In Vitro Evaluation of Antidiabetic and Anti-Inflammatory Activities of Polyphenolic-Rich Extracts from Anchusa officinalis and Melilotus officinalis

This study was focused on the phytochemical composition and biological activities of Anchusa officinalis and Melilotus officinalis polyphenolic-rich extracts obtained by nanofiltration. The high-performance liquid chromatography-mass spectrometry analysis showed that chlorogenic acid and rosmarinic acid were the main phenolic acids in both extracts. The main flavonoid compound from A. officinalis extracts is luteolin, whereas rutin and isoquercitrin are the main flavonoids in M. officinalis. M. officinalis polyphenolic-rich extract had the highest alpha-amylase (from hog pancreas) inhibitory activity (IC50 = 1.30 +/- 0.06 mu g/mL) and alpha-glucosidase (from Saccharomyces cerevisiae) inhibitory activity (IC50 = 92.18 +/- 1.92 mu g/mL). However, both extracts presented a significant alpha-glucosidase inhibitory activity. Furthermore, the hyaluronidase inhibition of polyphenolic-rich extracts also proved to be stronger (IC50 = 11.8 +/- 0.1 mu g/mL for M. officinalis and 36.5 +/- 0.2 mu g/mL for A. officinalis), but there was moderate or low lipoxygenase inhibition. The studies on the fibroblast cell line demonstrated that both A. officinalis and M. officinalis polyphenolic-rich extracts possess the cytotoxic effect at a concentration higher than 500 mu g/mL. The experimental data suggest that both extracts are promising candidates for the development of natural antidiabetic and anti-inflammatory food supplements.