Phenolic constituents of Lamium album: Focus on isoscutellarein derivatives

Abstract

Lamium album L. is an edible plant which is consumed raw or cooked, in particular in the Mediterranean and surrounding areas. It is also consumed as tea infusions and as a main component of food supplements, because of its pharmacological effects. Despite being consumed by humans for centuries, the chemical composition of L. album L. is far from being understood. In this study, a purified ethanolic extract (PEEL) was prepared and further analyzed by high performance liquid chromatography and electrospray mass spectrometry. Overall, verbascoside accounted for approximately half of the phenolic content of the extract, but this also contained other bioactive phenolic compounds herein detected for the first time in the genus, namely isoscutellarein derivatives. The latter included isoscutellarein-7-O-allosyl(1 →2)glucoside, its O-methyl derivative, three acetyl derivatives of isoscutellarein-Oallosyl glucoside and one acetylated form of O-methylisoscutellarein-7-O-allosyl(1 →2)glucoside. From those, the main isoscutellarein derivative was assigned to isoscutellarein-7-O-(6-O-acetyl-β-allosyl)(1→2)-β-glucoside, as confirmed by NMR. Altogether, isoscutellarein derivatives accounted for almost 30% of PEEL phenolics. Since verbascoside and isoscutellarein derivatives are main components of L. album L. ethanolic extract, their possible association to the health benefits of the plant is discussed.

Protective effects of phenolic constituents from Cytisus multiflorus, Lamium album L. and Thymus citriodorus on liver cells

“…Plant extracts C. multiflorus (flowers), L. album and T. citriodorus (aerial parts of both plants) were purchased from Ervital (Castro de Aire, Portugal) and the ethanolic purified extracts of the three plants were obtained and previously characterized regarding their phenolic components (Pereira et al, 2010(Pereira et al, , 2012a(Pereira et al, , 2012b. The content of the main phenolics is summarized in Table 1 (in terms of aglycones and/or their derivatives) due to their relevance for the understanding of the present study.…”

“…The final DMSO concentration was lower than 0.5% and did not affect the cell viability or ROS production (data not shown). Based on the phenolic composition of each target purified ethanolic extract (Pereira et al, 2010(Pereira et al, , 2012a(Pereira et al, , 2012b, three mixtures of phenolic standards were also prepared taking into account the amount of the individual PPCs determined in 50 lg/mL of each extract. In this sense, luteolin, apigenin, quercetin and chrysin were used with final individual concentrations of 1.2, 1.0, 0.7, 3.6 lg/mL, respectively, for the C. multiflorus mixture.…”

“…chrysin-7-O-b-D-glucopyranoside), also containing other flavones and flavonol hexoside derivatives (Pereira, Silva, Domingues, & Cardoso, 2012a). L. album extracts mainly include the phenylpropanoid glycosides verbascoside and isoverbascoside, and some phenolic acids and flavonoids (Paduch et al, 2007;Pereira, Domingues, Silva, & Cardoso, 2012b), while phenolic extracts of T. citriodorus are rich in O-glycosidic derivatives of luteolin and apigenin, as well as in rosmarinic acid (Pereira, Domingues, & Cardoso, 2010).…”

Chemical Profiling and Assessment of Antineurodegenerative and Antioxidant Properties of Veronica teucrium L. and Veronica jacquinii Baumg.

“…The ion at m / z 285 corresponding to the aglycone together with the characteristic UV spectra with maxima at 278, 306, and 326 nm were in agreement with those described for isoscutellarein, a flavone found in the same genus . Based on the previous NMR identification in Veronica species by Albach et al ., and the fragmentation profile similar to that described by Pereira et al ., the compound was identified as isoscutellarein 7‐ O ‐(6‴‐ O ‐acetyl)‐ β ‐allosyl‐(1‴→2‴)‐ β ‐glucoside. Peak 13 in V. jacquinii , with the same molecular ion and similar MS 2 fragmentation as peak 14, was assigned as an isomer of this latter.…”

On-line screening and identification of antioxidant phenolic compounds of Saccocalyx satureioides Coss. et Dur

“…Both ABTS and DPPH tests revealed that caffeic acid, quercetin and isoscutellarein derivatives which were present in higher concentrations in the chromatographic profiles of the extracts were also the most potent antioxidant compounds isolated from this species. All these compounds have been described to exert a wide range of beneficial activities such as the ability to reduce inflammation, to protect against cardiovascular deseases, antioxidant, neuroprotective, againt type 2 diabetes, obesity and anticancer (Pereira et al, 2012;Nabavi et al, 2015).…”