to discriminate Portuguese olive oils with Protected Designation of Origin

“…Nevertheless, looking at the spectral fingerprint region intervals (3100-2750 cm À 1 and 1850-600 cm À 1 ), the transmittance and the respective transformed derivative values at some specific wavenumbers have slightly different intensities, probably related to differences in the chemical composition of the oils (e. g., phenolic compounds, tocopherols, carotenoids, and sterols), which could be used for olive oils' discrimination. Indeed, peaks in the regions of 3400-3200 cm À 1 are typical of polyphenolic compounds and acids; [36] whereas peaks in the regions of 2850-2750 cm À 1 , 1820-1660 cm À 1 , and 1300-1000 cm À 1 can be related to aldehydes, carbonyls, and esters functional groups, respectively. [37][38] Thus, the FTIR spectra, i. e. transmittance, 1 st and 2 nd derivatives data (Figure 2) were further treated by applying LDA-SA, allowing to establish classification models based on the spectral information related to 10, 8 and 6 selected wavenumbers, respectively (transmittance: 656, 1200, 1331, 1533, 1587, 1720, 2770, 2781, 2789, and 2820 cm À 1 ; 1 st derivative: 1146, 1151, 1259, 1265, 1761, 2826, 3022, and 3084 cm À 1 ; and, 2 nd derivative: 1020, 1047, 1136, 1298, 2841, and 2878 cm À 1 ).…”

“…It should be noticed that the wavenumbers selected by the SA algorithm fall in several specific wavenumber ranges related to acids, aldehydes, esters, hydrocarbons, phenolics and unsaturated or saturated fatty acids (e. g., 3400-3200; 2850-2750, 1820-1660, and 1400-1000 cm À 1 ). [36][37][38] These compounds, individually or combined, are in turn responsible for basic tastes like sweet and bitter, as well as by the trigeminal sensation of pungency, which may explain the successful performance of the FTIR-MLRMs. The accuracy in quantifying the sweet, bitter and pungent intensities was further confirmed by the regression lines (Figure 5) that can be satisfactorily established between predicted (FTIR, repeated K-fold-CV) and experimental (trained panellists) sensory intensities.…”