Analysis of flower extract and natural dye solution from Sesbania javanica using Fourier-transform infrared spectroscopy (FTIR) chemometrics, and determination of its antioxidant and anti-glucosidase activities

Abstract

Fourier-transform infrared spectroscopy (FTIR) chemometrics and determination of antioxidant and anti-glucosidase activities of flower extract and natural dye solution from Sesbania javanica were performed. Total phenolic content and total flavonoid content were the highest in ethanolic flower extract, while antioxidant activity (1/EC50 = 0.4935) and α-glucosidase inhibition (1/EC50 = 2.9671) were the highest in dye solution, obtained from mixing white clay filler with aqueous dye extract. The correlations of FTIR data, bioactive compound contents, and biological activities were assessed by partial least squares structural equation modelling. Results showed that a strongly positive relationship was significantly demonstrated between FTIR fingerprints and bioactive compound contents (β = 0.825, t = 17.037, p value < 0.05), and between bioactive compound contents and biological activities (β = 0.563, t = 3.000, p value < 0.05). However, a strongly negative relationship was significantly found between FTIR fingerprints and biological activities (β = -1.204, t = 6.065, p value < 0.05). Moreover, the PCA and cluster analysis from FTIR data led to well grouping in PC plots and phylogenetic trees. Interestingly, the PCA and cluster analysis from FTIR data of plant extracts in powdered form provided better separation in PC plots and phylogenetic trees than in liquid form.