Phytochemical and pharmacological progress on the genus Syringa

Comparative Component Composition of Flowers in Several Syringa Species (Oleaceae)

Because insufficient relevant data are available, the component composition of flowers was studied comparatively in six lilac species of the genus Syringa L. (Oleaceae): S. emodi Wall., S. josikaea Jacg., S. komarowii Schneid., S. reticulata (Blume) H. Hara ssp. amurensis (Rupr.) P. S. Green et M. C. Chang, S. sweginzowii Koehne et Lingelsh, and S. vulgaris L. Plants were from the collection of the South Ural Botanical Garden-Institute. Contents were established for major groups of biologically active substances (BASs): flavonoids, hydroxycinnamic acids, tannins, and organic acids. The highest contents of all BAS groups were observed in S. komarowii flowers: flavonoids, 4.25 ± 0.21%; hydroxycinnamic acids, 6.13 ± 0.29%; tannins, 9.3 ± 0.5%; ascorbic acid, 0.468 ± 0.022%; and organic acids, 10.7 ± 0.5%. The contents were somewhat lower in S. emodi and S. sweginzowii and minimum in S. josikaea. Comparisons of the qualitative and quantitative BAS profiles showed that certain Syringa species cultivated in the Republic of Bashkortostan are promising to further study in terms of their possible use in scientific medicine and the development of herbal remedies.

Phenolic Compounds and Organic Acid Composition of Syringa vulgaris L. Flowers and Infusions

The study aimed to determine the content of phenolic compounds (phenolic acids and flavonoids) and organic acids in dried flowers and water infusions of non-oxidised and oxidised flowers from four lilac cultivars. The diversity in the total phenolic and flavonoid content was in the flowers (18.35-67.14 and 2.03-2.65 mg g^-1 DW, respectively) and infusions (14.72-47.78 and 0.20-1.84 mg per 100 mL infusion, respectively) depending the flower colour and form (oxidised and non-oxidised). Phenolic compounds and organic acids were susceptible to oxidation. Compared to infusions, flowers had more phenolic compounds and organic acids. The highest content of most phenolic compounds was confirmed for non-oxidised purple flowers (up to 7825.9 µg g^-1 DW for chlorogenic acid) while in infusions for non-oxidised white flowers (up to 667.1 µg per 100 mL infusions for vanillic acid). The phenolic profile of the infusions was less diverse than that of flowers. The scavenging ability ranged from 52 to 87%. The highest organic acid content in flowers was for oxidised blue and purple flowers (2528.1 and 2479.0 µg g^-1 DW, respectively) while in infusions the highest organic acid content was for oxidised purple flowers (550.1 µg per 100 mL infusions).

Alashanines A-C, Three Quinone-Terpenoid Alkaloids from Syringa pinnatifolia with Cytotoxic Potential by Activation of ERK

Three quinone-terpenoid alkaloids, alashanines A-C (1-3), possessing an unprecedented 6/6/6 tricyclic conjugated backbone and quinone-quinoline-fused characteristic, were isolated from the peeled stems of Syringa pinnatifolia. Their structures were elucidated by analysis of extensive spectroscopic data and quantum chemical calculations. A hypothesis of biosynthesis pathways for 1-3 was proposed on the basis of the potential precursor iridoid and benzoquinone. Compound 1 exhibited antibacterial activities against Bacillus subtilis and cytotoxicity against HepG2 and MCF-7 human cancer cell lines. The results of the cytotoxic mechanism revealed that compound 1 induced apoptosis of HepG2 cells through activation of ERK.

The Ethanol Extract of Syringa oblata Heartwood, a Mongolian Folk Medicine Containing Major Lignans, Exerts Analgesic and Sedative Effects on Mice

The heartwood of Syringa oblata Lindl. (SO) is one of Mongolian folk medicines to treat insomnia and pain, while its pharmacological evaluation and underlying mechanism remain unclear. In this study, the sedative effect of ethanol extract of SO (ESO) was evaluated with the locomotor activity test and the threshold dose of pentobarbital sodium-induced sleep test in mice, and the hot plate test, acetic acid-induced writhing test, and formalin test in mice were used to evaluate its analgesic effect. The underlying mechanism of ESO analgesia was explored by RT-PCR and western blot analysis, which is associated with the regulation of the NF-κB signaling pathway. Besides, the main constituents of ESO were characterized by LC/MS data analysis and comparison with isolated pure compounds. The current findings brought evidence for clinical application and further pharmacological and phytochemical studies on SO.

Establishment of fingerprint and mechanism of anti-myocardial ischemic effect of Syringa pinnatifolia

OBJECTIVE

To establish the fingerprint of Syringa pinnatifolia Hemsl. (SP), analyze the blood components of SP, and explore the possible mechanism of SP's anti-myocardial ischemia, so as to provide scientific basis for the follow-up development and research of SP and lay a foundation for its clinical application.

METHODS

The fingerprint of SP was established by UPLC-QE-MS and GC-MS. A rat Myocardial infarction (MI) was constructed by ligating the left anterior descending branch (LAD) of the rat coronary artery, and SP alcohol extract was administered to evaluate its anti-myocardial ischemic effect. We analyzed the blood components of SP, screened the active compounds, established a database of SP anti-myocardial ischemic targets, and explored the possible mechanism of SP in treating MI by bioinformatics. The rats were examined by echocardiography, serum biomarkers were determined, and pathological changes were observed by histopathological examination. TUNEL staining was performed to detect the apoptotic level of cells, and western blot and qRT-PCR were performed to detect the expression levels of Bcl-2, Bax and caspase-3 in heart tissues.

RESULTS

In the fingerprint of SP, 24 common peaks were established, and the similarity evaluation results of 10 batches of SP were all > 0.9. UPLC-QE-MS and GC-MS detected a total of 17 active ingredients in the drug-containing serum, including terpenoids, flavonoids, phenols, phenylpropanoids and phenolic acids, the most abundant of which was resveratrol. Enrichment analysis of SP targets against myocardial ischemia revealed that key candidate targets of SP were significantly enriched in multiple pathways associated with apoptosis. Resveratrol was administered to the successfully modeled rats, and the results showed that the resveratrol group significantly reduced LVEDd and LVEDs and significantly increased EF and FS in all groups compared with the model group. Resveratrol significantly reduced the levels of CK-MB and LDH in serum compared to the model group (p < 0.001). Hematoxylin-eosin (HE) staining of rat myocardial tissue showed that all lesions were reduced under microscopic observation in the resveratrol group compared with the model group. RT-PCR and western blot results showed that resveratrol group down-regulated the expression of the pro-apoptotic factor Bax, up-regulated the expression of the anti-apoptotic factor Bcl-2, and decreased the expression of Caspase-3.

CONCLUSION

The established fingerprints are accurate, reliable and reproducible, and can be used as an effective method for the quality control of the herbs. The anti-myocardial ischemia effect of SP may be that resveratrol can improve cardiac function and inhibit cardiomyocyte apoptosis to protect cardiomyocytes. The present study provides ample evidence for the clinical use of SP, suggesting that this drug has great potential in the treatment of ischemic heart disease.

Phytochemical and pharmacological progress on Syringa oblata, a traditional Mongolian medicine

Syringa oblata is a traditional Mongolian medicine mainly distributed in the Helan Mountains (the boundaries of Inner Mongolia and Ningxia, China) and the north of Yan Mountains (Aohan Qi, Inner Mongolia, China). It is clinically used to treat diseases caused by Heyi, such as heartache and heat pathogen in the heart. Phytochemical studies on S. oblata revealed the presence of iridoids, lignans, triterpenes, phenylpropanoids, phenylethanoids, and volatile components. Pharmacological investigations revealed a broad spectrum of bioactivities, such as antimicrobial, antioxidant, antiproliferative, and hepatoprotective effects. This article summarized the chemical components and pharmacological activities of S. oblata, providing a scientific rationale for its bioactive constituents, quality control, and utilization as an important medicine.

Syringenes M - Q, Eremophilane Sesquiterpenoid Dimers from the Peeled Stems of Syringa pinnatifolia

As a part of systematic studies on Syringa pinnatifolia, a continued phytochemical investigation guided by ¹ H-NMR and LC/MS data on the ethanol extract afforded five new dimeric eremophilane sesquiterpenoids, namely syringenes M-Q (1-5). These structures were elucidated by extensive analysis of spectroscopic data, including infrared (IR), high-resolution electrospray ionization mass spectrometry (HR-ESI-MS), nuclear magnetic resonance (NMR), quantum-mechanics-based computational analysis of NMR chemical shifts, and single-crystal X-ray diffraction. Compounds 4 and 5 showed inhibitory activities against NO production induced by lipopolysaccharide in RAW264.7 macrophage cells, with IC₅₀ values of 5.1 and 9.3 μM, compared to positive control indomethacin (IC₅₀ 33.6 μM). These dimeric eremophilane sesquiterpenoids may be potential markers for discriminating this species from the genus Syringa and the Oleaceae family.

Identification of a new strain of ligustrum virus A causing leaf necrosis and chlorosis symptoms in Syringa oblata var. dilatata (Nakai) Rehder

In 2020, lilac trees showing virus-like symptoms such as leaf necrosis and chlorosis were observed in Korea. After RT-PCR detection with specific primer sets designed based on previously reported nucleotide sequences of viruses in lilac, the agent was identified as ligustrum virus A (LVA). The complete genome of the virus was sequenced and used for phylogenetic analysis. The genome of this novel strain of LVA, LVA-SNU, is 8524 nucleotides long, excluding the poly(A) tail, and shares the highest nucleotide sequence identity (77.28%) with LVA-Sob, which was detected in a plant of the same species, Syringa oblata, in China, whereas LVA-Sob shares higher sequence identity (97.89%) with LVA-SK, which has been detected in host plants of various species.

Syringa microphylla Diels: A comprehensive review of its phytochemical, pharmacological, pharmacokinetic, and toxicological characteristics and an investigation into its potential health benefits

BACKGROUND

Syringa microphylla Diels is a plant in the family Syringa Linn. For hundreds of years, its flowers and leaves have been used as a folk medicine for the treatment of cough, inflammation, colds, sore throat, acute hepatitis, chronic hepatitis, early liver cirrhosis, fatty liver, and oesophageal cancer.

PURPOSE

For the first time, we have comprehensively reviewed information on Syringa microphylla Diels that is not included in the Pharmacopoeia, clarified the pharmacological mechanisms of Syringa microphylla Diels and its active ingredients from a molecular biology perspective, compiled in vivo and in vitro animal experimental data and clinical data, and summarized the toxicology and pharmacokinetics of Syringa microphylla Diels. The progress in toxicology research is expected to provide a theoretical basis for the development of new drugs from Syringa microphylla Diels, a natural source of compounds that are potentially beneficial to human health.

METHODS

The PubMed, Google Scholar, China National Knowledge Infrastructure, Web of Science, SciFinder Scholar and Thomson Reuters databases were utilized to conduct a comprehensive search of published literature as of July 2021 to find original literature related to Syringa microphylla Diels and its active ingredients.

RESULTS

To date, 72 compounds have been isolated and identified from Syringa microphylla Diels, and oleuropein, verbascoside, isoacteoside, echinacoside, forsythoside B, and eleutheroside B are the main active components. These compounds have antioxidant, antibacterial, anti-inflammatory, and neuroprotective effects, and their safety and effectiveness have been demonstrated in long-term traditional applications. Molecular pharmacology experiments have indicated that the active ingredients of Syringa microphylla Diels exert their pharmacological effects in various ways, primarily by reducing oxidative stress damage via Nrf2/ARE pathway regulation, regulating inflammatory factors and inducing apoptosis through the MAPK and NF-κB pathways.

CONCLUSION

This comprehensive review of Syringa microphylla Diels provides new insights into the correlations among molecular mechanisms, the importance of toxicology and pharmacokinetics, and potential ways to address the limitations of current research. As Syringa microphylla Diels is a natural low-toxicity botanical medicine, it is worthy of development and utilization and is an excellent choice for treating various diseases.

Efficacy of Different Concentrations of NAA on Selected Ornamental Woody Shrubs Cuttings

Ornamental woody shrubs are used in landscape design worldwide. Their propagation can be made generatively and vegetatively. Vegetative propagation methods are mostly used by nurseries, as such methods are quick and the newly propagated plants inherit the genetics of the mother plant. However, rooting in some woody plants is slow and, unfortunately, sometimes produces only a small number of rooted cuttings. In this study, shoot cuttings from six selected ornamental woody shrubs were subjected to different concentrations of rooting stimulators (0.5 (NAA5) and 0.8 (NAA8) % concentrations of 1-Naphthylacetic acid; cuttings without treatment were considered as control) and propagated in two different periods (spring and summer). Our results show that significant changes were obtained in the plants under the different treatments. Most of the plants showed a positive response to both treatments, expect for Cotinus coggygria ‘Royal Purple’, which, compared to control, registered decreases in all the tested parameters under NAA5 treatment. Ilex aquifolium was the species that showed increments in all the parameters when NAA treatments were applied. In conclusion, our research suggests that NAA increases rooting in ornamental woody shrubs, although in some cases rooting could be a species-dependent process.

Four new secoiridoids from the stem barks of Syringa reticulata (Bl.) Hara

Four new secoiridoids, syrretoside A (1), syrretoside B (2), 5β, 8β-syrretaglucone C(3), 5β, 8α-syrretaglucone C (4), together with eight known secoiridoids (5-12), were isolated from the stem barks of Syringa reticulata (Bl.) Hara. The structures of isolated compounds were established based on the physical and chemical means, NMR spectroscopy, high-resolution mass spectrometry (HR-ESI-MS), and circular dichroism spectrum (CD), as well as in comparison with the literature. The cytotoxicity of isolated compounds was investigated using CCK8 assay, which showed that these compounds had different degrees of inhibitory effect on two human tumor (MGC803, LN229) cell lines.

Chemical Profile, Cytotoxic Activity and Oxidative Stress Reduction of Different Syringa vulgaris L. Extracts

Syringa vulgaris L. (common lilac) is one of the most popular ornamental species, but also a promising not comprehensively studied source of bioactive compounds with important therapeutic potential. Our study was designed to characterize the chemical composition and to assess the antioxidant and cytotoxic properties of ethanolic extracts obtained from S. vulgaris L. flowers, leaves, bark, and fruit. The chemical profile of the ethanolic extracts was investigated using chromatographic (HPLC-DAD-ESI⁺, GC-MS) and spectral (UV-Vis, FT-IR) methods, while the protective effect against free radicals was evaluated in vitro by different chemical assays (DPPH, FRAP, CUPRAC). The cytotoxic activity was tested on two tumoral cell lines, HeLa, B16F10, using the MTT assay. Significant amounts of free or glycosylated chemical components belonging to various therapeutically important structural classes, such as phenyl-propanoids (syringin, acteoside, echinacoside), flavonoids (quercetin, kaempferol derivatives) and secoiridoids (secologanoside, oleuropein, 10-hydroxy oleuropein, demethyloleuropein, syringalactone A, nuzhenide, lingstroside) were obtained for the flowers, leaves and bark extracts, respectively. Furthermore, MTT tests pointed out a significant cytotoxic potential expressed in a non-dose-dependent manner toward the tumoral lines. The performed methods underlined that S. vulgaris extracts, in particular belonging to flowers and leaves, represent valuable sources of compounds with antioxidant and antitumoral potential.

Traditional uses, phytochemistry and pharmacology of genus Syringa: A comprehensive review

ETHNOPHARMACOLOGICAL RELEVANCE

Genus Syringa, which belongs to Oleaceae family, contains 21 accepted species mainly distributed in Southeast Europe, Japan, China, Himalayas, etc. The various parts of Syringa species have been used as traditional Chinese herbal medicines for treatment of cough, myocardial ischemia, acute icteric hepatitis, diarrhea, conjunctivitis, bronchitis and other ailments.

AIM OF THE STUDY

A more comprehensive and in-depth review about the phytochemistry, pharmacology, traditional medicinal uses and clinical applications as well as toxicology of Syringa have summarized and hope to provide a relatively novel angle for further clinical applicantion on genus.

MATERIALS AND METHODS

The literatures about Syringa were collected via a series of scientific search engines including Web of Science, PubMed, Elsevier, Google Scholar, SciFinder and CNKI.

RESULTS

The phytochemical studies revealed that about 302 compounds include phenylpropanoids, iridoids, phenylethanols, flavonoids, triterpenes and other minor compounds have been isolated and identified from Syringa species. Phenylpropanoids and iridoids are the main constituents among these compounds and may be responsible for the activities directly or indirectly. As traditional medicine, Syringa applied to treat cough, diarrhea, acute icteric hepatitis, vomit, abdominal pain, bronchitis and other ailments. Most of traditional uses are related the biological activities and confirmed by modern studies. Pharmacological researches in vitro and in vivo revealed that the extracts and pure compounds possessed significantly hepatoprotective, anti-inflammatory, antimicrobial, antioxidant, antitumor, antiviral, cardioprotective, immunomodulatory and other activities.

CONCLUSIONS

The phytochemistry, pharmacology, traditional uses and clinical applications described in this article demonstrated that Syringa species possessed a huge number of activities and these findings will promote the further action mechanisms studies. However, fewer preclinical and clinical studies are focued on the pharmacokinetics of crudes extracts and conpounds from Syringa. The explored of new agents with Syringa species as ingredients may be limited. It points to the further in-depth investigations on pharmacokinetics as well as toxicological are essential in future for assessment the effectiveness and safety of drug.

Syringoleosides A-H, Secoiridoids from Syringa dilatata Flowers and Their Inhibition of NO Production in LPS-Induced RAW 264.7 Cells

Repeated column chromatography of Syringa dilatata flowers, a native shrub to Korea, led to the isolation of eight new oleoside-type secoiridoids, syringoleosides A-H (1-8), as well as five known secoiridoids (9-13). The new chemical structures were identified through spectroscopic data analysis, as well as the application of chemical methods. Compounds 1, 2, 6, 7, 11, and 13 showed suppression effects on NO production in LPS-induced RAW 264.7 cells, with IC₅₀ values ranging from 32.5 ± 9.8 to 65.7 ± 11.0 μM, and no visible toxicity. The content of the major secoiridoids in S. dilatata flowers, compounds 1, 4, 5, 8, 9, 12, and 13, were determined through HPLC analysis.

Syringa pinnatifolia Hemsl. fraction protects against myocardial ischemic injury by targeting the p53-mediated apoptosis pathway

BACKGROUND

Peeled stems of Syringa pinnatifolia Hemsl. (SP) have been widely used to treat extra "He-Yi" induced myocardial ischemia for hundreds of years in Inner Mongolia, China and previous result showed that intragastric pretreatment with total extract (T) of SP has a protective effect against myocardial infarction (MI).

HYPOTHESIS

This study aims to describe the pharmacological investigation and chemical characterization of the major (M) and minor (N) fractions obtained from T through column chromatography fractionation on macroporous resin and to explore whether the regulatory effects were linked to the p53-mediated apoptosis pathways.

STUDY DESIGN

Left anterior descending (LAD) coronary artery-ligated mice and H9c2 cells cultured in serum-free medium under hypoxic conditions were treated with T, M, and N.

METHODS

Echocardiography was performed and biomarkers in serum were determined in mice, and pathological changes were observed through histopathology assay. Immunofluorescence staining and qRT-PCR were used to detect the expression levels of p53 in heart tissue. Flow cytometry was used to measure the level of apoptosis and caspase-3 activity in H9c2 cells. Western blot analysis was conducted to detect p53 and p53-mediated proteins apoptosis pathways of in both tissue and H9c2 cells.

RESULTS

Both T and M have an equivalent cardioprotective effect whereas N is non-active. M decreased MI-induced myocardial compensatory expansion by decrease of left ventricular end-systolic diameter (LVESd) and left ventricular end-diastolic diameter (LVEDd) and prevented decreases in ejection fraction (EF) and fractional shortening (FS). The MI-induced increased levels of creatine kinase-MB (CK-MB), lactate dehydrogenase (LDH), and hypersensitive C-reactive protein (hs-CRP) were decreased and the expanded infarction size was reduced. M could also improve cell viability and inhibit apoptosis in H9c2 cells under hypoxic conditions. Immunofluorescence and qRT-PCR assay showed that M suppressed p53 expression in the myocardium. Western blot analysis showed that M could prevent MI-induced activation of p53-mediated apoptosis pathway in both myocardium and H9c2 cells.

CONCLUSION

The results demonstrated that M may protect against myocardial ischemia by improving cardiac function and inhibiting cardiomyocytes apoptosis. Overall, the present findings supported the clinical application of SP and enriched the research of anti-myocardial ischemia drug from traditional medicines.

Bioactive Sesquiterpenoids from the Peeled Stems of Syringa pinnatifolia

Fourteen new sesquiterpenoids, alashanoids A-H (1, 2, and 4-9), (+)-2,9-humuladien-6-ol-8-one (3b), and five pairs of enantiomers (1 and 4-7), along with eight known analogues (3a and 10-16) were isolated from the stems of Syringa pinnatifolia. The structures were established using IR, UV, MS, and NMR data. The absolute configurations of the new compounds were resolved by X-ray diffraction, a modification of Mosher's method, and experimental and calculated ECD data analysis. The new sesquiterpenoids represent three skeletons: a rare 2,2,5,9-tetramethylbicyclo[6.3.0]-undecane (1), a humulane-type (2-8), and a caryophyllene-type (9) skeleton. Compounds 6a, 7, and 11 showed protective effects against hypoxia-induced injury to H9c2 cells at a concentration of 40 μM, and 5-7, 11, and 13 inhibited NO production in LPS-induced RAW264.7 macrophage cells with IC₅₀ values ranging from 13.6 to 70.6 μM. These compounds decreased the TNF-α and IL-6 levels in RAW264.7 cells in a concentration-dependent manner at 20-80 μM.

Spectrum-Effect Relationships Between the Bioactive Ingredient of Syringa oblata Lindl. Leaves and Its Role in Inhibiting the Biofilm Formation of Streptococcus suis

Syringa oblata Lindl. (S. oblata) has been used in herbal medicines for treating bacterial diseases. It is also thought to inhibit Streptococcus suis (S. suis) biofilm formation. However, due to the inherent nature of the complexity in its chemical properties, it is difficult to understand the possible bioactive ingredients of S. oblata. The spectrum-effect relationships method was applied to screen the main active ingredients in S. oblata obtained from Heilongjiang Province based on gray relational analysis. The results revealed that Sub-MICs obtained from 10 batches of S. oblata could inhibit biofilm formation by S. suis. Gray relational analysis revealed variations in the contents of 15 main peaks and rutin was discovered to be the main active ingredient. Then, the function of rutin was further verified by inhibiting S. suis biofilm formation using crystal violet staining. Computational studies revealed that rutin may target the chloramphenicol acetyltransferase protein in the biofilm formation of S. suis. In conclusion, this study revealed that the spectrum-effect relationships and computational studies are useful tools to associate the active ingredient with the potential anti-biofilm effects of S. oblata. Here, our findings would provide foundation for the further understanding of the mechanism of S. oblata intervention in biofilm formation.

Effects of Phytochemically Characterized Extracts From Syringa vulgaris and Isolated Secoiridoids on Mediators of Inflammation in a Human Neutrophil Model

Aim of the study: The aim of the present study was to investigate the effects of phytochemically characterized extracts connected with the traditional use (infusions and ethanolic extracts) of different parts of Syringa vulgaris (common lilac) on the pro-inflammatory functions of neutrophils. Active compounds were isolated from the most promising extract(s) using bioassay-guided fractionation, and their activity and molecular mechanisms of action were determined.

Methods: The extracts were characterized using a HPLC-DAD- MSⁿ method. The effects on ROS, MMP-9, TNF-α, IL-8, and MCP-1 production by neutrophils were measured using luminol-dependent chemiluminescence and enzyme-linked immunosorbent assay (ELISA) methods. The effects on p38MAPK, ERK1/2, JNK phosphorylation, and NF-kB p65 translocation were determined using western blots.

Results: The major compounds detected in the extracts and infusions belong to structural groups, including caffeic acid derivatives, flavonoids, and iridoids. All extracts and infusions were able to significantly reduce ROS and IL-8 production. Bioassay-guided fractionation led to the isolation of the following secoiridoids: 2″-epiframeroside, oleonuezhenide, oleuropein, ligstroside, neooleuropein, hydroxyframoside, and framoside. Neooleuropein appeared to be the most active compound in the inhibition of cytokine production by attenuating the MAP kinase pathways.

Conclusion: The present study demonstrated that common lilac, which is a traditionally used medicinal plant in Europe, is a valuable source of active compounds, especially neooleuropein.

Phenolic composition, antioxidant and antinociceptive activities of Syringa vulgaris L. bark and leaf extracts

Metabolite profile, antioxidant and antinociceptive activities of Syringa vulgaris bark and leaf methanolic extracts were investigated. By means of HPLC-DAD-ESI-TOF and HPLC-DAD-ESI-MS/MS, a total of 33 phenolics were identified, including 15 secoiridoids, 6 phenylpropanoids, 3 flavonoids, 3 lignans and 6 low molecular weight phenols. Validated quantitative analysis show that syringin (2.52%) and rutin (1.13%) are the main phenolic compounds in bark and leaf, respectively. Notable radical scavenging and antinociceptive activities of the bark and leaf extracts were confirmed by in vitro DPPH^● and ABTS^●+ assays and by in vivo hot-plate method in mice, respectively. Our results could lay the scientific basic of future clinical perspectives of lilac bark and leaf.

Hydroxycinnamoyl derivatives and secoiridoid glycoside derivatives from Syringa vulgaris flowers and their effects on the pro-inflammatory responses of human neutrophils

Thirteen new compounds including caffeoyl-glucaric and p-coumaroyl-altraric acid derivatives, one monoterpenoid glucoside, four secoiridoid glycosides, and three hydroxycinnamoyl phenylpropanoid glycosides esterified with an oleoside 11-methyl ester along with fifteen known compounds were isolated from flowers of Syringa vulgaris L. (Oleaceae). Their structures were elucidated by high-resolution spectroscopic methods. The tested compounds were able to decrease the production of reactive oxygen species. Moreover, oleoechinacoside (13), demethylhydroxyoleonuezhenide (14), demethyloleonuezhenide (15), syringaoleoacteoside (25) and oleoacteoside (26) at the concentration of 50μM, moderately suppressed the LPS-stimulated release of pro-inflammatory chemokine IL-8 and TNF-α from human neutrophils. Moreover, oleonuezhenide (12), oleoside 11-methyl ester (16) and oleoacteoside (26) at the concentration of 50μM were able to induce the surface expression of interleukin 10 receptor, which is suppressed by the incubation of monocyte/macrophage cells with LPS.

Noralashinol B, a norlignan with cytotoxicity from stem barks of Syringa pinnatifolia

One new norlignan, noralashinol B (1), and one new natural product, proposed noralashinol C (2), were isolated in a continuous phytochemical investigation on the stem barks of Syringa pinnatifolia. Their structures were elucidated based on the analysis of spectroscopic data, including mass spectrometry and 1D and 2D NMR spectroscopies, and the absolute configuration was determined by experimental and calculated electronic circular dichroism. Compound 1 showed a weak cytotoxicity against HepG2 hepatic cancer cells with its IC₅₀ value of 31.7 μM. Furthermore, 1 induced apoptosis of HepG2 cells in a dose-dependent manner at concentrations of 0-80.0 μM.

Alashinols F and G, two lignans from stem bark of Syringa pinnatifolia

Two new lignans, alashinols F and G (1 and 2), together with two known analogues (-)-secoisolariciresinol (3) and meso-secoisolariciresinol (4) were isolated from the stem bark of Syringa pinnatifolia, a Mongolian folk medicine with anti-myocardial ischaemic effects. Their structures were elucidated on basis of spectroscopic data analyses, including MS and 1D and 2D NMR, and their absolute configurations were elucidated on the basis of experimental and calculated electronic circular dichroisms. The in vitro anti-inflammation and anti-hypoxia evaluations were also discussed.

Extract of Syringa oblata: A new biocontrol agent against tobacco bacterial wilt caused by Ralstonia solanacearum

Ralstonia solanacearum causes serious wilt disease in tobacco. To effectively control this disease, the antibacterial activity of 95% ethanol extracts from the flower buds of Syringa oblata was examined. Based on GC-MS analysis and an inhibition experiment against R. solanacearum, the main antibacterial component is eugenol. We further determined the effect of eugenol on the physiology, biochemistry, and cellular morphology of R. solanacearum. The results showed that eugenol can destroy wilt bacteria, leading to the disappearance of flagella, the leakage of contents, and the appearance of a cavity. SDS-PAGE showed that eugenol decreased protein content in R. solanacearum, reduced medium carbohydrate utilization, and inhibited CAT and SDH activity. The above results showed that eugenol had a significant inhibitory effect on R. solanacearum and this component has the potential to prevent tobacco bacterial wilt.

Anti-myocardial ischemia effect of Syringa pinnatifolia Hemsl. by inhibiting expression of cyclooxygenase-1 and -2 in myocardial tissues of mice

ETHNOPHARMACOLOGICAL RELEVANCE

The peeled stem of Syringa pinnatifolia Hemsl. (SP) is a traditional medicine in Inner Mongolia, China. The powder form of SP has been widely used for hundreds of years to relieve "He-Yi" related myocardial ischemia independently or in a traditional Chinese medicine preparation.

MATERIALS AND METHODS

SP was extracted with 95% and 80% ethanol. Chemical profiling was performed using HPLC-DAD and IT-TOF-ESI-MS analyses. Myocardial ischemia was produced by ligation of the left anterior descending (LAD) coronary artery to evaluate the anti-myocardial ischemia effect of SP. Male C57BL/6 mice were randomly divided into six groups (n=10 per group): a sham group, a model group, groups pretreated with SP at three dosages (20mg/kg, 40mg/kg, and 80mg/kg, intragastrically), and a positive control group (acetylsalicylic acid, ASA, 53mg/kg, intragastrically). Echocardiography was performed to determine heart function by measuring ejection fraction and fractional shortening. The levels of creatine kinase-MB (CK-MB) and lactate dehydrogenase (LDH) in serum, and 6-keto-PGF1α and TXB2 both in plasma and in protein homogenate of myocardial tissue were also measured. The levels of cyclooxygenase (COX)-1 and -2 in the heart tissue and their expressions in mouse myocardial tissue were determined using Western blot and an immunofluorescence assay, respectively. Inflammatory cell infiltration and collagen deposition changes in the myocardial ischemic tissue were observed by pathological examination.

RESULTS

Intragastric pretreatment with SP produced a dose-dependent increase in cardiac function. SP at 80mg/kg significantly improved the EF (p<0.001) and FS (p<0.01) compared with the model group, as well as the levels of serum CK-MB and LDH decreased obviously (p<0.001), approaching those in the sham group. Besides, an obvious reduction in inflammatory cells infiltration and collagen deposition in the infarcted myocardial tissue was shown in each SP treatment group. In addition, SP increased 6-keto-PGF1α and decreased TXB2 levels in the plasma, whereas the opposite pattern was observed in the protein homogenate from the myocardial tissues at the infarction edge, but keeping balance the ratio of 6-keto-PGF1α and TXB2, which is better than ASA in plasma. The mechanisms is associated with the downregulated expressions of COX-1 (p<0.05) and COX-2 (p<0.001).

CONCLUSIONS

Ethanol extract of SP has a protective effect against myocardial ischemia via down regulation of COX-1 and COX-2 expression and by adjusting the ischemia-induced imbalance between 6-keto-PGF1α and TXB2. This study shows substantial evidence to support the clinical application of SP and indicates that such medicine has great potential for treating ischemia-induced heart disease.

The antibacterial activity of syringopicroside, its metabolites and natural analogues from Syringae Folium

In the present study, the in vitro antibacterial activity of an effective fraction (ESF) from Syringae Folium (SF) on Methicillin-resistant Staphylococcus aureus (MRSA) was evaluated and then its in vivo activity was evaluated by using the MRSA-infected mouse peritonitis model. The ESF showed a significant in vitro and in vivo activity on decreasing the Minimum Inhibitory Concentrations (MICs) and increasing the survival rate of mouse from 42.8% to 100%. Six iridoid glucosides (IGs) of ESF were characterized by UPLC-TOF-MS method and also isolated by column chromatography. Most of them showed in vitro anti MRSA activity. Syringopicroside (Sy), the major compound of IGs, was found to increase the survival rate from 42.8% to 92.8% of the MRSA-infected mouse, which revealed Sy is also the main active components of ESF. In order to know why the effect of oral administration of SF is better than its injections in clinic and the metabolites of Sy, seven metabolites of Sy were isolated from rat urine and identified on the basis of NMR and MS spectra. Most of metabolites possessed stronger in vitro anti-MRSA activity than that of Sy, which furtherly proved the clinical result.

Characterization of antioxidant phenolics in Syringa vulgaris L. flowers and fruits by HPLC-DAD-ESI-MS

In this study the polyphenolic composition of lilac flowers and fruits was determined for the first time. For the identification of compounds, accurate molecular masses and formulas, acquired by LC and ESI-TOF-MS and fragmentation pattern given by LC-ESI/MS/MS analyses, were used. Our chromatographic system in conjunction with tandem MS was found to be valuable in the rapid separation and determination of the multiple constituents in methanolic extracts of lilac flowers and fruits. Altogether 34 phenolics, comprising 18 secoiridoids, seven phenylpropanoids, four flavonoids and five low-molecular-weight phenols, were identified. As marker compounds two secoiridoids (oleuropein and nuzhenide), two phenylpropanoids (acteoside and echinacoside) and rutin were quantified by validated methods. As a result of quantitative analysis, it was confirmed that flowers contain significant amounts of phenylpropanoids (acteoside, 2.48%; echinacoside, 0.75%) and oleuropein (0.95%), while in fruits secoiridoid oleuropein (1.09%) and nuzhenide (0.42%) are the major secondary metabolites. The radical scavenging activities of the extracts and the constituents were investigated by DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS [2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid)] assays. Both extracts show remarkable antioxidant activities. Our results clearly show that lilac flowers and fruits are inexpensive, readily available natural sources of phenolic compounds with pharmacological and cosmetic applications. Copyright © 2015 John Wiley & Sons, Ltd.