Nine new neolignan glycosides (1-9), viburfordosides A-I, two new neolignans, fordianes A and B (10, 11), and seven known analogues (12-18) have been isolated and identified from the fruits of Viburnum fordiae Hance. The structures and absolute configurations of undescribed neolignan constituents were identified by chemical methods and spectroscopic analyses. The α-glucosidase inhibitory, ABTS and DPPH scavenging, and anti-inflammatory activities of these secondary metabolites were evaluated. Some of them exhibited significant potency in inhibiting α-glucosidase and scavenging free radicals. Among the 14 metabolites that were found to have the capacity to inhibit NO production in LPS-stimulated RAW264.7 macrophage cells, compounds 2, 4, 6, 10, 11, 14, 17, and 18 were potent with IC values of 10.88-41.10 μM. These results support that V. fordiae fruits possessing the neolignan compounds may serve as both a functional food and a medicinal resource to prevent and treat type 2 diabetes (T2D).
Two new phenolic glycoside compounds (1, 2) and ten known analogues (3-12) have been isolated from the ethanolic extract of Brassica rapa flowers and identified as 2-O-β-d-glucopyranosyl-(1S)-(4-methoxyphenyl)ethylene glycol (1), 2-(4-O-β-d-allopyranosyl)phenyl-ethanol (2), 2-O-β-d-glucopyranosyl-(1S)-phenylethylene glycol (3), 2-O-β-d-glucopyranosyl-(1R)-phenylethylene glycol (4), (Z)-p-coumaryl-O-β-d-glucopyranoside (5), phenyl-O-β-d-glucopyranoside (6), 2-phenylethyl-O-β-d-glucopyranoside (7), salidroside (8), 2-(2-hydroxyphenyl)ethanol-O-β-d-glucopyranoside (9), 4-methoxybenzyl-O-β-d-glucopyranoside (10), 2,4,6-trimethoxyphenyl-1-O-β-d-glucopyranoside (11) and sachaliside 1 (12). The structures of 1 and 2, including absolute configurations, were determined by spectroscopic data (H NMR, C NMR, HSQC, HMBC and ORD) and chemical methods. In addition, most of them exhibited inhibitory activity with IC values ranging from 14.43 to 50.20 μM in comparison to the positive control acarbose (IC = 15.76 μM) in intestinal α-glucosidase inhibitory activity tests.
Coordination-driven self-assembly is a powerful approach for the construction of metallosupramolecules, but designing coordination moieties that can drive the self-assembly with high selectivity and specificity remains a challenge. Here we report two ortho-modified terpyridine ligands that form head-to-tail coordination complexes with Zn(II). Both complexes show narcissistic self-sorting behaviour. In addition, starting from these ligands, we obtain two sterically congested multitopic ligands and use them to construct more complex metallo-supramolecules hexagons. Because of the non-coaxial structural restrictions in the rotation of terpyridine moieties, these hexagonal macrocycles can hierarchically self-assemble into giant cyclic nanostructures via edge-to-edge stacking, rather than face-to-face stacking. Our design of dissymmetrical coordination moieties from congested coordination pairs show remarkable self-assembly selectivity and specificity.
The ethanolic extract of the stems of Viburnum fordiae Hance showed insecticidal and α-glucosidase inhibitory activities and then was fractionated by bioactivity-guided fractionation to obtain a rare C-norisoprenoid (1), together with a new phenolic glycoside (2), and seven known compounds, alangionoside C (3), pisumionoside (4), koaburaside (5), 3,5-dimethoxy-benzyl alcohol 4-O-β-d-glucopyranoside (6), 3,4,5-trimethoxybenzyl-β-d-glucopyranoside (7), arbutin (8), and salidroside (9). The previously undescribed compounds were elucidated as (3R,9R)-3-hydroxy-7,8-didehydro-β-ionyl 9-O-α-d-arabinopyranosyl-(1→6)-β-d-glucopyranoside (1) and 2-(4-O-β-d-glucopyranosyl)syringylpropane-1,3-diol (2) by spectroscopic data (H and C NMR, HSQC, HMBC,H-H COSY, HSQC-TOCSY, HRESIMS, IR and ORD) and chemical methods. Compound 1 showed potent insecticidal effect against Mythimna separata with LD value of 140 μg g. Compounds 2, 5, 6, 8 and 9 showed varying α-glucosidase inhibitory activity with IC values ranging from 148.2 to 230.9 μM.
The
syntheses of 4′-substituted chiral 2,2′:6′,2″-terpyridine
(tpy) ligands with predetermined configurations and directionalities
are rather limited in the supramolecular chemistry field. In this
study, a carbazole-linked ditopic chiral ligand L was
synthesized using 4′-bromo-substituted pineno-fused tpy 5 as the precursor. Upon complexation with Cd(NO3)2·4H2O and Zn(NO3)2·6H2O, two enantiomerically pure metallosupramolecules,
[Cd3L3] and [Zn4L4], have
been self-assembled and characterized by NMR, electrospray ionization-mass
spectrometry, traveling wave ion mobility-mass spectrometry, and DOSY
analysis. In addition, their optical properties are characterized
by UV–vis, fluorescence, circular dichroism, and circularly
polarized luminescence, suggesting an efficiency transmission and
amplification of chirality from the ligand to metal center via self-assembly.
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