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Three new 14-noreudesmane sesquiterpenes ( 1 ⿿ 3 ) as well as four known ones ( 4 ⿿ 7 ) were isolated from the leaves of Nicotiana tabacum . Their structures were determined mainly by spectroscopic methods, including extensive 1D- and 2D NMR techniques. Compounds 1⿿7 were evaluated for their anti-tobacco mosaic virus (anti-TMV) activities. The results showed that compound 1 exhibited moderate anti-TMV activity with inhibition rate of 46.7%, which were higher than that of positive control (ningnanmycin).

Lancolide E (1) featuring a complex tetracyclo[5.4.0.0(2,4).0(3,7)]undecane-bridged system that is constructed by an eight-, a three-, and two five-membered carbon rings in a sterically congested region was obtained in trace amounts from a "talented" schinortriterpenoid producer Schisandra lancifolia. Its structure was fully characterized by combining 2D NMR spectroscopy, theoretical calculations, and X-ray diffraction analysis. The biogenetic pathway of 1 was proposed to involve a Prins cyclization.

Three new isolates (1−3) including one new sterol and two new flavonoids together with three known sterols (4−6) were isolated from the leaves of Nicotiana tabacum. Their structures were determined mainly by spectroscopic methods, including extensive 1D and 2D NMR techniques. All compounds were evaluated for their anti-tobacco mosaic virus and cytotoxic activities. The results showed that compounds 2 and 3 exhibited high anti-TMV activity with inhibition rate of 34.2 and 33.4%, respectively, which were roughly equivalent to that of positive control. The cytotoxicities of compounds 1 and 4–6 against five human tumour cell lines were also tested, and tested compounds showed weak inhibitory activities against some tested human tumour cell lines.

In this paper, Cu-doped carbon quantum dots (Cu-CQDs) were prepared by carrying out thermolysis of Na2[Cu(EDTA)] and hydroxylamine hydrochloride at 300 ºC for 2 h. The as-prepared Cu-CQDs were characterized by UV-Vis, Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The Cu-CQDs exhibited good fluorescence property, high stability, excitation-dependent emission behavior and a quantum yield of 9.8%. More significantly, the synthesized Cu-CQDs were developed for sensing rutin (RT) based on the fluorescence quenching of the prepared Cu-CQDs. A good linear relationship between the fluorescence quenching of Cu-CQDs and different concentrations of RT was obtained in the range of 0.1-15 µg mL-1 with a correlation coefficient of 0.9959. The detection limit was as low as 0.05 µg mL-1 (signal-to-noise ratio, S/N = 3). The possible mechanism of fluorescence quenching was explored, which was proved to be inner filter effect. Importantly, the proposed method was successfully applied in the detection of RT tablet samples and with satisfactory results, showing the practical applications.

Three new flavone derivatives, paranicflavones A–C (1–3), together with three known similar compounds (4–6), were isolated from their roots and stems of Tiandeng tobacco. Their structures were elucidated by spectroscopic methods, including extensive 1H and 13C NMR techniques. Additionally, compounds 1–6 were evaluated for their anti-tobacco mosaic virus (anti-TMV) activities, and compound 2 exhibited anti-TMV activity with inhibition rate of 35.8%, which is higher than that of positive control, ningnanmycin.

Five new biphenyls, tababiphenyls A-E (1-5), together with five known ones (5-10), were isolated from the leaves of Nicotiana tabacum, of which compound 1 possessed a seldom reported 6-carbons unit in biphenyls. Their structures were established on the basis of extensive spectroscopic analyses. All compounds were tested for their anti-tobacco mosaic virus (anti-TMV) activities. The results showed that compounds 3 and 5 exhibited high anti-TMV activities with inhibition rate of 48.4% and 32.1%, respectively, which were higher than that of positive control (ningnanmycin). The other compounds also showed potential anti-TMV activities with inhibition rates in the range of 18.6-28.7%, respectively. (C) 2014 Elsevier B.V. All rights reserved.

Three new phenolic amides, tabamides A-C (1-3), together with three known phenolic amides (4-6), were isolated from the leaves of Nicotiana tabacum. Their structures were elucidated by spectroscopic methods, including extensive 1D- and 2D NMR techniques. Compounds 1-6 were also tested for their anti-tobacco mosaic virus (anti-TMV) activity. The results showed that compound 1 exhibited high anti-TMV activity with inhibition rate of 38.6%, which is higher than that of positive control (ningnanmycin). The other compounds also showed potential anti-TMV activity with inhibition rates in the range of 15.3-26.5%, respectively. (C) 2014 Published by Elsevier B.V. on behalf of Phytochemical Society of Europe.

Six new lignans (1-6), as well as five known ones (7-11) were isolated from the leaves and stems of Schisandra chinensis. The structures of 1-6 were established on the basis of spectroscopic methods including 1D-and 2D-NMR techniques and CD experiments. Compound 1 was the first example of naturally occurring N-containing lignans featuring a nicotinoyl group. All the new compounds were evaluated for their anti-HIV-1 activities and showed EC50 values in the range 17.89-138.23 mu g/mL.

Five new nortriterpenoids, schicagenins D-F (1-3, resp.) and negleschidilactones A and B (4 and 5, resp.), together with eleven known ones, were isolated from the stems of Schisandra neglecta. Their structures were established on the basis of extensive spectroscopic analyses. All the compounds were evaluated for their activities regarding insulin sensitivity in 3T3-L1 differentiated adipocytes. None of them showed a significant bioactivity at 10M concentration.

Two new triterpenoids, schisphendilactone A and B (1 and 2), together with three known triterpenoids, were isolated from the stems of Schisandra sphenanthera. Their structures were elucidated by spectroscopic methods, and the absolute configuration of 1 was determined by single-crystal X-ray diffraction. Compound 2 showed moderate inhibitory activity against SW480 cancer cell line, and compound 5 exhibited promising anti-HIV-1 activity with EC50 value of 0.52 mu g ml(-1) and therapeutic index value of 117.12.

Six new lignans, schisphenlignans F-K (1-6), together with ten known ones, were isolated from the leaves and stems of Schisandra sphenanthera. Their structures were elucidated on the basis of spectroscopic methods, including extensive NMR, MS and CD spectra. In addition, some compounds were tested for their acute activity on insulin sensitivity in 3T3-L1 differentiated adipocytes and anti-HIV-1 activity. (C) 2013 Elsevier B.V. All rights reserved.

Four new tetrahydrofuran lignans, schpropinrins A-D (1–4), together with five known ones, were isolated from the leaves and stems of Schisandra propinqua var. sinensis. Their structures, including absolute configurations, were characterized by means of spectroscopic analysis and ECD calculation. Compounds 1–4 featured a ketal or hemiketal substructure at C-7 and all of the isolates were tested for their anti-HIV integrase activity. Electronic Supplementary Material Supplementary material is available for this article at 10.1007/s13659-013-0017-8 and is accessible for authorized users.

Five new dibenzocyclooctadiene lignans, schisphenlignans A-E (1-5), together with eight known ones, were isolated from the stems of Schisandra sphenanthera. The structures of 1-5 were elucidated based on the analysis of their NMR, MS and circular dichroism (CD) spectra. Some isolates were tested for their acute activities on insulin sensitivity in 3T3-L1 differentiated adipocytes, but none of them showed significant bioactivity with 10 µM administration of the tested compounds.

Four new indole alkaloids, plasiaticines A-D (1–4), together with two known ones, were isolated from the seeds of Plantago asiatica. The structures of the new compounds were elucidated on the basis of comprehensive analysis of spectroscopic data. All compounds were tested for their cytotoxic activity, and all compounds except 4 were tested for their acetylcholinesterase (AChE) inhibitory activities.

Two new neolignans, manneoinsigins A (1) and B (2), together with four known lignans, were isolated from the leaves and stems of Manglietia insignis. The new compounds were established on the basis of extensive spectroscopic analyses. All compounds except 2 were tested for their cytotoxic activity. Compound 3 showed weak cytotoxic activity against the HL-60 human tumor cell line with the IC50 value of 23.5 µM.

Neolaxiflorin A (1), an unprecedented ent-kaurane diterpenoid with a bicyclo[3.1.0]hexane unit, and its seco-derivative, neolaxiflorin B (2), along with two known compounds 3 and 4 were isolated from the leaves of Isodon eriocalyx var. laxiflora. The absolute configuration of 1 was determined by spectral methods and single crystal X-ray diffraction analysis. Compound 4 and the synthesized compound 5 exhibited significant cytotoxicity.

Four new highly oxygenated nortriterpenoids, lancifodilactones O-R (1-4), together with six known ones, i.e., 5-10, were isolated from the leaves and stems of Schisandra lancifolia. Their structures were elucidated by spectroscopic analyses, including 1D- and 2D-NMR experiments and mass spectrometry. Compounds 1-3 were evaluated for their cytotoxicity against NB4, A549, SHSY5Y, PC-3, and MCF-7 cell lines. No compounds exhibited significant cytotoxicity, the I(C5)0 values being above 50 mu M.

Three unreported sesquiterpenes possessing two new skeletons, tabasesquiterpenes A-C (1-3), together with three known sesquiterpenes (3-6) were isolated from the leaves of Nicotiana tabacum. Their structures were determined mainly by spectroscopic methods, including extensive 1D- and 2D-NMR techniques. Compounds 1-6 were evaluated for their anti-tobacco mosaic virus (anti-TMV) activities. The results showed that compound 2 exhibited high anti-TMV activity with inhibition rate of 35.2%, which were higher than that of positive control (ningnanmycin). The other compounds also showed potential anti-TMV activity with inhibition rates in the range of 20.5-28.6%.

Six new lignans (I), (II), (III), and (IV) are isolated along with five known ones from the leaves and stems of Schisandra chinensis.

The isolation, structure elucidation and determination of the absolute configuration of six lancifonins are described.

Six unique nortriterpenoids, lancifonins A-F (1-6), were isolated from Schisandra lancifolia. Their absolute configurations were determined by X-ray diffraction and ECD calculation. The conformational analysis of 1 was performed due to the unanticipated changes of Cotton effects in its ECD spectrum. Compounds 5 and 6 possess a unique 7/7 fused carbocyclic core with an internal ester bridge between C-9 and C-14, and 5 exhibited protective activity against H2O2-induced oxidative damage on Caco-2 cells.

A pair of new triterpenoid epimers, kadcoccitones A (1) and B (2), together with a new biogenetically related compound kadcoccitone C (3), were isolated from Kadsura coccinea. The epimers featured an unprecedented carbon skeleton with a 6/6/5/5-fused tetracyclic ring system unit and a C(9) side chain. Their structures were determined by spectroscopic data, ECD calculation, and single-crystal X-ray diffraction. Compounds 1 and 3 showed anti-HIV-1 activity with an EC(50) value of 47.91 and 32.66 μg/mL, respectively.

Four new compounds, a dibenzylbutane lignin, plasiaticine F (1), an acetylenic glycoside, plasiaticine G (2), an indole alkaloid, plasiaticine H (3), and an ionone derivative, plasiaticine I (4), were isolated from the seeds of Plantago asiatica. The structures of the new compounds were elucidated on the basis of comprehensive analysis of spectroscopic data. Compounds 1–3 were tested for their cytotoxicity, but lacked significant activity.

Four new compounds, maninsigins A-D (1-4), including two new neolignans (1-2) and two new sesquiterpenes (3-4), as well as ten known compounds (5-14), were isolated from the leaves and stems of Manglietia insignis. Their structures were established on the basis of extensive spectroscopic analyses. In addition, some compounds were tested for their cytotoxic and neurite outgrowth-promoting activities, as well as their antagonistic activity toward FXR ligand. (c) 2012 Elsevier B.V. All rights reserved.

Ten new triterpenoids, schiglausins A-J (1-10), as well as four known compounds, were isolated from the stems of Schisandra glaucescens. Their structures were elucidated on the basis of spectroscopic methods, including extensive NMR spectra and CD experiment. Compound 8 was determined to be a norlanostane triterpenoid. The crystal structure of compound 1 has been determined using single-crystal X-ray analysis while its absolute configuration was assigned on the basis of the CD spectrum. All isolates were tested for their FXR agonistic and antagonistic effects.

This study investigated the 70% aqueous acetone extract of the fruits of Schisandra rubriflora which led to the isolation of eight lignans, including a new isolate, rubrisandrin C (1), and seven known lignans (2-8). The structure of 1 was established by extensive 1D and 2D NMR spectroscopy and its absolute stereochemistry was determined by CD spectrum. Compounds 1-5 and 7-8 were evaluated for their anti-HIV-1 activity that showed inhibitory activity on HIV-1(IIIB) induced syncytium formation with EC(50) values in the range of 2.26 approximately 20.4 microg/mL. Compounds 1 and 7 exerted their obvious protection of HIV-1(IIIB) inducted MT-4 host cells lytic effects with a selectivity index of 15.4 and 24.6, respectively.

Three new dibenzocyclooctadiene lignans, marlignans M–O (1–3), together two known ones, were isolated from the leaves and stems of Schisandra wilsoniana. The structures of 1–3 were elucidated by spectroscopic methods, including extensive 1D- and 2D-NMR techniques. Compound 2 showed anti-HIV-1 activity with an EC50 value of 5.82 μg/mL and a therapeutic index (TI) of more than 12.8. Compound 3 showed obvious bioactivity in inhibiting Epstein-Barr virus early antigen (EBV-EA) activation.