Glycosyl flavonoid profile, <i>in vivo</i> antidiabetic and <i>in vitro</i> antioxidant properties of <i>Linaria reflexa</i> Desf.

<p>Aerial parts of <i>Linaria reflexa</i>, used in North African folk medicine for treating certain skin diseases, were investigated by HPLC–DAD–ESI/MS technique able to identify the glycosyl flavonoids pectolinarin (<b>1</b>), isolinariin A (<b>2</b>), isolinariin B (<b>3</b>), linariin (<b>4</b>), isolinariin D (<b>5</b>) and isolinariin E (<b>6</b>) as the most abundant components in both hydroalcoholic (HAE) and ultrasound-assisted (UAE) extracts profiles. Metabolite <b>5</b>, isolated and fully characterised by extensive nuclear magnetic resonance (NMR) analysis, has been very recently reported from <i>L. japonica</i> together with the compound <b>6</b>. Good antioxidant activities (DPPH radical scavenging, <i>β</i>-carotene bleaching and reducing power assays) were observed for the extracts. The remarkable antidiabetic activity displayed by UAE (300 mg/kg) has yielded the most marked decrease in blood glucose levels of the alloxan diabetic rats (−72.09%), greater than the effects by the drug glybenclamide (−63.29%). This study reports the first correlation of antidiabetic activity of <i>Linaria</i> sp. extracts with their chemical composition.</p