Chemical constituents from Syringa pubescens Turcz

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.

Response surface methodology optimised solvothermal system enables an efficient extraction of echinacoside and oleuropein from Syringa pubescens Turcz

INTRODUCTION

Syringa pubescens Turcz. was reported to be abundant in the Funiu Mountains of Henan Province and can be used to treat hepatitis and cirrhosis. In order to develop and utilise the resource, a fast and simple technique to extract bioactive compounds is needed.

OBJECTIVES

Our aims were to provide an extraction technique of glycosides from S. pubescens and study the antioxidant activity of this material.

METHODS

Box-Behnken design (BBD) was employed with three factors at three levels. The process parameters such as ethanol concentration (X₁ ), temperature (X₂ ), and solvent-solid ratio (X₃ ) could significantly influence efficiency and yield of target compounds. High-performance liquid chromatography (HPLC) was used to determine the content of glycosides. DPPH (α,α-diphenyl-β-picrylhydrazyl), ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) and reducing power were used to evaluate the antioxidant activity of S. pubescens extract.

RESULTS

The optimal parameters for the maximal extraction yield were obtained with ethanol concentration of 68%, temperature of 89°C, solvent-solid ratio of 46 mL/g, and time of 20 min. The S. pubescens extract showed strong antioxidant properties in vitro.

CONCLUSION

The findings indicated the potential application of solvothermal extraction method to extract bioactive compounds from S. pubescens Turcz. Furthermore, the S. pubescens extract could be used as an important resource of antioxidant activity.

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.

The Oleaceae family: A source of secoiridoids with multiple biological activities

In the quest to search and discover bioactive compounds from nature, terpenoids have emerged as one of the most interesting and researched classes of compounds. Secoiridoid, a type of the terpenoid, has also been extensively studied, especially their chemical structures and pharmacological effects. Oleaceae is a family of woody dicotyledonous plants with broad economic and medicinal values. This family contains a large number of flavonoids, monoterpenoids, iridoids, secoiridoids and phenylethyl alcohols, of which the secoiridoids have various biological activities. The purpose of this review is to summarize the phytochemical and pharmacological of the secoiridoids (glycosides, aglycones, derivatives and dimers) in the Oleaceae family from 1987 to 2018. This review will also serve as a reference for further studies.

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.

Secoiridoids and other chemotaxonomically relevant compounds in Pedicularis: phytochemical analysis and comparison of Pedicularis rostratocapitata Crantz and Pedicularis verticillata L. from Dolomites

We compared the respective metabolite patterns of two Pedicularis species from Dolomites. Seven phenylethanoid glycosides, i.e., verbascoside (1), echinacoside (2), angoroside A (3), cistantubuloside B1 (4), wiedemannioside C (5), campneoside II (11) and cistantubuloside C1 (12), together with several iridoid glucosides as aucubin (6), euphroside (7), monomelittoside (8), mussaenosidic acid (9) and 8-epiloganic acid (13) were identified. Pedicularis verticillata showed also the presence of greatly unexpected secoiridoids, ligustroside (14) and excelside B (15), very rare compounds in Lamiales. Both PhGs and iridoids are considered of taxonomical relevance in the Asteridae and their occurrence in Pedicularis was discussed. In particular, the exclusive presence of several compounds such as 8-epiloganic acid (13), campneoside II (11), cistantubuloside C1 (12), ligustroside (14) and excelside B (15) in Pedicularis rostratocapitata, and angoroside A (3), cistantubuloside B1 (4) and wiedemannioside C (5) in P. verticillata could be considered specific markers for the two botanical entities.

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.

Phytochemical and pharmacological progress on the genus Syringa

Genus Syringa, belonging to the Oleaceae family, consists of more than 40 plant species worldwide, of which 22 species, including 18 endemic species, are found in China. Most Syringa plants are used in making ornaments and traditional medicines, whereas some are employed for construction or economic use. Previous studies have shown that extracts of Syringa plants mainly contain iridoids, lignans, and phenylethanoids that have antitumor, antihypertensive, anti-oxidant, and anti-inflammatory activities. This study reviews phytochemical and pharmacological progress on Syringa in the recent 20 years and discusses the future research prospects to provide a reference in further promotion and application of the genus.

Graphical Abstract