Isolation and Biological Properties of the Natural Flavonoids Pectolinarin and Pectolinarigenin—A Review

Flavonoids are metabolites widely distributed in plants and commonly present in foods, such as fruits and vegetables. Pectolinarin, which belongs to the flavone subclass, has attracted considerable attention due to its presence in many medicinal plants. It has turned out to be a good biological agent especially due to its antioxidant, anti-inflammatory, antidiabetic, and antitumor activities, evaluated both in vitro and in vivo. Its aglycone, the metabolite pectolinarigenin, is also known for a series of biological properties including anti-inflammatory and antidiabetic effects. In the first overview on the two metabolites here presented, their collection, isolation and the results of their biological evaluation are reported

Centaurea microcarpa Coss. & Dur. (Asteraceae) extracts: New cyanogenic glucoside and other constituents

The phytochemical investigation of both chloroform and ethyl acetate extracts of Centaurea microcarpa Coss. & Dur. led to the isolation of a new cyanogenic glucoside 6'-methacrylate prunasin (3) together with seven known compounds: hydroxy-11β,13-dihydro onopordaldehyde (1), β-sitosterol (2), daucosterol (4), nepetin (5), prunasin (6), astragalin (7) and 7-O-β-D-glucopyranosyl centaureidin (8). Their structures were established by spectral analysis, mainly UV, IR, ESI-MS, 1D & 2D-NMR experiments (COSY, HSQC, HMBC and ROESY).Peer Reviewe

Iridoids and anti-inflammatory properties of <i>n</i>-butanol extract of <i>Linaria tingitana</i> Boiss. & Reut.

<p>The analysis of the <i>n</i>-butanol extract of <i>Linaria tingitana</i> (BELT) by HPLC-DAD–ESI/MS allowed the identification of four iridoids structurally confirmed by NMR and ESI–MS/MS extensive experiments data. The subjection of BELT to the anti-inflammatory activity showed that it exhibited a concentration dependent stabilisation of HRBC membrane, inhibition of protein denaturation and nitric oxide scavenging effect in the <i>in vitro</i> process. These results were confirmed in the <i>in vivo</i> experiments which showed that BELT was found to be most pronounced at 200 mg/kg after carrageenan injection which significantly reduced the swelling in both early and late phases of carrageenan-evoked oedema, as well as a significant reduce at the accumulation of infiltrating cells, inhibition of the myeloperoxidase activity and suppressed the lipid peroxidation. These results were supported by the histological analysis which revealed the reduction of oedema and cells infiltration, this might be influenced by the synergistic action of the above isolated compounds.</p

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