Assessment of anti-inflammatory properties of extracts from Honeysuckle (Lonicera sp. L., Caprifoliaceae) by ATR-FTIR spectroscopy

Salvadora persica leaves: phytochemical profile and in vitro-inhibitory activity on inflammatory mediators implicated in periodontal disease

CONTEXT

Virtually all parts of Salvadora persica L. (Salvadoraceae) are used in traditional medicine. The twigs and leaves are used for oral health, but leaves are far less investigated.

OBJECTIVE

This study assesses the oral health-promoting potential of S. persica leaves with emphasis on anti-inflammatory and antiproliferative effects and provides an in depth-characterization of their metabolite profile.

MATERIALS AND METHODS

Hot-water and methanolic S. persica leaf extracts (1, 10, and 100 µg/mL) and their major constituents (5, 10, and 50 µM), were subjected to cellular assays on IL-8 and TNFα release in LPS-stimulated human neutrophils, NO-release in LPS/IFNγ stimulated mouse macrophages, and proliferation of HNO97 human tongue carcinoma cells. Metabolite profiling was performed by UHPLC-HRMS analysis. Major constituents were isolated and structurally elucidated.

RESULTS AND DISCUSSION

Both extracts showed pronounced anti-inflammatory activity in LPS-stimulated neutrophils. Major identified compound classes were flavonoid glycosides, the glucosinolate glucotropaeolin, phenyl- and benzylglycoside sulfates, and megastigmane glycosylsulfates, the latter ones identified for the first time in S. persica. Glucotropaeolin strongly inhibited the release of IL-8 and TNF-α (13.3 ± 2.0 and 22.7 ± 2.6% of the release of stimulated control cells at 50 µM), while some flavonoids and 3-(3'-O-sulfo-β-d-glucopyranosyloxy)-7,8-dihydro-β-ionone, a newly isolated megastigmane glycosylsulfate, were moderately active. Benzylisothiocyanate, which is likely formed from glucotropaeolin during traditional application of S. persica, showed considerable antiproliferative activity (IC50 in HNO97 cells: 10.19 ± 0.72 µM) besides strongly inhibiting IL-8 and TNFα release.

CONCLUSIONS

Glucotropaeolin and benzylisothiocyanate are likely implicated in the oral health-promoting effects of S. persica leaves. The chemistry and pharmacology of the newly identified megastigmane glycosylsulfates should be further evaluated.

"Drying effect" of fructus aurantii components and the mechanism of action based on network pharmacology and in vitro pharmacodynamic validation

Background: Fructus aurantii (FA) is the dried, unripe fruit of the plant Citrus aurantium L. and its cultivated varieties. We investigated the drying effect of FA components and how this drying affect is achieved. Methods: We employed systems pharmacology to predict the components and targets of FA that produce its drying effect. These predictions were verified by computer simulation and animal experiments. In the latter, we measured the bodyweight, water consumption, urine output, fecal water content, rate of salivary secretion, and cross-sectional area of the long axis of the submandibular gland of mice. Immunohistochemistry was used to measure expression of aquaporin (AQP)5 in the submandibular gland, AQP2 in the kidney, and AQP3 in the colon. ELISA kits were used to measure the horizontal variation of cyclic adenosine monsophosphate (cAMP), cyclic guanosine monophosphate (cGMP) and interferon-γ. Results: Sixty-seven potentially active components of FA were screened out. FA could produce a drying effect after regulating 214 targets through 66 active components. A total of 870 gene ontology (GO) terms and 153 signaling pathways were identified. The hypoxia inducible factor-1 signaling pathway, phosphoinositide 3-kinase-protein kinase B (PI3K-AKT) signaling pathway, calcium signaling pathway, and Ras signaling pathway may have important roles in the drying effect of FA. Four components of FA were identified: sinensetin, tangeretin, 5-demethylnobiletin and chrysin. These four components could increase the serum level of interferon-γ and ratio of cyclic adenosine monophosphate:cyclic guanosine monophosphate in mice, and affect their water consumption, urine output, fecal water content and rate of salivary secretion. Conclusion: Four components of FA (tangeretin, sinensetin, chrysin, 5-Demethylmobiletin) were closely related to the Janus kinase-signal transducer and activator of transcription-3 (JAK-STAT3), PI3K-AKT, and the other signaling pathways. They can regulate the protein expression of JAK2, STAT3, PI3K, lymphocyte cell-specific protein-tyrosine kinase, vascular endothelial growth factor A, and protein kinase B1, affect water metabolism in the body and, finally, result in a drying effect.

Construction of SNP fingerprint and population genetic analysis of honeysuckle germplasm resources in China

INTRODUCTION

The flower buds of Lonicera japonica Thunb. are widely used in Chinese medicine for their anti-inflammatory properties, and they have played an important role in the fight against SARS COVID-19 and other major epidemics. However, due to the lack of scientific and accurate variety identification methods and national unified standards, scattered and non-standardized management in flower bud production has led to mixed varieties that have caused significant difficulties in the cataloging and preservation of germplasm resources and the identification, promotion, and application of new L. japonica varieties.

METHODS

In this study, we evaluated the population structure, genetic relationships, and genetic fingerprints of 39 germplasm resources of Lonicera in China using simplified genome sequencing technology.

RESULTS

A total of 13,143,268 single nucleotide polymorphisms (SNPs) were identified. Thirty-nine samples of Lonicera were divided into four subgroups, and the population structure and genetic relationships among existing Lonicera germplasm resources were determined using principal component analysis, population structure analysis, and phylogenetic tree analysis. Through several stringent selection criteria, 15 additional streamlined, high-quality DNA fingerprints were filtered out of the validated 50 SNP loci and verified as being able to effectively identify the 39 Lonicera varieties.

DISCUSSION

To our knowledge, this is the first comprehensive study measuring the diversity and population structure of a large collection of Lonicera varieties in China. These results have greatly broadened our understanding of the diversity, phylogeny, and population structure of Lonicera. The results may enhance the future analysis of genetic diversity, species identification, property rights disputes, and molecular breeding by providing a scientific basis and reference data for these efforts.

The First Evidence of Gibberellic Acid's Ability to Modulate Target Species' Sensitivity to Honeysuckle (Lonicera maackii) Allelochemicals

Invasive species employ competitive strategies such as releasing allelopathic chemicals into the environment that negatively impact native species. Decomposing Amur honeysuckle (Lonicera maackii) leaves leach various allelopathic phenolics into the soil, decreasing the vigor of several native species. Notable differences in the net negative impacts of L. maackii metabolites on target species were argued to depend on soil properties, the microbiome, the proximity to the allelochemical source, the allelochemical concentration, or environmental conditions. This study is the first to address the role of target species' metabolic properties in determining their net sensitivity to allelopathic inhibition by L. maackii. Gibberellic acid (GA₃) is a critical regulator of seed germination and early development. We hypothesized that GA₃ levels might affect the target sensitivity to allelopathic inhibitors and evaluated differences in the response of a standard (control, Rbr), a GA₃-overproducing (ein), and a GA₃-deficient (ros) Brassica rapa variety to L. maackii allelochemicals. Our results demonstrate that high GA₃ concentrations substantially alleviate the inhibitory effects of L. maackii allelochemicals. A better understanding of the importance of target species' metabolic properties in their responses to allelochemicals will contribute to developing novel invasive species control and biodiversity conservation protocols and may contribute to applications in agriculture.

Mass spectrometry and synchrotron-FTIR microspectroscopy reveal the anti-inflammatory activity of Bua Bok extracts

INTRODUCTION

Bua Bok or Centella asiatica (CA) is an Asian vegetable with anti-inflammatory benefits. Asiaticoside, asiatic acid, madecassoside and madecassic have been characterised as major active ingredients with a wide range of pharmacological advantages. In manufacturing processes, high-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LCMS) are used to routinely determine the active compounds in raw materials.

OBJECTIVES

This research aims to explore anti-inflammatory properties, characterise metabolites and observe the biochemical changes of the inflammatory induced macrophages after pretreatment with the potential extracted fractions.

METHODS

Bua Bok leaf extracts were prepared. Macrophages were pretreated with non-toxic fractions to determine the anti-inflammatory action. Tentative metabolites of effective fractions were identified by LC-MS. Synchrotron fourier-transform infrared (S-FTIR) microspectroscopy was utilised to observe the biochemical change of the lipopolysaccharide (LPS)-induced cells after pretreatment with potential fractions.

RESULTS

Fractions of ethyl acetate, 30% and 100% ethanol highly increased the nitrile scavenging and suppressed the function of phospholipase A₂ . Fractions of 70% and 100% ethanol strongly decreased nitric oxide production. The comparison of 39 chemical compounds was presented. The change of proteins was improved after pretreatment of macrophages with fraction 70% ethanol. Fraction of 100% ethanol revealed the lipid accumulation was lower than 70% ethanol and diclofenac.

CONCLUSION

While the anti-inflammatory actions of 70% and 100% ethanol were similar. S-FTIR expressed they inhibited inflammatory response with the distinct features of biomolecules. The S-FTIR, LC-MS and biological assay confidently provided the efficient strategies to inform the advantage of herbal extract on cellular organisation instead of a single compound.

Discrimination and Prediction of Lonicerae japonicae Flos and Lonicerae Flos and Their Related Prescriptions by Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy Combined with Multivariate Statistical Analysis

LJF and LF are commonly used in Chinese patent drugs. In the Chinese Pharmacopoeia, LJF and LF once belonged to the same source. However, since 2005, the two species have been listed separately. Therefore, they are often misused, and medicinal materials are indiscriminately put in their related prescriptions in China. In this work, firstly, we established a model for discriminating LJF and LF using ATR-FTIR combined with multivariate statistical analysis. The spectra data were further preprocessed and combined with spectral filter transformations and normalization methods. These pretreated data were used to establish pattern recognition models with PLS-DA, RF, and SVM. Results demonstrated that the RF model was the optimal model, and the overall classification accuracy for LJF and LF samples reached 98.86%. Then, the established model was applied in the discrimination of their related prescriptions. Interestingly, the results show good accuracy and applicability. The RF model for discriminating the related prescriptions containing LJF or LF had an accuracy of 100%. Our results suggest that this method is a rapid and effective tool for the successful discrimination of LJF and LF and their related prescriptions.

A Novel Herbal Extract Blend Product Prevents Particulate Matters-Induced Inflammation by Improving Gut Microbiota and Maintaining the Integrity of the Intestinal Barrier

Air pollutants of PM2.5 can alter the composition of gut microbiota and lead to inflammation in the lung and gastrointestinal tract. The aim of this study was to evaluate the protective effect of a novel herbal extract blend, FC, composed of Lonicera japonica extract, Momordica grosvenori extract, and broccoli seed extract, on PM2.5-induced inflammation in the respiratory and intestinal tract. A549 cells and THP-1 cells, as well as C57BL/6 mice, were stimulated with PM2.5 to establish in vitro and in vivo exposure models. The models were treated with or without FC. The expression of inflammatory cytokines and tight junction proteins were studied. Proteomic analysis was performed to elucidate mechanisms. Mouse feces were collected for gut microbiota analysis. FC was shown to modulate the upregulation of pro-inflammatory cytokines mRNA expression in A549 and THP-1 cells and downregulated tight junction proteins mRNA expression in A549 cells due to PM2.5 stimulation. In animal models, the decreased expression of the anti-inflammatory factor il-10, tight junction protein ZO-1, and the elevated expression of COX-2 induced by PM2.5 were improved by FC intervention, which may be associated with zo-1 and cox-2 signaling pathways. In addition, FC was shown to improve the gut microbiota by increasing the abundance of beneficial bacteria.

Characterization of Constituents with Potential Anti-Inflammatory Activity in Chinese Lonicera Species by UHPLC-HRMS Based Metabolite Profiling

This study centered on detecting potentially anti-inflammatory active constituents in ethanolic extracts of Chinese Lonicera species by taking an UHPLC-HRMS-based metabolite profiling approach. Extracts from eight different Lonicera species were subjected to both UHPLC-HRMS analysis and to pharmacological testing in three different cellular inflammation-related assays. Compounds exhibiting high correlations in orthogonal projections to latent structures discriminant analysis (OPLS-DA) of pharmacological and MS data served as potentially activity-related candidates. Of these candidates, 65 were tentatively or unambiguously annotated. 7-Hydroxy-5,3′,4′,5′-tetramethoxyflavone and three bioflavonoids, as well as three C₃₂- and one C₃₄-acetylated polyhydroxy fatty acid, were isolated from Lonicera hypoglauca leaves for the first time, and their structures were fully or partially elucidated. Of the potentially active candidate compounds, 15 were subsequently subjected to pharmacological testing. Their activities could be experimentally verified in part, emphasizing the relevance of Lonicera species as a source of anti-inflammatory active constituents. However, some compounds also impaired the cell viability. Overall, the approach was found useful to narrow down the number of potentially bioactive constituents in the complex extracts investigated. In the future, the application of more refined concepts, such as extract prefractionation combined with bio-chemometrics, may help to further enhance the reliability of candidate selection.

Use of ATR-FTIR Spectroscopy and Chemometrics for the Variation of Active Components in Different Harvesting Periods of Lonicera japonica

Lonicera japonica Thunb is a commonly used Chinese herbal medicine, which belongs to the family Caprifoliaceae. The active components varied greatly during bud development. Research on the variation of the main active components is significant for the timely harvesting and quality control of Lonicera japonica. In this study, the attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) combined with the chemometric method was performed to investigate the variability of different harvesting periods of Lonicera japonica. The preliminary characterization from ATR-FTIR fingerprints showed various characteristic absorption peaks of the main active components from the different harvesting times, such as flavonoids, organic acids, iridoids, and volatile oils. Additionally, principal component analysis (PCA) scatter plots showed that there was a clear clustering trend in the samples of the same harvesting period, and the samples of the different harvesting periods could be well distinguished. Finally, further analysis by the orthogonal partial least-squares discriminant analysis (OPLS-DA) showed that there were regular changes in flavonoids, phenolic acids, iridoids, and volatile oils in different harvesting periods. Therefore, ATR-FTIR, as a novel and convenient analytical method, could be applied to evaluate the quality of Lonicera japonica.

Authentication of Herbal Medicines Based on Modern Analytical Technology Combined with Chemometrics Approach: A Review

Since ancient times, herbal medicines (HMs) have been widely popular with consumers as a "natural" drug for health care and disease treatment. With the emergence of problems, such as increasing demand for HMs and shortage of resources, it often occurs the phenomenon of shoddy exceed and mixing the false with the genuine in the market. There is an urgent need to evaluate the quality of HMs to ensure their important role in health care and disease treatment, and to reduce the possibility of threat to human health. Modern analytical technology is can be analyzed for analyzing chemical components of HMs or their preparations. Reflecting complex chemical components' characteristic curves in the analysis sample, and the comprehensive effect of active ingredients of HMs. In this review, modern analytical technology (chromatography, spectroscopy, mass spectrometry), chemometrics methods (unsupervised, supervised) and their advantages, disadvantages, and applicability were introduced and summarized. In addition, the authentication application of modern analytical technology combined with chemometrics methods in four aspects, including origin, processing methods, cultivation methods, and adulteration of HMs have also been discussed and illustrated by a few typical studies. This article offers a general workflow of analytical methods that have been applied for HMs authentication and explains that the accuracy of authentication in favor of the quality assurance of HMs. It was provided reference value for the development and application of modern HMs.

Precise Species Detection in Traditional Herbal Patent Medicine, Qingguo Wan, Using Shotgun Metabarcoding

As one of the high-incidence diseases in the world, pharyngitis seriously affects the lives of those with the condition. Qingguo Wan is a herbal medicine used for treating pharyngitis, and its quality evaluation is currently only accomplished via traditional identification. However, precise identification becomes challenging with fake products on the market or fungal contamination during the production process. This study used the Illumina NovaSeq platform for targeting the ITS2, psbA-trnH, matK, and rbcL sequences to survey the species composition of lab-made and commercial samples. The results showed that a total of 34.56 Gb of raw data that was obtained represented more than 0.23 billion reads. After assembly, annotation, and operational taxonomic unit clustering, 103, 12, 10, and 12 OTUs were obtained, which belonged to the ITS2, psbA-trnH, matK, and rbcL sequences of the mock lab-made and commercial samples. The analytical results indicated that the sequences of all the prescription ingredients were successfully obtained in the two lab-made samples. The positive control medicinal Panax quinquefolius L. sequence was obtained in HSZY175, while Scutellaria baicalensis Georgi, Lonicera japonica Thunb. Menispermum dauricum DC. and Paeonia lactiflora Pall. were detected in the three commercial samples. The detection results of the other four herbs in different fragments were not all the same. In addition, a total of 28 fungi OTUs, representing 19 families and 20 genera, were obtained from both the commercial and mock lab-made samples. Aspergillus, Cladosporium, and Penicillium dominated among the 20 genera. This study demonstrated that the shotgun metabarcoding method is a powerful tool for the molecular identification of the biological ingredients in Qingguo Wan. It can be used to effectively supplement traditional methods while providing a new technique for the quality evaluation of Qingguo Wan.

Anti-inflammatory property and functional substances of Lonicerae Japonicae Caulis

ETHNOPHARMACOLOGICAL RELEVANCE

Lonicerae Japonicae Caulis, the dried stem and branch of Lonicera japonica Thunb., is a Chinese Materia Medica known as Ren Dong Teng in Chinese with long use history in the traditional Chinese medicine (TCM) prescriptions. Lonicerae Japonicae Caulis possesses heat-clearing and detoxifying functions according to the TCM theory. In recent years, a large amount of experimental and clinical studies proved good anti-inflammatory effects of some heat-clearing and detoxifying herbs. The present study aims to reveal the anti-inflammatory property and functional substances of Lonicerae Japonicae Caulis.

MATERIALS AND METHODS

For anti-inflammatory activity test, LPS-induced RAW 264.7 macrophages, DSS-induced SPF male C57BL/6J mice model, and LPS-induced SPF male ICR mice model were used in vitro and in vivo, respectively. The behavioral changes, organ damage, and the expression of inflammatory factors such as TNT-α and IL-6 mRNA expression were measured for activity evaluation. Lonicerae Japonicae Caulis samples were prepared by solvent extraction and subsequent column chromatography. The main components were identified and determined using UPLC-UV analysis as well as NMR interpretation after purification. To testify the contribution of main components for the anti-inflammatory activity, different samples were also prepared by compound-knockout strategy.

RESULTS

Ethanol extract of Lonicerae Japonicae Caulis could attenuate sickness symptoms in mice such as diarrhea, less activity, and depression. It could also alleviate multiple organ damage, and significantly inhibit the expression of pro-inflammatory factors such as TNF-α, IL-1β, IL-6 and IFN-γ in mice. Furthermore, the isochlorogenic acid-rich and biflavonoid-rich fractions and isochlorogenic acids A and C, and ochnaflavone could significantly down-regulate the mRNA expression of TNF-α and IL-6 in LPS-induced RAW 264.7 macrophages.

CONCLUSIONS

Lonicerae Japonicae Caulis possesses anti-inflammatory property. Its isochlorogenic acid-rich and biflavonoid-rich fractions do the major contribution. And their main components, isochlorogenic acids A and C, and ochnaflavone, take main responsibility for the anti-inflammatory property.

The thromboprotective effect of traditional Chinese medicine Tongji 2 granules is dependent on anti-inflammatory activity by suppression of NF-κB pathways

Inflammation is a vital physiological response of the immune system meant to protect against the invasion of pathogens. However, accumulating evidence describes an intimate link between inflammation and thrombosis and cellular elements of the immune system of the immune system such as neutrophils and monocytes/macrophages are emerging as key players in the generation of a prothrombotic milieu suggesting that anti-inflammatory therapy may have a role in the management of thrombosis that is driven by inflammation. Tongji 2 (TJ2) is a traditional Chinese medication manufactured as granules by Tongji hospital of Tongji University (Shanghai, China) with known anti-inflammatory properties. In this study, we examine the effects of TJ2 on inflammation and thrombosis. Our study shows that TJ2 modulates NF-κB activation and thus generates a prominent anti-inflammatory effect. Further, we use mouse models of thrombosis to demonstrate that TJ2 has a beneficial effect in both arterial and venous thrombosis that occurs in the absence of alterations in platelet activation or coagulation.

Deciphering bioactive compounds of complex natural products by tandem mass spectral molecular networking combined with an aggregation-induced emission based probe

Natural products are great treasure troves for the discovery of bioactive components. Current bioassay guided fractionation for identification of bioactive components is time- and workload-consuming. In this study, we proposed a robust and convenient strategy for deciphering the bioactive profile of natural products by mass spectral molecular networking combined with rapid bioassay. As a proof-of-concept, the strategy was applied to identify angiotensin converting enzyme (ACE) inhibitors of Fangjihuangqi decoction (FJHQD), a traditional medicine clinically used for the treatment of heart failure. The chemical profile of FJHQD was comprehensively revealed with the assistance of tandem mass spectral molecular networking, and a total of 165 compounds were identified. With characterized constituents, potential clinical applications of FJHQD were predicted by Bioinformatics Analysis Tool for Molecular mechANism of Traditional Chinese Medicine, and a range of cardiovascular related diseases were significantly enriched. ACE inhibitory activities of FJHQD and its constituents were then investigated with an aggregation-induced emission based fluorescent probe. FJHQD exhibited excellent ACE inhibitory effects, and a bioactive molecular network was established to elucidate the ACE inhibitory profile of constituents in FJHQD. This bioactive molecular network provided a panoramic view of FJHQD's ACE inhibitory activities, which demonstrated that flavones from Astragali Radix and Glycyrrhizae Radix et Rhizoma, saponins from Astragali Radix, and sesquiterpenoids from Atractylodis Macrocephalae Rhizoma were principal components responsible for this effect of FJHQD. Among them, four novel ACE inhibitors were the first to be reported. Our study indicated that the proposed strategy offers a useful approach to uncover the bioactive profile of traditional medicines and provides a pragmatic workflow for exploring bioactive components.

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A novel strategy for deciphering the bioactive profile of traditional medicines was proposed.

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The chemical profile of FJHQD was revealed with assist of tandem mass spectral molecular networking.

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Four new angiotensin converting enzyme inhibitors were discovered.

Applications of Fourier transform infrared spectroscopy to pharmaceutical preparations

Introduction: Various pharmaceutical preparations are widely used for clinical treatment. Elucidation of the mechanisms of drug release and evaluation of drug efficacy in biological samples are important in drug design and drug quality control.Areas covered: This review classifies recent applications of Fourier transform infrared (FTIR) spectroscopy in the field of medicine to comprehend drug release and diffusion. Drug release is affected by many factors of preparations, such as drug delivery system and microstructure polymorphism. The applications of FTIR imaging and nano-FTIR technique in biological samples lay a foundation for studying drug mechanism in vivo.Expert opinion: FTIR spectroscopy meets the research needs on preparations to understand the processes and mechanisms underlying drug release. The combination of attenuated total reflectance-FTIR imaging and nano-FTIR accompanied by chemometrics is a potent tool to overcome the deficiency of conventional infrared detection. FTIR shows an enormous potential in drug characterization, drug quality control, and bio-sample detection.

Characterization, crystal structure and cytotoxic activity of a rare iridoid glycoside from Lonicera saccata

A new iridoid glycoside, methyl (3R,4R,4aS,7S,7aR)-3-hydroxy-7-methyl-5-oxooctahydrocyclopenta[c]pyran-4-carboxylate-3-O-β-D-(1'S,2'R,3'S,4'S,5'R)-glucopyranoside, named loniceroside A, C₁₇H₂₆O₁₀, (1), was obtained from the aerial parts of Lonicera saccata. Its structure was established based on an analysis of spectroscopic data, including 1D NMR, 2D NMR and HRESIMS, and the configurations of the chiral C atoms were determined by X-ray crystallographic analysis. The single-crystal structure reveals that the cyclopenta[c]pyran scaffold is formed from a five-membered ring and a chair-like six-membered ring connected through two bridgehead chiral C atoms. In the solid state, the glucose group of (1) plays an important role in constructing an unusual supramolecular motif. The structure analysis revealed adjacent molecules linked together through intermolecular O-H...O hydrogen bonds to generate a banded structure. Furthermore, the banded structures are linked into a three-dimensional network by interesting hydrogen bonds. Biogenetically, compound (1) carries a glucopyranosyloxy moiety at the C-3 position, representing a rare structural feature for naturally occurring iridoid glycosides. The growth inhibitory effects against human cervical carcinoma cells (Hela), human lung adenocarcinoma cells (A549), human acute mononuclear granulocyte leukaemia (THP-1) and the human liver hepatocellular carcinoma cell line (HepG2) were evaluated by the MTT method.

Apparent penetration depth in attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy of Allium cepa L. epidermis and cuticle

Over the past decades, ATR-FTIR has emerged as promising tool for the identification of plants at the genus and (sub-) species level through surface measurements of intact leaves. Theoretical considerations regarding the penetration depth of the evanescent wave into the sample and the thickness of plant leaf cuticles suggest that the structure and composition of the cuticle represent universal taxonomic markers. However, experimental evidence for this hypothesis is scarce. In the current contribution, we present results of a series of simple experiments on epidermal monolayers derived from the bulbs of Allium cepa L. (Amaryllidaceae) as a model system to study the effect of an IR active probe located beyond the theoretical penetration depth of the evanescent wave. We found that this probe had a significant influence on the ATR-FTIR spectra for up to 4 epidermal layers stacked on top of each other corresponding to a total thickness of around 60 μm, exceeding the theoretical penetration depth of the evanescent wave by a factor of around 20. Altogether, our data indicate a major discrepancy between theory and practice in ATR-FTIR spectroscopy in general and provide strong evidence that in general plant leaf spectra cannot be fully explained by the structure and composition of the cuticle alone.

Simultaneous determination of seven flavonoids, two phenolic acids and two cholesterines in Tanreqing injection by UHPLC-MS/MS

A new ultra-high performance liquid chromatography combined with triple quadrupole mass spectrometry was developed to evaluate the quality of Tanreqing injection. Seven flavonoids (Rutin, Baicalin, Scutellarin, Chrysin-7-O-Beta-d-glucoronide, Oroxylin A-7-O-β-d-glucoronide, Wogonin, Luteolin-7-O-glucoside), two phenolic acids (Chlorogenic acid, Caffeic acid) and two cholesterines (Ursodeoxycholic acid, Chenodeoxycholic acid) in Tanreqing injection could be measured simultaneously. For the determination of the eleven compounds, the conditions were set as follows: The mobile phase was a gradient of 0.1% aqueous formic acid solution (A) and acetonitrile (B); the flow rate was 0.2 mL min^-1, the column was Acquity UPLC HSS T3 column (2.1 mm × 100 mm, 1.8 μm); and the multiple-reaction monitoring (MRM) with a negative electro spray ionization interface (ESI-) was selected. Within the test ranges, all the standard regression curves showed excellent linear regression (r > 0.99). In terms of (relative standard deviation) RSDs, the precision, repeatability and stability of the eleven compounds were all lower than 3%. The recovery rates of Tanreqing injection and the RSD were 97.8-103.7% and 0.4%-2.0%, respectively. The RSD value was in accordance with the requirements of less than 3.0%. This method has been successfully used in the analysis of Tanreqing injection. In summary, a fast, accurate and reliable UPLC-ESI^--MS/MS method was successfully developed for the simultaneous detection of the eleven major active ingredients with different chemical structures in Tanreqing injection, and can be used for the quality control of Tanreqing injection as well.