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 αglucosidase 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.