FT-IR characteristics, phenolic profiles and inhibitory potential against digestive enzymes of 25 herbal infusions
Prinya Wongsa, Posathon Phatikulrungsun, Sasithon Prathumthong
Abstract
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 ( R 2 ) between antioxidant activity and α-amylase inhibition was 0.46, ( p < 0.05) while that ( R 2 ) 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.