Self-assembled core-shell nanoparticles with embedded internal standards for SERS quantitative detection and identification of nicotine released from snus products.

Surface enhanced Raman spectroscopy (SERS) is a unique analytical technique with excellent performance in terms of sensitivity, non-destructive detection and resolution. However, due to the randomness and poor repeatability of hot spot distribution, SERS quantitative analysis is still challenging. Meanwhile, snus is a type of tobacco product that can release nicotine and other components in the mouth without burning, and the rapid detection technique based on SERS can reliably evaluate the amount of nicotine released from snus, which is of great significance for understanding its characteristics and regulating its components. Herein, the strategy was proposed to solve the feasibility of SERS quantitative detection based on self-assembled core-shell nanoparticles with embedded internal standards (EIS) due to EIS signal can effectively correct SERS signal fluctuations caused by different aggregation states and measurement conditions, thus allowing reliable quantitative SERS analysis of targets with different surface affinity. By means of process control, after the Au nanoparticles (Au NPs) were modified with 4-Mercaptobenzonitrile (4-MBN) as internal standard molecules, Ag shell with a certain thickness was grown on the surface of the AuNP@4-MBN, and then the Au@4-MBN@Ag NPs were used to regulate and control the assembly of liquid-liquid interface. The high-density nano-arrays assembled at the liquid-liquid interface ensure high reproducibility as SERS substrates, and which could be used for SERS detection of nicotine released from snus products. In addition, time-mapping research shows that this method can also be used to dynamically monitor the release of nicotine. Moreover, such destruction-free evaluation of the release of nicotine from snus products opens up new perspectives for further research about the impact of nicotinoids-related health programs.

Cytotoxic sesquiterpene aryl esters from Armillaria gallica 012m.

Objective: To study the chemical constituents of the EtOAc extract of Armillaria gallica 012m. Methods: The chemical constituents of the EtOAc extract of A. gallica 012m were isolated and purified by various column chromatography and their structures were elucidated on the basis of the 1D and 2D NMR spectroscopic and HRESIMS data. Cytotoxicity of all isolates against A549, HCT-116, M231 and W256 human tumor cells was determined by the MTT method. Results: A new sesquiterpene aryl ester, armimelleolide C (1), and eight known ones including armillarivin (2), melleolide F (3), 6'-chloromelleolide F (4), melleolide (5), melleolide K (6), melledonol (7), 13-hydroxydihydromelleolide (8), and armillane (9), were isolated from the EtOAc extract of A. gallica 012m. All isolates showed potential cytotoxic activities against at least one of the human cancer cell lines with IC50 values ranging from (3.17 ± 0.54) to (17.57 ± 0.47) µmol/L. Compound 1 showed significant inhibitory activity against M231 with an IC50 value of (7.54 ± 0.24) µmol/L compared with paclitaxel as the positive control. Compounds 2, 3, and 7, 9 showed obvious inhibitory activity against HCT-116 and were better than that of the positive control. Conclusion: The chemical constituents including a new sesquiterpene aryl ester armimelleolide C (1) from the EtOAc extract of A. gallica 012m have a variety of structures and potential antitumor activities.

Integrative analysis of sensory evaluation and non-targeted metabolomics to unravel tobacco leaf metabolites associated with sensory quality of heated tobacco.

Introduction: Heated tobacco (Nicotiana tabacum L.) products are heating tobacco plug at a temperature of 350°C and produce different emissions in aerosol and sensory perceptions of tobacco leaf compared with combustible tobacco. Previous study assessed different tobacco varieties in heated tobacco for sensory quality and analyzed the links between sensory scores of the final products and certain chemical classes in tobacco leaf. However, contribution of individual metabolites to sensory quality of heated tobacco remains largely open for investigation. Methods: In present study, five tobacco varieties were evaluated as heated tobacco for sensory quality by an expert panel and the volatile and non-volatile metabolites were analyzed by non-targeted metabolomics profiling. Results: The five tobacco varieties had distinct sensory qualities and can be classified into higher and lower sensory rating classes. Principle component analysis and hierarchical cluster analysis showed that leaf volatile and non-volatile metabolome annotated were grouped and clustered by sensory ratings of heated tobacco. Orthogonal projections to latent structures discriminant analysis followed by variable importance in projection and fold-change analysis revealed 13 volatiles and 345 non-volatiles able to discriminate the tobacco varieties with higher and lower sensory ratings. Some compounds such as ß-damascenone, scopoletin, chlorogenic acids, neochlorogenic acids, and flavonol glycosyl derivatives had strong contribution to the prediction of sensory quality of heated tobacco. Several lyso-phosphatidylcholine and lyso-phosphatidylethanolamine lipid species, and reducing and non-reducing sugar molecules were also positively related to sensory quality. Discussion: Taken together, these discriminating volatile and non-volatile metabolites support the role of leaf metabolites in affecting the sensory quality of heated tobacco and provide new information on the types of leaf metabolites that can be used to predict applicability of tobacco varieties for heated tobacco products.

Simultaneous extraction and surface enhanced Raman spectroscopy detection for the rapid and reliable identification of nicotine released from snus products.

Surface enhanced Raman spectroscopy (SERS) is a highly sensitive analytical detection technique that provides unique chemical and structural information on target molecules. Here, simultaneous extraction and SERS detection of nicotine for the rapid and reliable identification of nicotine released from snus products were performed based on a nano-Au assembly hierarchy structure in the capillary. Based on this strategy, the time evolution of the concentrations of nicotine released from the snus products was measured. Through comparison of the intensities of the spectral peaks of the symmetrical breathing of the pyridine moiety of nicotine molecules, with the prolongation of time, the concentration of nicotine released decreased significantly, which is helpful for establishing a method for the rapid evaluation of the processing and selection of excipients of snus products, and provides a new idea for further study of the production of snus pouches and related tobacco products. Moreover, based on data fitting, it can be calculated that the concentration of nicotine in the extraction presented an obvious quadratic relationship with time, and the release of most of the nicotine in the snus pouch, which is held through the gums and palate, was basically completed after ∼15 min. Such destruction-free simultaneous measurements of snus products are opening up new perspectives for further research about the impact of nicotinoids on smokers' health and cessation programs.

New isolates from leaves of Nicotiana tabacum and their biological activities.

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.

Four New Minor Compounds from Seeds of Plantago asiatica.

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.

Plasiatine, an Unprecedented Indole-Phenylpropanoid Hybrid from Plantago asiatica as a Potent Activator of the Nonreceptor Protein Tyrosine Phosphatase Shp2.

Plasiatine (1), isolated from the seeds of Plantago asiatica, is an unprecedented indole analogue linked to a phenylpropanoid moiety via a carbon bond that builds up a novel heteromeric construction with a C19N2 scaffold. Its structure was determined by spectroscopic data and computational evidence. Notably, experimental assay demonstrated that 1 significantly enhanced the activity of the nonreceptor protein tyrosine phosphatase Shp2 in vitro in a concentration-dependent manner with an EC50 value of 0.97 µM, and activated phosphorylation of ERK, a known target of Shp2. Moreover, plasiatine (1) promoted hepatocellular HepG2 cells migration. Molecular docking suggested that plasiatine (1) binds to the catalytic cleft of Shp2. These results identified plasiatine (1) as the first small molecule Shp2 activator, and it warrants further investigation as a novel pharmaceutical tool to study the function of Shp2 in tumorigenesis.

Antiviral sesquiterpenes from leaves of Nicotiana tabacum.

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%.

LC-UV-Guided Isolation and Structure Determination of Lancolide E: A Nortriterpenoid with a Tetracyclo[5.4.0.0(2,4).0(3,7)]undecane-Bridged System from a "Talented" Schisandra Plant.

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.

Aspergillines A-E, highly oxygenated hexacyclic indole-tetrahydrofuran-tetramic acid derivatives from Aspergillus versicolor.

Aspergillines A-E (1-5) are highly oxygenated cyclopiazonic acid (CPA)-derived alkaloids bearing a rigid and sterically congested hexacyclic indole-tetrahydrofuran-tetramate scaffold, isolated from the endophytic fungus Aspergillus vesicolor. Apergillines A-C represent a new subclass of CPA-derived alkaloids, and aspergillines B and E possess a butanoic acid methyl ester moiety. The structures, including absolute configuration, were elucidated by interpretation of the NMR, X-ray crystallographic, and circular dichroism data. All compounds displayed anti-TMV and cytotoxic activities.

Biphenyls from Nicotiana tabacum and their anti-tobacco mosaic virus.

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.

Structural characterization and antioxidative activity of lancifonins: unique nortriterpenoids from Schisandra lancifolia.

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.

Structure and bioactivity of triterpenoids from the stems of Schisandra sphenanthera.

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 µg ml(-1) and therapeutic index value of 117.12.

Bioactive lignans from the leaves and stems of Schisandra wilsoniana.

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 microg/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.

Six new lignans from the leaves and stems of Schisandra sphenanthera.

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.

Phenolic constituents from Parakmeria yunnanensis and their anti-HIV-1 activity.

Three new phenolic compounds, yunnanensins A-C (1-3), together with fourteen known ones (4-17), were isolated from the leaves and stems of Parakmeria yunnanensis. The structures of new compounds were established on the basis of extensive spectroscopic analyses. Several compounds showed weak anti-HIV-1 activity.

Schisphenlignans A-E: five new dibenzocyclooctadiene lignans from Schisandra sphenanthera.

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.

Bioactive phenolics and terpenoids from Manglietia insignis.

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.

Kadcoccitones A and B, two new 6/6/5/5-fused tetracyclic triterpenoids from Kadsura coccinea.

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.

Lanostane triterpenoids from the stems of Schisandra glaucescens.

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.