Exploring the formation of heterodimers of barley hydroxycinnamoylagmatines by oxidative enzymes.

Dimers of hydroxycinnamoylagmatines are phenolic compounds found in barley and beer. Although they are bioactive and sensory-active compounds, systematic reports on their structure-property relationships are missing. This is partly due to lack of protocols to obtain a diverse set of hydroxycinnamoylagmatine homo- and heterodimers. To better understand dimer formation in complex systems, combinations of the monomers coumaroylagmatine (CouAgm), feruloylagmatine (FerAgm), and sinapoylagmatine (SinAgm) were incubated with horseradish peroxidase. For all combinations, the main oxidative coupling products were homodimers. Additionally, minor amounts of heterodimers were formed, except for the combination of FerAgm and CouAgm. Oxidative coupling was also performed with laccases from Agaricus bisporus and Trametes versicolor, resulting in formation of the same coupling products and no formation of CouAgm-FerAgm heterodimers. Our protocol for oxidative coupling combinations of hydroxycinnamoylagmatines yielded a structurally diverse set of coupling products, facilitating production of dimers for future research on their structure-property relationships.

Undescribed Lignanamide and Flavone C-Glucoside Isolated from the Aerial Parts of Piper Samentosum with NO Production Inhibitory Activity in LPS Activated RAW 264.7†Cells.

In this study, two undescribed compounds (1 and 2), together with eight known compounds (3-10) were isolated from the aerial parts of Piper samentosum by various chromatography methods. Their chemical structures were determined to be 7'''-oxolyciumamide N (1), vitexin 2''-O-ß-D-(6'''-feruloyl)-glucopyranoside (2), 1,2-dihydro-6,8-dimethoxy-7-hydroxy-1-(3,4-dihydroxyphenyl)-N1,N2-bis-[2-(-hydroxyphenyl)ethyl]-2,3-napthalene dicarboamide (3), vitexin 6''-O-ß-D-glucopyranoside (4), vitexin 2''-O-α-L-rhamnopyranoside (5), methyl 2-hydroxybenzoate-2-O-ß-D-apiofuranosyl-(1→2)-O-ß-D-glucopyranoside (6), ficuside G (7), methyl 2-O-ß-D-glucopyranosylbenzoate (8), methyl 2,5-dihydroxybenzoate-5-O-ß-D-glucopyranoside (9), and 3,7-dimethyloct-1-ene-3,6,7-triol 6-O-ß-D-glucopyranoside (10) by spectroscopic data analysis including HR-ESI-MS, 1D-, and 2D-NMR spectra. Compounds 1-5 inhibited nitric oxide production in LPS-stimulated RAW264.7 macrophages with the IC50 values of 27.62, 74.03, 38.54, 70.39, and 44.95 µM, respectively. The NMR data of 9 were firstly reported herein.

Inhibitory activity of lignanamides isolated from hemp seed hulls(Cannabis sativa L.) against soluble epoxide hydrolase.

Soluble epoxide hydrolase (sEH) is a therapeutic target for inflammation. In the present study, we isolated one new (1) and four known (2-5) compounds from the ethyl acetate fraction of hemp seed hulls. Their structures were elucidated as lignanamides via nuclear magnetic resonance and mass spectral analyses. All five compounds inhibited sEH activity, with half-maximal inhibitory concentrations of 2.7 ± 0.3 to 18.3 ± 1.0 µM. These lignanamides showed a competitive mechanism of inhibition via binding to sEH, with ki values below 10 µmol. Molecular simulations revealed that compounds 1-5 fit stably into the active site of sEH, and the key amino acid residues participating in their bonds were identified. It was confirmed that the potential inhibitors 4 and 5 continuously maintained a distance of 3.5 Å from one (Tyr383) and four amino (Asp335, Tyr383, Asn472, tyr516) residues, respectively. These findings provide a framework for the development of naturally derived sEH inhibitors.

Biomimetic Enzymatic Oxidative Coupling of Barley Phenolamides: Hydroxycinnamoylagmatines.

Oxidative coupling of hydroxycinnamoylagmatines in barley (Hordeum vulgare) and related Hordeum species is part of the plant defense mechanism. Three linkage types have been reported for hydroxycinnamoylagmatine dimers, but knowledge on oxidative coupling reactions underlying their formation is limited. In this study, the monomers coumaroylagmatine, feruloylagmatine, and sinapoylagmatine were each incubated with horseradish peroxidase. Their coupling reactivity was in line with the order of peak potentials measured: sinapoylagmatine (245 mV) > feruloylagmatine (341 mV) > coumaroylagmatine (506 mV). Structure elucidation of fourteen in vitro coupling products by NMR and MS revealed that the three main linkage types were identical to those naturally present in Hordeum species, namely, 4-O-7'/3-8', 2-7'/8-8', and 8-8'/9-N-7'. Furthermore, we identified two linkage types that were not previously reported for hydroxycinnamoylagmatine dimers, namely, 8-8' and 4-O-8'. We conclude that oxidative coupling by horseradish peroxidase can be used for biomimetic formation of natural antifungal hydroxycinnamoylagmatine dimers from barley.

Molecular docking study of lignanamides from Cannabis sativa against P-glycoprotein.

P-glycoprotein (P-gp), which was first identified in cancer cells, is an ATP-dependent efflux transporter that expels a wide variety of cytotoxic compounds out of cells. This transporter can decrease the bioavailability of therapeutic drugs by preventing their sufficient intracellular accumulation. Over expression of P-gp in cancer cells lead to multidrug resistance (MDR) phenotype that is one of the main reasons for the failure of chemotherapy. Hence, P-gp inhibition is a favorable method to reverse MDR. In this study, the lignanamides from Cannabis sativa were docked against P-gp to recognize potential binding affinities of these phytochemicals. Tariquidar and zosuquidar, two well-known P-gp inhibitors, were selected as the control ligands. It was observed that cannabisin M and cannabisin N exhibited higher binding affinities (- 10.2 kcal/mol) to drug-binding pocket of P-gp when compared with tariquidar and zosuquidar that showed binding affinities of - 10.1 and - 9.6 kcal/mol, respectively. Based on these findings, cannabisin M and cannabisin N could be good drug candidates against P-gp.

Cytotoxic constituents from Isotrema tadungense.

In our search for cytotoxic constituents from Vietnamese plants, the methanolic extract of Isotrema tadungense was found to exhibit significant cytotoxic effect. Subsequent phytochemical investigation of ethyl acetate fractions of this plant led to isolation of 11 compounds including one new arylbenzofuran rhamnoside namely aristolochiaside (1), two aristololactams (2 and 3), three lignanamides (4-6) and five phenolic amides (7-11). Their structures were elucidated by 1 D and 2 D NMR and HR-QTOF-MS experiments. Among the isolated compounds, aristolochiaside (1), aristolactam AIIIa (2) and N-trans-sinapoyltyramine (10) exhibited strong and selective cytotoxicity on the HeLa human cancer cell line with IC50 values of 7.59 ± 1.03, 8.51 ± 1.73 and 9.77 ± 1.25 µM, respectively.[Formula: see text].

Three new lignanamides from the root of Lycium chinense with anti-inflammatory activity.

Three new lignanamides, that is, a new lignanamide (1), and a pair of enantiomers (2a and 2b) were isolated from the EtOAc-soluble fraction of an EtOH extract of the root of Lycium chinense. The structures of these new compounds, including their absolute configuration, were established on the basis of HR-ESI-MS, NMR spectroscopic data and quantum chemical ECD calculations. Compound 2a showed significant anti-inflammatory activity in LPS-induced RAW 264.7 macrophages with the IC50 value of 10.77 ± 2.14 µM, comparing to that of positive control quercetin (17.21 ± 0.50 µM).

Anti-neuroinflammatory effects of grossamide from hemp seed via suppression of TLR-4-mediated NF-κB signaling pathways in lipopolysaccharide-stimulated BV2 microglia cells.

Grossamide, a representative lignanamide in hemp seed, has been reported to possess potential anti-inflammatory effects. However, the potential anti-neuroinflammatory effects and underlying mechanisms of action of grossamide are still unclear. Therefore, the present study investigated the possible effects and underlying mechanisms of grossamide against lipopolysaccharide (LPS)-induced inflammatory response in BV2 microglia cells. BV2 microglia cells were pre-treated with various concentrations of grossamide before being stimulated with LPS to induce inflammation. The levels of pro-inflammatory cytokines were determined using the enzyme-linked immunoassay (ELISA) and mRNA expression levels were measured by real-time PCR. The translocation of nuclear factor-kappa B (NF-κB) and contribution of TLR4-mediated NF-κB activation on inflammatory effects were evaluated by immunostaining and Western blot analysis. This study demonstrated that grossamide significantly inhibited the secretion of pro-inflammatory mediators such as interleukin 6 (IL-6) and tumor necrosis factor α (TNF-α), and decreased the level of LPS-mediated IL-6 and TNF-α mRNA. In addition, it significantly reduced the phosphorylation levels of NF-κB subunit p65 in a concentration-dependent manner and suppressed translocation of NF-κB p65 into the nucleus. Furthermore, grossamide markedly attenuated the LPS-induced expression of Toll-like receptor 4 (TLR4) and myeloid differentiation factor 88 (MyD88). Taken together, these data suggest that grossamide could be a potential therapeutic candidate for inhibiting neuroinflammation in neurodegenerative diseases.

Chemical constituents from Cordia alliodora and C. colloccoca (Boraginaceae) and their biological activities.

Two new natural products, 5-O-[ß-D-apiofuranosyl-(1→6)-ß-d-glucopyranosyl]-1-isoindolinone (1) as well as N-(2E)-3-[(2S,3R)-2-(4-hydroxy-3-methoxyphenyl)-3-(hydroxymethyl)-7-methoxy-2,3-dihydro-1-benzofuran-5-yl]acryloylglycine (2), along with four known compounds (3-6), were isolated from the methanolic extract of Cordia alliodora root bark. Furthermore, the methanolic extract of Cordia colloccoca leaves, afforded the known flavonoids afzelin (7) and quercitrin (8). The isolated secondary metabolites were assayed for their antimicrobial activities against a panel of 6g positive and negative bacteria and three human pathogenic fungi. Moreover, their antiproliferative effect was also evaluated in vitro against the human non-small-cell bronchopulmonary carcinoma line NSCLC-N6, the epidermoid lung cancer cell line A549 as well as the normal human skin fibroblast cell line (AG01523).

Anti-inflammatory lignanamides from the roots of Solanum melongena L.

Four new lignanamides, melongenamides A-D (1-4), together with six known ones (5-10), were isolated from the roots of Solanum melongena L. Their structures were elucidated on the basis of 1D and 2D NMR experiments and by comparison of their spectroscopic and physical data with the literature values. Compounds 2-8 exhibited inhibitions of nitric oxide production in lipopolysaccharide-induced RAW 264.7 macrophages with IC50 values ranging from 16.2 to 58.5 µM.

A new flavonol C-glycoside and a rare bioactive lignanamide from Piper wallichii Miq. Hand.-Mazz.

This study was conducted to investigate the chemical constituents of Piper wallichii (Miq.) Hand.-Mazz. and evaluate their biological activity. Compounds were isolated by various column chromatographic methods, and their structures were elucidated on the basis of physical characteristics and spectral data. The 1, 1-diphenyl-2-picrylhydrazyl (DPPH)-scavenging activity and acetylcholinesterase (AChE)-inhibitory activity of the compounds were evaluated. Five compounds were obtained and identified as 8-C-ß-D-glucopyranosylkaempferol-3-O-ß-D-glucopyranoside (1), 1, 2-dihydro-6,8-dimethoxy-7-hydroxy-1-(3, 5-dimethoxy-4-hydroxyphenyl)-N(1), N(2)-bis-[2-(4-hydroxyphenyl)ethyl]-2, 3-naphthalene dicarboxamide (2), goniothalactam (3), aristololactam A IIIa (4) and piperlonguminine (5). Compound 1 was a new flavonol C-glycoside, 2 was a rare lignanamide, which was isolated from the family Piperaceae for the first time, and compound 3 was isolated from this plant for the first time. Among them, 2 showed potent DPPH-scavenging activity, with IC50 of 31.38 ± 0.97 µmol·L(-1); Compounds 2, 3, and 4 showed AChE inhibitory activity at 100 µmol·L(-1), with inhibition rates of 28.57% ± 1.47%, 18.48% ± 2.41% and 17.4% ± 3.03%, respectively.

A new flavonol C-glycoside and a rare bioactive lignanamide from Piper wallichii Miq. Hand.-Mazz / 中国天然药物

This study was conducted to investigate the chemical constituents of Piper wallichii (Miq.) Hand.-Mazz. and evaluate their biological activity. Compounds were isolated by various column chromatographic methods, and their structures were elucidated on the basis of physical characteristics and spectral data. The 1, 1-diphenyl-2-picrylhydrazyl (DPPH)-scavenging activity and acetylcholinesterase (AChE)-inhibitory activity of the compounds were evaluated. Five compounds were obtained and identified as 8-C-β-D-glucopyranosylkaempferol-3-O-β-D-glucopyranoside (1), 1, 2-dihydro-6,8-dimethoxy-7-hydroxy-1-(3, 5-dimethoxy-4-hydroxyphenyl)-N(1), N(2)-bis-[2-(4-hydroxyphenyl)ethyl]-2, 3-naphthalene dicarboxamide (2), goniothalactam (3), aristololactam A IIIa (4) and piperlonguminine (5). Compound 1 was a new flavonol C-glycoside, 2 was a rare lignanamide, which was isolated from the family Piperaceae for the first time, and compound 3 was isolated from this plant for the first time. Among them, 2 showed potent DPPH-scavenging activity, with IC50 of 31.38 ± 0.97 μmol·L(-1); Compounds 2, 3, and 4 showed AChE inhibitory activity at 100 μmol·L(-1), with inhibition rates of 28.57% ± 1.47%, 18.48% ± 2.41% and 17.4% ± 3.03%, respectively.