Next Article in Journal
Remapping the Chemical Space and the Pharmacological Space of Drugs: What Can We Expect from the Road Ahead?
Next Article in Special Issue
Unlocking Cholesterol Metabolism in Metabolic-Associated Steatotic Liver Disease: Molecular Targets and Natural Product Interventions
Previous Article in Journal
Synthesis, Biological, and Computational Evaluations of Conformationally Restricted NAD-Mimics as Discriminant Inhibitors of Human NMN-Adenylyltransferase Isozymes
Previous Article in Special Issue
Barbaloin Protects Pentylenetetrazol-Induced Cognitive Deficits in Rodents via Modulation of Neurotransmitters and Inhibition of Oxidative-Free-Radicals-Led Inflammation
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Pharmaceuticals
Volume 17
Issue 6
10.3390/ph17060740
pharmaceuticals-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles thumb_up
...
Endorse textsms
...
Comment
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Chemical Compositions of Lianqiao (Forsythia suspensa) Extracts and Their Potential Health Benefits

by
Boyan Gao
1,†,
Hanshu Zhu
1,†,
Zhihao Liu
2,3,
Xiaohua He
4,
Jianghao Sun
3,
Yanfang Li
2,
Xianli Wu
3,
Pamela Pehrsson
3,
Yaqiong Zhang
1,*,
Yuanhang Yao
2,* and
Liangli Yu
2
1
Institute of Food and Nutraceutical Science, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
2
Department of Nutrition and Food Science, University of Maryland, College Park, MD 20742, USA
3
Methods and Application of Food Composition Laboratory, Beltsville Human Nutrition Research Center, Agricultural Research Service, United States Department of Agriculture, Beltsville, MD 20705, USA
4
Western Regional Research Center, Agricultural Research Service, United States Department of Agriculture, Albany, CA 94710, USA
*
Authors to whom correspondence should be addressed.
†
These authors contributed equally to this manuscript.
Pharmaceuticals 2024, 17(6), 740; https://doi.org/10.3390/ph17060740
Submission received: 16 May 2024 / Revised: 29 May 2024 / Accepted: 4 June 2024 / Published: 6 June 2024
(This article belongs to the Special Issue Natural Products in Health Promotion and Disease Prevention 2024)
Browse Figures
Review Reports Versions Notes

Abstract

:
This study evaluated the fruits of Forsythia suspensa (Lianqiao), an important economic crop, for the chemical components of its water and ethanol extracts, inhibitory effects on SARS-CoV-2 virus spike protein binding to ACE2, inhibition of ACE2 activity, and capacity to scavenge free radicals. A total of 42 compounds were tentatively identified in the extracts via HPLC-MS/MS analysis. The water extract showed a greater ACE2 inhibition but a weaker inhibition on SARS-CoV-2 spike protein binding to ACE2 than the ethanol extract on a per-botanical-weight-concentration basis. The phenolic content was found to be greater in the water extract at 45.19 mg GAE/g dry botanical weight than in the ethanol extract (6.89 mg GAE/g dry botanical). Furthermore, the water extract had greater scavenging capacities against HO●, DPPH●, and ABTS●+ at 448.48, 66.36, and 121.29 µmol TE/g dry botanical, respectively, as compared to that of the ethanol extract (154.04, 3.55, and 33.83 µmol TE/g dry botanical, respectively). These results warrant further research into, and the development of, the potential COVID-19-preventive applications of Lianqiao and its extracts.

1. Introduction

According to the World Health Organization (WHO), severe acute respiratory syndrome coronavirus (SARS-CoV-2), responsible for the outbreak of the coronavirus disease 2019 (COVID-19) pandemic, has infected 762,791,152 people and led to 6,897,025 deaths globally [1]. Beyond the vaccines and pharmaceuticals, there is an emerging research trend that has started to direct attention to some alternative remedies, such as utilizing certain bioactive compounds, nutraceuticals, and herbs in reducing the risk of infection and/or relieving the symptoms of SARS-CoV-2. Forsythia suspensa, an important agribotanical primarily grown in China, is well known for its fruit, Lianqiao (Forsythiae fructus), which has been an essential component of antibacterial remedies for decades. It contains many bioactive compounds, including lignans, phenylethanoid glycosides, flavonoids, terpenoids, cyclohexylethanol derivatives, alkaloids, and steroids [2], which endow Lianqiao with antioxidant [3], antibacterial [4], and antiviral [5] activities.
Law et al. reported that Lianqiao extracts prolonged the life span and increased the survival of mice infected with the A/PR/8/34 (H1N1) virus in a dose-dependent manner [6]. Lin et al. collected the clinical data of 77 patients with severe acute respiratory syndrome (SARS) treated with integrated regular and alternative medicines, including botanical foods, and the results showed that the administration of botanical foods, including Lianqiao, had potential in preventing severe SARS cases [7]. Considering the similarity between severe acute respiratory syndrome coronavirus (SARS-CoV-2) spike protein and SARS-CoV spike protein (around 76% to 78%), in ref. [8], the antiviral and anti-inflammatory activity of Lianqiao-related medicine were examined, and results showed that Lianqiao has significant inhibitory effects against the SARS-CoV-2 replication and shows anti-inflammatory activity in vitro [9], which possibly implies that Lianqiao could have potential effects in reducing SARS-CoV-2 infection and the progression of severe COVID-19 symptoms.
According to its pathogenic mechanism, SARS-CoV-2 enters host cells in the same way as SARS-CoV via the angiotensin-converting enzyme 2 (ACE2) receptor. After the binding of SARS-CoV-2 spike (S) protein to the ACE2, the membrane of the virus and the host cell fuses, and the viral RNA is subsequently released into the cytoplasm of the host cell to establish infection [10]. The sites involved in this process might be focused as targets for the development of COVID-19 prevention and/or therapeutics. For example, recombinant human (rh) ACE2 is an ACE2 blocker binding to virus S protein, thus protecting host cells from infection [11].
Although some preliminary studies have suggested that Lianqiao might be one of the possible candidates for reducing the risk of COVID-19 and the severity of its symptoms [9,12], its action site and direct antiviral effects have never been investigated. Therefore, this study was conducted to investigate the chemical compositions of Lianqiao water and ethanol extracts, their potential effects on the binding of SARS-CoV-2 spike protein to ACE2, their inhibition of ACE2 activity, and their scavenging capacities against hydroxyl (HO●), DPPH●, and ABTS●+ radicals. The present study aims to elucidate the inhibitory effects of Lianqiao on ACE2-mediated viral invasion and can hopefully provide scientific support for the development of Lianqiao and its derivatives as functional foods for COVID-19 prevention.

2. Results and Discussion

Chemical compositions of the Lianqiao (Forsythia suspensa fruit) extracts: The LC-MS chromatograms of Lianqiao water and ethanol extracts in positive- and negative-ionization modes are shown in Figure S1. A total of 42 compounds were tentatively identified referring to high-resolution MS, MS2 fragment information, and a literature review. Among these compounds, there were 8 lignans (30, 32–35, 37, 38, 40), 9 phenylethanoid glycosides (4, 9, 13, 18, 20, 26–29), 5 terpenoids (16, 36, 39, 41, 42), 11 phenolics (1, 3, 5, 8, 11, 12, 14, 19, 21, 23, 25), and 9 other compounds (Table 1). As shown in Table 1, Lianqiao samples with different extraction solvents were observed with varied identified compounds and different relative contents. Generally, 37 compounds were detected and identified in Lianqiao water extracts, and 25 compounds were identified in ethanol extracts. Some identified compounds had the same elemental composition, molecular formula, and similar fragment information, making it impossible to determine their specific substance attribution, and they were all marked as isomers in this article. For the relative contents, halleridone (7), forsythialan B (35), (+)-1-hydroxylpinoresinol (33), plantasioside (24), and forsythoside H (26) were the five major compounds in water extracts; whereas forsythialan B (35), (+)-1-hydroxylpinoresinol (33), azelaic acid (31), epipinoresinol-4’-β-D-glucopyranoside (32), and forsythoside H (26) were the top five ethanol extracts. Forsythialan B (35), (+)-1-hydroxylpinoresinol (33), and forsythoside H (26) could be recognized as the three primary compounds in both Lianqiao water and ethanol extracts. Compounds 28, 35, and 18 were selected as examples with which to elucidate the identification progress. The rest of the major chemical components in the Lianqiao extracts were identified consistently using the approaches described below.
For compound 28, the molecular ion detected in the positive-ion mode ([M + H]+) is m/z 625.21246, which is consistent with C29H37O15 (mass precision, −0.379 ppm), indicating that the molecular formula of compound 28 is C29H36O15. The main fragment ions in the normal mode are 479.1540 [M + H − Ara]+, 471.1494 [M + H − C8H10O3]+, and 325.0915 [M + H − Ara − C8H10O3]+. According to these results and the literature, compound 28 was identified as forsythoside A, a type of phenylethanoid glycosides. Forsythoside A has been proven to have antioxidant, anti-inflammatory, and antiviral activities, and is known as one of the representative active substances in Lianqiao [17,18,19]. The content of forsythoside has been designated as a marker for Lianqiao’s quality control according to Chinese Pharmacopoeia (2015 Edition) [20].
For compound 35, in the positive-ion mode ([M + H]+), the molecular ion is m/z 389.15921, which is consistent with C21H25O7 (mass accuracy: −0.693 ppm). And in the negative-ion mode ([M − H]–) the molecular ion is m/z 387.14408, which is consistent with C21H23O7 (mass accuracy: 0.647 ppm). These results indicate that the molecular formula of compound 35 is C21H24O7. The fragment ions detected in the positive mode are at m/z 371.1485 [M + H − H2O]+, 247.0963 [M + H − H2O − 124]+, and 217.0858 [M + H − H2O − 124 − CH2O]+. The fragment ions of [M + H − H2O − 124]+ are formed by the reduction of methoxyphenol group. The major fragment ion in the negative mode is 372.1202 [M − H − CH3]–. Based on these results and the literature review, compound 35 was identified as forsythialan B. Forsythialan B is a tetrahydrofuran, one of the representative lignans in Lianqiao, which has been proven to be protective against peroxynitrite-induced oxidative stress [21].
For compound 18 (Figure 1), the molecular ion is m/z 487.14523 in the negative mode ([M − H]–), which is consistent with C21H27O13 (mass accuracy: 1.258 ppm) and indicates its molecular formula of C21H28O13. The fragment ions detected in the negative-ion mode are at m/z 469.1335 [M − H − H2O]–, 427.1229 [M − H − H2O − C2H2O]–, 397.1122 [M − H − H2O − C2H2O − CH2O]−, 233.0445 [M − H − H2O − C2H2O − CH2O − O-Ara]–, 203.0340 [M − H − H2O − C2H2O − CH2O − O-Ara − CH2O]−, and 179.0341 [M − H − H2O − C2H2O − CH2O − O-Ara − CH2O − C2]−. Based on the data we collected and the existing evidence from the literature, compound 18 was tentatively identified as cistanoside F. To the best of our knowledge, cistanoside F was found in Lianqiao extracts for the first time, but it has been found in other botanicals before [22,23].
Inhibitory effects of Lianqiao extracts on SARS-CoV-2 spike protein and ACE2 interaction: Significant differences were observed in the inhibitory effects of SARS-CoV-2 spike protein and ACE2 interaction between Lianqiao water and ethanol extracts (Figure 2). Notably, the water extract at 33.3 mg dry botanical equivalents/mL in the testing mixture (WE33.3) inhibited 84.34% of the interaction activity. Meanwhile, 3.3 mg dry botanical equivalents/mL in the testing mixture (WE3.3) inhibited only 1.43% of the interaction activity, while the ethanol extracts (EE3.3) inhibited 45.57% of the interaction activity at the same concentration. At a concentration of 1.7 mg dried botanical equivalent/mL, the ethanol extracts (EE1.7) were observed with a 7.45% inhibition of SARS-CoV-2 spike protein binding to ACE2. However, the inhibitory effects were negligible, with a similar concentration of the water extracts. This is possible because the ethanol extracts of Lianqiao exhibit greater activity in inactivating and denaturing the SARS-CoV-2 virus [24]. Given that SARS-CoV-2 enters host cells by binding ACE2 as the receptor, intervention and inhibition of this process may be one of the key points for preventing infection and relieving the symptoms of COVID-19.
Inhibitory effects of the Lianqiao extracts on ACE2 enzyme activity: Both Lianqiao water and ethanol extracts exhibited inhibitory effects on ACE2 activity (Figure 3). Specifically, the initial water extracts (5.0 mg dry botanical equivalents/mL in the testing mixture, WE5.0) inhibited 77.82% of ACE2 activity, and an inhibition of 14.93% was observed with the initial water extracts at a concentration of 0.5 mg dry botanical equivalents/mL (WE0.5). In contrast, the initial ethanol extracts (5.0 mg dry botanical equivalents/mL, EE5.0) inhibited 68.33% of ACE2 activity, which was about 12.2% lower than the water extracts at the same concentration. Current evidence suggests that ACE2 is the receptor by which SARS-CoV-2 enters host cells, and coronavirus aggravates infection by upregulating ACE2 expression via interferon [25,26]. Therefore, the inhibition of its own activity may be one approach to interfering with the infection process. However, it is worth noting that ACE2 is also a critical component of the renin–angiotensin system (RAS), which regulates pathological responses such as blood pressure, inflammation, and oxidative stress [10,27]. And further research is still needed to determine the possible inhibition effects of ACE2 activity via Lianqiao extracts in simultaneously inducing some other side effects.
Total phenolic contents (TPC) and antioxidant assays of Lianqiao extracts: Phenolics are capable of scavenging free radicals or chelating metals, which competitively inhibit the oxidation process [28]. The TPC values of Lianqiao water and ethanol extracts were 45.19 and 6.89 mg GAE/g dry botanical, respectively (Figure 4). The TPC values of the Lianqiao water extracts in the present study were more remarkable than those of a previous study, which were reported to be 13.2–13.9 mg GAE/g dry botanical from Lianqiao methanol (70%, v/v) extracts [3]. These results indicate that different extraction methods might lead to substantial differences in the TPC of Lianqiao extracts, which aligns with our chemical profile findings.
Free radicals in biological systems can damage a variety of cell components and cause adverse effects. For instance, peroxidation of membrane phospholipids changes the fluidity and permeability of cell membranes, leading to cell dysfunction or even death, which will thereby result in metabolic disorders and a variety of diseases [29]. Meanwhile, the reactive oxygen species (ROS) have also been discovered to be involved in the pathogenesis of neurodegenerative diseases [30], atherosclerosis [31], asthma [32], and chronic kidney diseases [33]. In COVID-19, SARS-CoV-2 unbalances oxidative homeostasis and stimulates the production of ROS, triggers an inflammatory reaction, and then causes organ failure [34]. Cytokine storm, a severe inflammatory reaction mediated by oxidative stress, leads to even more severe symptoms [25,34]. Therefore, evaluating the antioxidant abilities of certain components is essential when developing potential nutraceuticals for COVID-19 treatment. Considering the difference in mechanisms of action and the targeted free radicals, three free-radical-scavenging assays, including HOSC, RDSC, and ABTS, were selected to examine the in vitro antioxidant effects of Lianqiao extracts.
The free-radical-scavenging capacities of Lianqiao water and ethanol extracts are shown in Figure 5. The HOSC, RDSC, and ABTS values of the water extracts were 448.48, 66.36, and 121.29 µmol TE/g, respectively, which were significantly greater than those of the ethanol extracts (154.04, 3.55, and 33.83 µmol TE/g, respectively). Overall, the results suggested that both Lianqiao water and ethanol extracts possessed considerable antioxidant capacities, whereas Lianqiao water extracts had a superior antioxidant capacity than ethanol extract. The higher antioxidant capacity of Lianqiao water extract might be due to its higher total phenolic content shown in Figure 4. Specifically, for the HOSC assay, the extracts of Lianqiao showed significant efficacy in scavenging hydroxyl radicals, which is of clinical importance due to the critical role that hydroxyl radicals play in irreversible damage caused by oxidative stress in our body [35]. It is worth noting that the antiradical activity inhibited by using stable free radicals, such as DPPH and ABTS, may not be fully representative of the antioxidant activity of the tested samples, and they do not exist in biological systems [35]. Therefore, further research is needed to validate the antioxidant activity of Lianqiao extracts with an in vivo study design.

3. Materials and Methods

Materials: Lianqiao samples (Forsythia suspensa fruit) of Chinese Pharmacopeia grade were obtained from a local pharmacy (Rockville, MD, USA). Antioxidant-assays-related chemical reagents, including the Folin–Ciocalteu reagent (FC reagent), sodium carbonate (Na2CO3), gallic acid, 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox), fluorescein (FL), disodium hydrogen phosphate dodecahydrate (Na2HPO4·12H2O), sodium dihydrogen phosphate dehydrate (NaH2PO4), ferric chloride (FeCl3), hydrogen peroxide (H2O2) (30%), 2,2-diphenyl-1-picrylhydrazyl (DPPH•), and 2,2′azinobis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), were purchased from Sigma-Aldrich (St. Louis, MO, USA). Formic acid and acetonitrile (LC-MS grade) were obtained from Merck (Darmstadt, Germany). ACE2 Inhibitor Screening Assay Kit (No. 502100) and SARS-CoV-2 spike ACE2 interaction Inhibitor Screening Assay Kit (No. 502050) were purchased from Cayman (Ann Arbor, MI, USA). All other chemicals used in this study were of analytical-grade purity and purchased from Fisher Scientific (Hampton, NH, USA) without further processing.
Sample preparation and extraction: Lianqiao fruit samples were ground using a micromill grinder (Bel Art Products, Pequannock, NJ, USA) to a particle size of 0.42 mm powder. For water extraction, Lianqiao powder was extracted with ultrapure water in a water bath at 85 °C for an initial 2 h (1:10, w/v) and was then extracted for 22 h at ambient temperature. For ethanol extraction, the powder was extracted with pure ethanol for an entire 24 h at ambient temperature (1:10, w/v). Then, water and ethanol extracts were centrifuged, and the supernatants were stored at −20 °C before analyses.
Chemical compositions of Lianqiao (Forsythia suspensa fruit): To separate and analyze the chemical compositions of Lianqiao water and ethanol extracts, a Vanquish UHPLC (Thermo Fisher Scientific, Norristown, PA, USA) and an Orbitrap Fusion ID-X Tribrid mass spectrometer (Thermo Fisher Scientific, Norristown, PA, USA) were used. Chemical components in Lianqiao extract samples were separated using an Agilent Eclipse Plus-C18 UHPLC column (150 mm × 2.1 mm, 1.8 μm) (Santa Clara, CA, USA) connected after an UltraShield pre-column (Santa Clara, CA, USA), with an injection volume of 1 μL. And 0.1% formic acid in water (v/v) and 0.1% formic acid in acetonitrile (v/v) were used as mobile phases A and B, respectively. The column was pre-equilibrated with 2% B for 5 min; then the linear gradient was programmed as follows: 0 min, 2% B; 15 min, 10% B; 35 min, 40% B; and 55 min, 95% B, lasting until 60 min and then re-equilibrated the column with 2% B for 10 min. The flow rate was 0.3 mL/min throughout the injection. For the high-resolution mass spectrometry analyses, the mass scanning process took 39 min in the scan range of m/z 120−1200. The spray voltages in positive- and negative-ion modes were set to 3900 and 2500 V, respectively. The temperature of the ion transport tube was kept at 300 °C, and the temperature of the vaporizer was 275 °C. The chemical compounds in Lianqiao water and ethanol extracts were determined by their molecular weights, mass fragment information, previously published related manuscripts, and chemical databases, including SciFinder and ChemSpider.
Inhibitory effects of Lianqiao extracts on SARS-CoV-2 spike protein and ACE2 interaction: To detect the inhibitory effects of Lianqiao extracts on the binding of SARS-CoV-2 spike protein and ACE2, a Cayman SARS-CoV-2 spike ACE2 interaction inhibitor screening assay kit was used (No. 502050). The procedure was performed following the protocol of the product. Briefly, 100 µL of buffer (Immunoassay Buffer C (1X)) and 50 µL of ACE2 inhibitor screening reagent were added to a 96-well plate as the background. For the control sample, 50 µL of buffer, 50 µL of ACE2 inhibitor screening reagent, and 50 µL of spike inhibitor screening reagent were added to the 100% initial activity wells. For the tested sample, 50 µL of Lianqiao extract sample solution, 50 µL ACE2 inhibitor screening reagent, and 50 µL of spike inhibitor screening reagent were added to the sample wells. The 96-well plate was covered and incubated for 60 min at ambient temperature with shaking. Then, the plate was emptied and rinsed five times with wash buffer; then, 150 µL of anti-His HRP conjugate was added. The plate was incubated at room temperature with shaking for 30 min, and the washing procedure was repeated. A volume of 175 µL of TMB substrate solution was added to each well, and the plate was incubated again at ambient temperature with shaking for 15 min. A volume of 75 µL of HRP stop solution was added to each well to terminate the reaction, and absorbance was read at 450 nm using Tecan M200 Pro microplate reader (Tecan Group Ltd., Mannedorf, Switzerland). The results were shown as the percentage (%) inhibition:
% i n h i b i t i o n = A b s S a m p l e − A b s B a c k g r o u n d A b s 100 % I n i t i a l − A b s B a c k g r o u n d × 100 % .
Inhibitory effects of Lianqiao extracts on ACE2 enzyme activity: A Cayman ACE2 Inhibitor Screening Assay Kit (No. 502100) was used to determine the ACE2 inhibitory effects of Lianqiao extracts. The procedure was performed following the protocol of the product. Briefly, 5 µL solvent and 85 µL ACE2 assay buffer were added to the background wells. For the control reaction, 5 µL solvent, 75 µL ACE2 assay buffer, and 10 µL of ACE2 enzyme were added to the 100% initial activity wells. And 5 µL of Lianqiao extract sample solution, 75 µL of ACE2 assay buffer, and 10 µL diluted ACE2 enzyme were added to the sample reaction wells. A volume of 10 µL of ACE2 substrate was added to all wells to start the reactions. The 96-well plate was covered and incubated for 30 min at ambient temperature in the dark. After the incubation, the fluorescence (AF) (λex = 320 nm; λem = 405 nm) of the plate was read using a Tecan M200 Pro microplate reader (Tecan Group Ltd., Mannedorf, Switzerland). The results were shown as the percentage (%) inhibition:
% i n h i b i t i o n = 1 − A F S a m p l e − A F B a c k g r o u n d A F 100 % I n i t i a l − A F B a c k g r o u n d × 100 % .
Total phenolic content (TPC) determination: Total phenolic contents (TPC) of Lianqiao water and ethanol extracts were examined following the laboratory protocol [36]. One aliquot of 3 mL of ultrapure water, 50 µL of Lianqiao extraction sample, gallic acid standards or solvent, and 250 µL of FC reagent were added to a test tube and vortexed for 5 s to mix well. After waiting 5 min, 750 µL of 20% (w/v) Na2CO3 was added to activate the reaction. The tubes were covered with parafilm and aluminum foil for 2 h at ambient temperature in the dark. Then, the spectrophotometer was blanked at 765 nm using a blank solution, and the absorbances of all standard and sample solutions at 765 nm were measured with a multifunction microplate reader (Tecan M200 Pro, Tecan Group Ltd., Mannedorf, Switzerland). The TPC of Lianqiao water and ethanol extracts was showed as milligram gallic acid equivalents per gram of Lianqiao sample (mg GAE/g).
Relative hydroxy radical scavenging capacity (HOSC): HOSC values of the Lianqiao water and ethanol extracts were tested following the laboratory protocol [37]. Fresh prepared working solutions, including 170 µL of working FL solution, 30 µL of sample, Trolox standards or blank, 40 µL of H2O2 working solution, and 60 µL of FeCl3 working solution were mixed in a 96-well plate. After shaking for 15 s, the fluorescence intensities (λex = 485 nm; λem = 528 nm) of each well were measured every 5 min for 5 h by Tecan M200 Pro microplate reader (Tecan Group Ltd., Mannedorf, Switzerland). The area under the curve (AUC) was measured, and the HOSC values of Lianqiao extracts were showed as Trolox equivalent per gram of Lianqiao sample (µmoles TE/g).
Relative DPPH● scavenging capacity (RDSC): The RDSC values of the Lianqiao water and ethanol extracts were determined following our previously published protocol [38]. In a 96-well plate, 200 µL of solvent was used as blank, 100 µL of the sample, and Trolox standards or solvent were added together with 100 µL of DPPH● working solution (0.2 mM). The absorbance at 515 nm was measured every minute for 90 min using Tecan M200 Pro microplate reader (Tecan Group Ltd., Mannedorf, Switzerland). After calculating the AUCs, the RDSC values of Lianqiao extracts were expressed as µmol Trolox equivalent per gram of Lianqiao sample (µmoles TE/g).
Relative ABTS●+ scavenging capacity (ABTS): The ABTS values of the Lianqiao water and ethanol extracts were tested [39]. The ABTS•+ working solution was diluted to absorbance at 0.700 with the monitor of spectrometer at 734 nm. Then 2 mL ABTS•+ working solution, 160 µL of sample, or Trolox standards were mixed to start the reaction and vortexed for 30 s. The mixture was transferred to a cuvette, and the absorbance at 734 nm was measured exactly 90 s after the initial of reaction with a Genesys 20 visible spectrophotometer (Thermo Fisher Scientific, Norristown, PA, USA). The ABTS values of Lianqiao water and ethanol extracts were showed as µmol Trolox equivalent per gram of Lianqiao sample (µmoles TE/g).
Statistical analysis: All the experiments were carried out in triplicate, and the data were presented as mean ± standard deviation (SD). The t-test was conducted to determine the differences in the inhibitory and radical scavenging activities and the total phenolic content between Lianqiao water and ethanol extracts using IBM SPSS Statistics (version 25.0, SPSS, Inc., Chicago, IL, USA), and p < 0.05 was considered statistically significant. The mass data and spectra were obtained and analyzed by XcaliburTM (Version 4.2, Thermo Fisher Scientific, Norristown, PA, USA). All the figures were charted using GraphPad Prism (version 8.0, Graphpad Software Inc., San Diego, CA, USA).

4. Conclusions

In conclusion, this present study managed to identify the chemical components of Lianqiao water and ethanol extracts, and Cistanoside F was found in Lianqiao extracts for the first time. This study has contributed to a preliminarily understanding of the effects of Lianqiao water and ethanol extracts in preventing and/or treating SARS-CoV-2-related infections by evaluating the SARS-CoV-2 spike protein and ACE2 interaction, ACE2 enzyme activity, and antioxidant capacities. The Lianqiao water extract showed stronger inhibition on the activity of ACE2 than the ethanol extract, but its inhibitory effects on the binding of SARS-CoV-2 spike protein and ACE2 was weaker than that of ethanol. In addition, the scavenging capacities of water extract on HO●, DPPH●, and ABTS●+ were stronger than those of ethanol extract. These suggest that the extraction solvents matter and are likely to result in different extracted components and bioactivities. Taken together, this study provides scientific support for the application of Lianqiao as a potential integrant for the prevention and treatment of SARS-CoV-2 infection and contributes to the study of an alternative remedy for COVID-19 utilizing Lianqiao extracts.

Supplementary Materials

The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/ph17060740/s1, Figure S1. Chromatogram of Lianqiao water extract (WE) in positive (A) and negative (B) ionization modes, and Lianqiao ethanol extract (EE) in positive (C) and negative (D) ionization modes.

Author Contributions

Conceptualization, Y.Z. and L.Y.; Methodology, Z.L.; Validation, J.S.; Investigation, B.G., H.Z., Y.L. and X.W.; Data curation, X.H.; Writing—original draft, B.G.; Writing—review & editing, P.P., Y.Z., Y.Y. and L.Y.; Funding acquisition, B.G. and Y.Z. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by the National Key R&D Program of China (2023YFF1104304) and the National Natural Science Foundation of China (Grant No. 32272426).

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The original contributions presented in the study are included in the article/supplementary material, further inquiries can be directed to the corresponding author/s.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. WHO. Available online: https://covid19.who.int/ (accessed on 3 May 2024).
  2. Wang, Z.; Xia, Q.; Liu, X.; Liu, W.; Huang, W.; Mei, X.; Luo, J.; Shan, M.; Lin, R.; Zou, D.; et al. Phytochemistry, pharmacology, quality control and future research of Forsythia suspensa (Thunb.) Vahl: A review. J. Ethnopharmacol. 2018, 210, 318–339. [Google Scholar] [CrossRef] [PubMed]
  3. Cheng, Q.; Li, S.; Zhang, L. Study on comparison of antioxidant activity and determination of total phenol content in different parts of Forsythia suspensa. Chem. Res. App. 2016, 28, 610–616. [Google Scholar]
  4. Liu, S.; Xu, Y.; Zheng, Y. Effect of the ethanol extract of Forsythia suspensa (Thunb.) Vahl. on the growth curve of bacterium. J. Anhui Agri. Sci. 2007, 35, 7383–7384. [Google Scholar]
  5. Tian, W.; Li, H.; Yao, Z.; Dong, Y.; Qiu, H.; Han, Z. Inhibition of respiratory syncytial virus by Forsythia suspensa (Thunb.) Vahl. J. Harbin Med. Coll. 2004, 38, 421–423. [Google Scholar]
  6. Law, A.H.; Yang, C.L.; Lau, A.S.; Chan, G.C. Antiviral effect of forsythoside A from Forsythia suspensa (Thunb.) Vahl fruit against influenza A virus through reduction of viral M1 protein. J. Ethnopharmacol. 2017, 209, 236–247. [Google Scholar] [CrossRef] [PubMed]
  7. Lin, L.; Xu, Y.; He, D.; Han, Y.; Tang, G.; Yang, Z.-M.; Yu, H.; Lin, Z. A retrospective study on clinical features of and treatment methods for 77 severe cases of SARS. Am. J. Chin. Med. 2003, 31, 821–839. [Google Scholar] [CrossRef] [PubMed]
  8. Wan, Y.; Shang, J.; Graham, R.; Baric, R.S.; Li, F. Receptor recognition by the novel coronavirus from Wuhan: An analysis based on decade-long structural studies of SARS coronavirus. J. Virol. 2020, 94, e00127-20. [Google Scholar] [CrossRef] [PubMed]
  9. Runfeng, L.; Yunlong, H.; Jicheng, H.; Weiqi, P.; Qinhai, M.; Yongxia, S.; Chufang, L.; Jin, Z.; Zhenhua, J.; Haiming, J.; et al. Lianhuaqingwen exerts anti-viral and anti-inflammatory activity against novel coronavirus (SARS-CoV-2). Pharmacol. Res. 2020, 156, 104761. [Google Scholar] [CrossRef]
  10. Ni, W.; Yang, X.; Yang, D.; Bao, J.; Li, R.; Xiao, Y.; Hou, C.; Wang, H.; Liu, J.; Yang, D.; et al. Role of angiotensin-converting enzyme 2 (ACE2) in COVID-19. Crit. Care 2020, 24, 422. [Google Scholar] [CrossRef]
  11. Zhang, J.; Xie, B.; Hashimoto, K. Current status of potential therapeutic candidates for the COVID-19 crisis. Brain Behav. Immun. 2020, 87, 59–73. [Google Scholar] [CrossRef]
  12. Luo, H.; Tang, Q.L.; Shang, Y.X.; Liang, S.B.; Yang, M.; Robinson, N.; Liu, J.P. Can Chinese Medicine Be Used for Prevention of Corona Virus Disease 2019 (COVID-19)? A Review of Historical Classics, Research Evidence and Current Prevention Programs. Chin. J. Integr. Med. 2020, 26, 243–250. [Google Scholar] [CrossRef] [PubMed]
  13. Zhou, M.; Huo, J.; Wang, C.; Wang, W. UPLC/Q-TOF MS screening and identification of antibacterial compounds in Forsythia suspensa (Thunb.) Vahl leaves. Front. Pharmacol. 2021, 12, 704260. [Google Scholar] [CrossRef]
  14. Sun, H.; Liu, M.; Lin, Z.; Jiang, H.; Niu, Y.; Wang, H.; Chen, S. Comprehensive identification of 125 multifarious constituents in Shuang-huang-lian powder injection by HPLC-DAD-ESI-IT-TOF-MS. J. Pharm. Biomed. Anal. 2015, 115, 86–106. [Google Scholar] [CrossRef] [PubMed]
  15. Liu, M.-H.; Tong, X.; Wang, J.-X.; Zou, W.; Cao, H.; Su, W.-W. Rapid separation and identification of multiple constituents in traditional Chinese medicine formula Shenqi Fuzheng Injection by ultra-fast liquid chromatography combined with quadrupole-time-of-flight mass spectrometry. J. Pharm. Biomed. Anal. 2013, 74, 141–155. [Google Scholar] [CrossRef] [PubMed]
  16. Abu-Reidah, I.M.; Arráez-Román, D.; Quirantes-Piné, R.; Fernández-Arroyo, S.; Segura-Carretero, A.; Fernández-Gutiérrez, A. HPLC-ESI-Q-TOF-MS for a comprehensive characterization of bioactive phenolic compounds in cucumber whole fruit extract. Food Res. Int. 2012, 46, 108–117. [Google Scholar] [CrossRef]
  17. Li, H.; Wu, J.; Zhang, Z.; Ma, Y.; Liao, F.; Zhang, Y.; Wu, G. Forsythoside a inhibits the avian infectious bronchitis virus in cell culture. Phytother. Res. 2011, 25, 338–342. [Google Scholar] [CrossRef] [PubMed]
  18. Guo, Y.P.; Lin, L.G.; Wang, Y.T. Chemistry and pharmacology of the herb pair Flos Lonicerae japonicae-Forsythiae fructus. Chin. Med. 2015, 10, 16. [Google Scholar] [CrossRef]
  19. Lin, H.; Li, C.L.; Yen, L.J.; Lu, L.Y.; Huang, H.S.; Liao, E.C.; Yu, S.J. Forsythoside A Alleviates Imiquimod-Induced Psoriasis-like Dermatitis in Mice by Regulating Th17 Cells and IL-17A Expression. J. Pers. Med. 2022, 12, 62. [Google Scholar] [CrossRef]
  20. Chinese Pharmacopoeia; China Medical Science Press: Beijing, China, 2015; Available online: https://www.webofpharma.com/2021/05/chinese-pharmacopoeia-in-english-cp-15.html (accessed on 8 November 2023).
  21. Piao, X.L.; Jang, M.H.; Cui, J.; Piao, X. Lignans from the fruits of Forsythia suspensa. Bioorg. Med. Chem. Lett. 2008, 18, 1980–1984. [Google Scholar] [CrossRef]
  22. Ma, Z.; Yang, Z.; Li, P.; Li, C. Simultaneous determination of eight phenylethanoid glycosides in different species of the genus cistanche by high performance liquid chromatography. J. Liq. Chromatogr. Relat. Technol. 2008, 31, 2838–2850. [Google Scholar] [CrossRef]
  23. Murayama, T.; Yanagisawa, Y.; Kasahara, A.; Onodera, K.-I.; Kurimoto, M.; Ikeda, M. A novel phenylethanoid, isocrenatoside isolated from the whole plant of Orobanche coerulescens. J. Nat. Med. 1998, 52, 455–458. [Google Scholar]
  24. Kratzel, A.; Todt, D.; V’Kovski, P.; Steiner, S.; Gultom, M.; Thao, T.T.N.; Ebert, N.; Holwerda, M.; Steinmann, J.; Niemeyer, D.; et al. Inactivation of severe acute respiratory syndrome coronavirus 2 by WHO-recommended hand rub formulations and alcohols. Emerg. Infect. Dis. 2020, 26, 1592–1595. [Google Scholar] [CrossRef]
  25. Kielbowski, K.; Herian, M.; Pawlik, A. How to restore oxidative balance that was disrupted by SARS-CoV-2 infection. Int. J. Mol. Sci. 2022, 23, 6377. [Google Scholar] [CrossRef] [PubMed]
  26. Ziegler, C.G.K.; Allon, S.J.; Nyquist, S.K.; Mbano, I.M.; Miao, V.N.; Tzouanas, C.N.; Cao, Y.; Yousif, A.S.; Bals, J.; Hauser, B.M.; et al. SARS-CoV-2 receptor ACE2 is an interferon-stimulated gene in human airway epithelial cells and is detected in specific cell subsets across tissues. Cell 2020, 181, 1016–1035. [Google Scholar] [CrossRef] [PubMed]
  27. Fazio, S.; Affuso, F.; Bellavite, P. A review of the potential roles of antioxidant and anti-Inflammatory pharmacological approaches for the management of mild-to-moderate symptomatic COVID-19. Med. Sci. Monit. 2022, 28, e936292. [Google Scholar] [CrossRef] [PubMed]
  28. Shahidi, F.; Ambigaipalan, P. Phenolics and polyphenolics in foods, beverages and spices: Antioxidant activity and health effects—A review. J. Funct. Foods 2015, 18, 820–897. [Google Scholar]
  29. Bast, A.; Goris, R.J.A. Oxidative stress—Biochemistry and human disease. Pharm. Weekbl. 1989, 11, 199–206. [Google Scholar] [CrossRef] [PubMed]
  30. Liu, J.; Mori, A. Stress, aging, and brain oxidative damage. Neurochem. Res. 1999, 24, 1479–1497. [Google Scholar] [CrossRef] [PubMed]
  31. Loscalzo, J. Oxidant stress: A key determinant of atherothrombosis. Biochem. Soc. Trans. 2003, 31, 1059–1061. [Google Scholar] [CrossRef]
  32. Caramori, G.; Papi, A. Oxidants and asthma. Thorax 2004, 59, 170–173. [Google Scholar] [CrossRef]
  33. Small, D.M.; Coombes, J.S.; Bennett, N.; Johnson, D.W.; Gobe, G.C. Oxidative stress, anti-oxidant therapies and chronic kidney disease. Nephrology 2012, 17, 311–321. [Google Scholar] [CrossRef] [PubMed]
  34. Soto, M.E.; Guarner-Lans, V.; Soria-Castro, E.; Manzano Pech, L.; Pérez-Torres, I. Is antioxidant therapy a useful complementary measure for COVID-19 treatment? An algorithm for its application. Medicina 2020, 56, 386. [Google Scholar] [CrossRef] [PubMed]
  35. Tirzitis, G.; Bartosz, G. Determination of antiradical and antioxidant activity: Basic principles and new insights. Acta Biochim. Pol. 2010, 57, 139–142. [Google Scholar] [CrossRef] [PubMed]
  36. Yu, L.; Perret, J.; Harris, M.; Wilson, J.; Haley, S. Antioxidant Properties of Bran Extracts from “Akron” Wheat Grown at Different Locations. J. Agric. Food Chem. 2003, 51, 1566–1570. [Google Scholar] [CrossRef] [PubMed]
  37. Moore, J.; Yin, J.-J.; Yu, L.L. Novel Fluorometric Assay for Hydroxyl Radical Scavenging Capacity (HOSC) Estimation. J. Agric. Food Chem. 2006, 54, 617–626. [Google Scholar] [CrossRef]
  38. Cheng, Z.; Moore, J.; Yu, L.L. High-throughput relative DPPH radical scavenging capacity assay. J. Agric. Food Chem. 2006, 54, 7429–7436. [Google Scholar] [CrossRef]
  39. Zhou, K.; Su, L.; Yu, L.L. Phytochemicals and antioxidant properties in wheat bran. J. Agric. Food Chem. 2004, 52, 6108–6114. [Google Scholar] [CrossRef]
Pharmaceuticals 17 00740 g001
Figure 1. Identification of cistanoside F (compound 18). Full-scan MS (A) and MS2 (B) in negative-ionization mode—summarization of inferred fragmentation approaches of [M − H]− at m/z 487.1452 (C).
Figure 1. Identification of cistanoside F (compound 18). Full-scan MS (A) and MS2 (B) in negative-ionization mode—summarization of inferred fragmentation approaches of [M − H]− at m/z 487.1452 (C).
Pharmaceuticals 17 00740 g001
Pharmaceuticals 17 00740 g002
Figure 2. Inhibitory effects of Lianqiao (A) water and (B) ethanol extracts at different concentrations on binding interaction between SARS-CoV-2 spike protein and ACE2. WE33.3 and WE3.3 stand for the water extracts at concentrations of 33.3 and 3.3 mg dry Lianqiao equivalents/mL in the testing mixture, respectively. EE3.3 and EE1.7 stand for ethanol extracts at concentrations of 3.3 and 1.7 mg dry Lianqiao equivalents/mL in the testing mixture, respectively. Results are expressed as mean ± SD of experiments performed in triplicate, and values are on a dry botanical weight basis. * indicates significant differences (p < 0.05).
Figure 2. Inhibitory effects of Lianqiao (A) water and (B) ethanol extracts at different concentrations on binding interaction between SARS-CoV-2 spike protein and ACE2. WE33.3 and WE3.3 stand for the water extracts at concentrations of 33.3 and 3.3 mg dry Lianqiao equivalents/mL in the testing mixture, respectively. EE3.3 and EE1.7 stand for ethanol extracts at concentrations of 3.3 and 1.7 mg dry Lianqiao equivalents/mL in the testing mixture, respectively. Results are expressed as mean ± SD of experiments performed in triplicate, and values are on a dry botanical weight basis. * indicates significant differences (p < 0.05).
Pharmaceuticals 17 00740 g002
Pharmaceuticals 17 00740 g003
Figure 3. ACE2 inhibitory effects of Lianqiao (A) water and (B) ethanol extracts at different concentrations. WE5.0 and WE0.5 stand for the water extracts at concentrations of 5.0 and 0.5 mg dry Lianqiao equivalents/mL in the testing mixture, respectively; EE5.0 and EE0.5 stand for the ethanol extracts at concentrations of 5.0 and 0.5 mg dry Lianqiao equivalents/mL in the testing mixture, respectively. Results are expressed as mean ± SD of experiments performed in triplicate, and values are on a dry botanical weight basis. * indicates significant differences (p < 0.05).
Figure 3. ACE2 inhibitory effects of Lianqiao (A) water and (B) ethanol extracts at different concentrations. WE5.0 and WE0.5 stand for the water extracts at concentrations of 5.0 and 0.5 mg dry Lianqiao equivalents/mL in the testing mixture, respectively; EE5.0 and EE0.5 stand for the ethanol extracts at concentrations of 5.0 and 0.5 mg dry Lianqiao equivalents/mL in the testing mixture, respectively. Results are expressed as mean ± SD of experiments performed in triplicate, and values are on a dry botanical weight basis. * indicates significant differences (p < 0.05).
Pharmaceuticals 17 00740 g003
Pharmaceuticals 17 00740 g004
Figure 4. Total phenolic content (TPC) of Lianqiao water (WE) and ethanol extracts (EE). Results are expressed as mean ± SD of experiments performed in triplicate, and values are on a dry botanical weight basis. * indicates significant differences (p < 0.05).
Figure 4. Total phenolic content (TPC) of Lianqiao water (WE) and ethanol extracts (EE). Results are expressed as mean ± SD of experiments performed in triplicate, and values are on a dry botanical weight basis. * indicates significant differences (p < 0.05).
Pharmaceuticals 17 00740 g004
Pharmaceuticals 17 00740 g005
Figure 5. Relative free radical scavenging activities of Lianqiao water (WE) and ethanol extracts (EE) against (A) HO●, (B) DPPH●, and (C) ABTS●+. Results are expressed as mean ± SD of experiments performed in triplicate, and values are on a dry botanical weight basis. * indicates significant differences (p < 0.05).
Figure 5. Relative free radical scavenging activities of Lianqiao water (WE) and ethanol extracts (EE) against (A) HO●, (B) DPPH●, and (C) ABTS●+. Results are expressed as mean ± SD of experiments performed in triplicate, and values are on a dry botanical weight basis. * indicates significant differences (p < 0.05).
Pharmaceuticals 17 00740 g005
Table 1. Characterization of compounds identified in Forsythia suspensa fruit (Lianqiao).
Table 1. Characterization of compounds identified in Forsythia suspensa fruit (Lianqiao).
IDPositive Mode (ESI+)Negative Mode (ESI−)FormulaNameStructureRelative Ion Intensity (×107)Ref.
Retention TimeExptl.
[M + H]+		Fragment IonsMass Error (ppm)Retention TimeExptl.
[M − H]−		Fragment IonsMass Error (ppm)WE
(+/−)		EE
(+/−)
1.1.03127.03889nd−0.635ndndndndC6H6O3benzene-1,2,4-triolPharmaceuticals 17 00740 i0011.03/ndnd/nd[13]
2.2.78268.10385136.0612−0.673ndndndndC10H13O4N5adenosinePharmaceuticals 17 00740 i0025.47/ndnd/nd[14]
3.3.14169.04961151.0385,
123.0436		0.4423.24167.03466123.0447,
108.0213		4.638C8H8O4vanillic acidPharmaceuticals 17 00740 i0031.06/7.542.34/nd[14]
4.3.55317.12292299.1143,
263.0929,
221.0820,
137.0603		−0.5493.72315.10797179.0567,
161.0459		1.669C14H20O8isomer of hydroxytyrosol glucosidePharmaceuticals 17 00740 i0044.58/2.46nd/nd[14]
5.3.82165.05450147.0434,
119.0486		−0.731ndndndndC9H8O3isomer of p-Coumaric acidPharmaceuticals 17 00740 i0057.52/ndnd/nd
6.ndndndnd4.34191.05573145.0500,
129.0552,
101.0602		3.745C7H12O6quinic acidPharmaceuticals 17 00740 i006nd/21.27nd/nd[13]
7.4.83155.07012137.0592,
109.0644		−0.972ndndndndC8H10O3halleridonePharmaceuticals 17 00740 i00738.28/ndnd/nd[13]
8.ndndndnd5.74153.01794109.0284−1.929C7H6O4protocatechuic acidPharmaceuticals 17 00740 i008nd/ndnd/0.50[15]
9.6.49317.12283299.1146,
281.1040		−0.833ndndndndC14H20O8isomer of hydroxytyrosol glucosidePharmaceuticals 17 00740 i0091.00/ndnd/nd[2]
10.ndndndnd7.89315.07126153.0197,
109.0295		0.640C13H16O9protocatechuic acid-O-glucopyranosidePharmaceuticals 17 00740 i010nd/0.76nd/nd[14]
11.9.40139.03885111.0436,
93.0694		−0.86710.15137.0240493.03425.251C7H6O3isomer of 3,4-dihydroxybenzaldehydePharmaceuticals 17 00740 i0116.44/11.09nd/nd[13]
12.9.97139.03783111.0433−8.2049.32137.02316120.8092,
103.4394		−1.172C7H6O3isomer of 3,4-dihydroxybenzaldehydePharmaceuticals 17 00740 i012nd/nd0.48/3.86[13]
13.10.45317.12305299.1147,
281.1026,
263.0923		−0.13910.28315.10757153.0561,
135.0455		0.400C14H20O8isomer of hydroxytyrosol glucosidePharmaceuticals 17 00740 i013nd/1.50nd/nd[14]
14.ndndndnd10.69353.08662191.0551,
179.0340		−0.251C16H18O9isomer of chlorogenic acidPharmaceuticals 17 00740 i014nd/0.34nd/nd[15]
15.ndndndnd11.20341.08682179.03390.327C15H18O9isomer of caffeic acid 3-glucosidePharmaceuticals 17 00740 i015nd/0.90nd/nd[14]
16.ndndndnd11.43375.12872213.0763,
125.0603		0.391C16H24O10loganic acidPharmaceuticals 17 00740 i016nd/5.36nd/3.21[14]
17.ndndndnd11.62389.10786345.1174,
183.0654		0.057C16H22O11secologanosidePharmaceuticals 17 00740 i017nd/4.81nd/0.30[14]
18.ndndndnd14.68487.14523469.1335,
427.1229,
397.1122,
233.0445,
203.0340,
179.0341		1.258C21H28O13cistanoside FPharmaceuticals 17 00740 i018nd/0.70nd/nd
19.14.40181.04939163.0387−0.80214.80179.03457135.04443.825C9H8O4isomer of caffeic acidPharmaceuticals 17 00740 i0194.05/6.43nd/0.77[13]
20.14.45463.18079317.1227,
301.1280		−0.45914.85461.16580315.1071,
205.0709,
135.0445		0.970C20H30O12forsythoside EPharmaceuticals 17 00740 i0202.62/0.869nd/0.74[14]
21.ndndndnd15.00353.08679191.05510.231C16H18O9isomer of chlorogenic acidPharmaceuticals 17 00740 i021nd/0.92nd/0.20[16]
22.ndndndnd17.73493.13428475.12330.461C23H26O12derhamnosyl suspensasidePharmaceuticals 17 00740 i022nd/0.43nd/nd[14]
23.ndndndnd17.75163.03867146.3310,
135.0436,
118.9913		−1.844C9H8O3isomer of p-coumaric acidPharmaceuticals 17 00740 i023nd/ndnd/0.16
24.18.20477.13864459.1276,
325.0911,
163.0387		−1.044ndndndndC23H24O11plantasiosidePharmaceuticals 17 00740 i02412.66/ndnd/nd[14]
25.18.43165.05457147.0435−0.30718.67163.03963119.04984.044C9H8O3isomer of p-coumaric acidPharmaceuticals 17 00740 i0251.91/0.185nd/0.22[15]
26.22.13625.21222607.2369,
589.2271		−0.76222.27623.19714461.1649,
443.1544		−0.150C29H36O15forsythoside HPharmaceuticals 17 00740 i0267.48/14.431.23/3.15[14]
27.ndndndnd23.14477.13669315.1053,
179.0331,
161.0226		−5.131C23H26O11calceolarioside APharmaceuticals 17 00740 i027nd/ndnd/1.03[14]
28.23.20625.21246479.1540,
471.1494,
325.0915		−0.379ndndndndC29H36O15forsythoside APharmaceuticals 17 00740 i0287.43/ndnd/nd[14]
29.23.40623.19672477.1382,
325.0912		−0.52423.22621.18140487.1441,
469.1337,
459.1494		0.005C29H34O15suspensaside APharmaceuticals 17 00740 i0291.08/1.80nd/nd[14]
30.ndndndnd24.49519.18640357.13280.601C26H32O11pinoresinol-4′-O-glucopyranosidePharmaceuticals 17 00740 i030nd/5.39nd/3.20[14]
31.24.80189.11209171.1012,
125.0957		−0.24124.67187.09706125.09673.071C9H16O4azelaic acidPharmaceuticals 17 00740 i0312.32/9.54nd/4.80[15]
32.25.89521.20148359.1483−0.49526.20519.18646357.13310.716C26H32O11epipinoresinol-4′-β-D-glucopyranosidePharmaceuticals 17 00740 i0320.37/4.070.19/3.96[14]
33.26.01375.14349357.1327−0.90526.12373.12838343.1174,
313.1071		0.538C20H22O7(+)-1-hydroxylpinoresinolPharmaceuticals 17 00740 i03311.87/6.694.25/2.13[14]
34.26.08359.14876341.1375,
223.0961,
137.0594		−0.431ndndndndC20H22O6isomer of pinoresinolPharmaceuticals 17 00740 i0346.16/nd2.16/nd[2]
35.29.23389.15921371.1485,
247.0963,
217.0858		−0.69329.52387.14408372.12020.647C21H24O7forsythialan BPharmaceuticals 17 00740 i03516.66/0.817.12/nd[2]
36.31.11335.22156317.2100,
289.2160		−0.376ndndndndC20H30O4isomer of dehydropinifolic acidPharmaceuticals 17 00740 i0362.54/nd2.65/nd[2]
37.31.49359.14883341.1378,
223.0962,
137.0595		−0.23631.46357.13330342.1093,
313.1433,
209.0810		0.098C20H22O6matairesinolPharmaceuticals 17 00740 i0373.44/1.790.54/0.59[14]
38.32.70359.14868341.1376,
311.1272,
235.0961,
217.0858		−0.654ndndndndC20H22O6isomer of pinoresinolPharmaceuticals 17 00740 i0381.07/nd2.92/nd[2]
39.32.78335.22141317.2107,
299.2003		−0.823ndndndndC20H30O4isomer of dehydropinifolic acidPharmaceuticals 17 00740 i0392.22/nd2.68/nd[2]
40.32.81359.14627341.1359,
235.0946		−7.364ndndndndC20H22O6isomer of pinoresinolPharmaceuticals 17 00740 i040nd/nd1.19/nd[2]
41.33.55335.22177317.2105,
299.2001,
289.2157		0.251ndndndndC20H30O4isomer of dehydropinifolic acidPharmaceuticals 17 00740 i0412.39/nd2.51/nd[2]
42.34.45335.22156317.2102,
299.1998,
287.1999		−0.376ndndndndC20H30O4isomer of dehydropinifolic acidPharmaceuticals 17 00740 i0421.05/nd3.33/nd[2]
Exptl. [M + H]+ represents the experimental m/z of a molecular ion in positive mode; Exptl. [M − H]− represents the experimental m/z of a molecular ion in negative mode. Ref: references; WE: water extracts of Lianqiao; EE: ethanol extracts of Lianqiao; nd not detectable.
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Gao, B.; Zhu, H.; Liu, Z.; He, X.; Sun, J.; Li, Y.; Wu, X.; Pehrsson, P.; Zhang, Y.; Yao, Y.; et al. Chemical Compositions of Lianqiao (Forsythia suspensa) Extracts and Their Potential Health Benefits. Pharmaceuticals 2024, 17, 740. https://doi.org/10.3390/ph17060740

AMA Style

Gao B, Zhu H, Liu Z, He X, Sun J, Li Y, Wu X, Pehrsson P, Zhang Y, Yao Y, et al. Chemical Compositions of Lianqiao (Forsythia suspensa) Extracts and Their Potential Health Benefits. Pharmaceuticals. 2024; 17(6):740. https://doi.org/10.3390/ph17060740

Chicago/Turabian Style

Gao, Boyan, Hanshu Zhu, Zhihao Liu, Xiaohua He, Jianghao Sun, Yanfang Li, Xianli Wu, Pamela Pehrsson, Yaqiong Zhang, Yuanhang Yao, and et al. 2024. "Chemical Compositions of Lianqiao (Forsythia suspensa) Extracts and Their Potential Health Benefits" Pharmaceuticals 17, no. 6: 740. https://doi.org/10.3390/ph17060740

APA Style

Gao, B., Zhu, H., Liu, Z., He, X., Sun, J., Li, Y., Wu, X., Pehrsson, P., Zhang, Y., Yao, Y., & Yu, L. (2024). Chemical Compositions of Lianqiao (Forsythia suspensa) Extracts and Their Potential Health Benefits. Pharmaceuticals, 17(6), 740. https://doi.org/10.3390/ph17060740

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop