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High-speed counter-current chromatography (HSCCC) combined with macroporous resin (MR) column was successfully applied to the isolation and purification of four flavonoid glycosides from the medicinal herb Lotus plumule (LP). A polar two-phase solvent system composed of ethyl acetate-n-butanol-water (1:2:3, v/v/v) was selected by high-performance liquid chromatography (HPLC) and run on a preparative scale where the lower aqueous phase was used as the mobile phase with a head-to-tail elution mode. Quercetin-3-O-β-D-glucopyranoside (15 mg), isorhamnetin-3-O-β-D-glucopyranoside (13 mg), apigenin 6-C-β-D-glucopyranosyl-8-C-α-L-arabinopyranoside (18 mg) and apigenin 6,8-di-C-β-D-glucopyranoside (48 mg) were obtained in a one-step HSCCC separation from 240 mg of the sample. The purity of each compound was over 95% as determined by HPLC. Chemical structures of the isolated compounds were identified by electrospray ionization mass spectrometry (ESI-MS-MS) and nuclear magnetic resonance (NMR) methods. Moreover, the four compounds were isolated from LP for the first time., (© The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Oxidative stress has been considered as a major cause of cell damage in various neurodegenerative disorders. One of the reasonable strategies for delaying the disease's progression is to prevent reactive oxygen species (ROS) mediated cellular injury by dietary or pharmaceutical augmentation of free radical scavengers. Isocampneoside II (ICD) is an active phenylethanoid glycoside isolated from the medicinal hardwood genus Paulownia. This study was designed to explore free radical scavenging potential of ICD in different in vitro systems and its protective role in hydrogen peroxide (H₂O₂)-induced oxidative stress and apoptotic death in cultured rat pheochromocytoma (PC12) cells. The results showed ICD eliminated approximately 80.75% superoxide radical at the concentration of 0.1mg/ml and inhibited metal chelating by 22.07% at 8 mg/ml. Additionally, ICD showed a strong ability on reducing power and provided protection against oxidative protein damage induced by hydroxyl radicals. Pretreatment of PC12 cells with ICD prior to H₂O₂ exposure elevated cell viability, enhanced activity of superoxide dismutase and catalase, and decreased levels of malondialdehyde and intracellular ROS. Furthermore, ICD inhibited cell apoptosis and Bax/Bcl-2 ratio induced by H₂O₂. These findings suggested ICD may be considered as a potential antioxidant agent and should encourage for further research in neurodegenerative diseases., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Study on the EtOAc soluble fraction from the bark of Populus ussuriensis Kom. resulted in the isolation of three phenolic glycosides, including populoside (1), 7-O-ρ-coumaroylsalirepin (2) and 7-O-caffeoylsalirepin (3), among which 3 is a new compound. The structures of these compounds were elucidated on the basis of spectroscopic evidence. Phenolic glycosides 1-3 exhibited excellent antioxidant activity, evaluated in the ABTS⁺ radical scavenging assay.

Four epimeric phenylethanoid glycosides, including a new one, R,S-beta-ethoxy-beta-(3,4-dihydroxyphenyl)-ethyl-O-alpha-L-rhamnopyranosyl(1-->3)-beta-D-(6-O-E-caffeoyl)-glucopyranoside named isoilicifolioside A (1), and three known compounds, ilicifolioside A (2), campneoside II (3), and isocampneoside II (4), were isolated from Paulownia tomentosa var. tomentosa wood. The structures of the four compounds were elucidated by the interpretation of 1D and 2D NMR and MS spectra. This is the first report of the chemical profile of this tree. Compounds 1-4 exhibited excellent anti-complement activity with IC(50) values less than 74 microM, compared with tiliroside (IC(50) = 104 microM) and rosmarinic acid (IC(50) = 182 microM) that were used as positive controls.

Study on the water soluble fraction from the leaves of Paulownia coreana led to the isolation of verbascoside (1), isoverbascoside (2), campneoside II (3), and a new phenylpropanoid glycoside, (R,S)-7-hydroxy-7-(3,4-dihydroxyphenyl)-ethyl-O-alpha-L-rhamnopyranosyl(1 --> 3)-beta-d-(6-O-caffeoyl)-glucopyranoside (4). The structures of these compounds were established on the basis of spectroscopic evidence.