Background: Inhibition of starch-hydrolysing enzymes is one of the major methods to reduce the risk of type−2 diabetes mellitus. Nowadays, there are no reports involving oil-rich and oil-low seeds of different botanical origins. The current study intended to extract Phaseolus vulgaris L. and Arachis hypogaea L. including Plukenetia volubilis L. using ethanol and water solvents, and to analyse Fourier-transform infrared (FTIR) fingerprint, total phenolic content, antioxidant and anti-glucosidase activities of the extracts by principal component analysis (PCA) and cluster analysis.

Results: The result showed that the ethanol extracts of P. vulgaris L., A. hypogaea L., and P. volubilis L. showed total phenolic content higher than those of the aqueous extracts. The result also demonstrated that the aqueous and ethanol extracts from P. volubilis L. seed showed the highest antioxidant and anti-glucosidase activities, respectively. In comparison with the efficacy of the aqueous extracts of beans, A. hypogaea L. showed the highest antioxidant activity and anti-glucosidase activity. For the ethanol extract of beans, P. vulgaris L. (red kidney bean) showed the highest antioxidant activity, while P. vulgaris L. (white kidney beans) showed the highest anti-glucosidase activity. Moreover, significantly positive correlations between total phenolic content and anti-glucosidase activity (r = 0.41, P-value = 0.018), and between total phenolic content and FTIR data (r = 0.66, P-value = 0.000) were found.

Conclusions: FTIR of the extracts showed functional groups corresponding with phenolic compounds. Moreover, the PCA and cluster analysis from FTIR data, phenolic content and biological activity could separate solvent types used for extraction.