Flavonoids isolated from Lespedeza cuneata G. Don and their inhibitory effects on nitric oxide production in lipopolysaccharide-stimulated BV-2 microglia cells

A Single-Center, Randomized, Double-Blind, and Placebo-Controlled Comparative Human Study to Verify the Functionality and Safety of the Lespedeza cuneata G. Don Extract for the Improvement of Aging Male Syndrome

OBJECTIVE

Aging male syndrome is a clinical biochemical syndrome characterized by typical aging symptoms and serum testosterone deficiency. Although it is accompanied by various health problems, directly affects life satisfaction, and requires proper management, no clear prevention or treatment other than hormone replacement therapy is currently available for this syndrome. Here, we aimed to determine the efficacy and safety of the Lespedeza cuneata extract in the management of the aging male syndrome.

METHODS

Males aged 43-70 years who provided consent for participation and had a total Aging Males' Symptom questionnaire score ≥ 37 and testosterone level ≤ 500 ng/dL were enrolled in this study. This study was conducted in a randomized, double-blind manner. Participants were randomly assigned to either the experimental or control groups and orally administered the assigned product twice a day. Efficacy was evaluated by measuring changes in Aging Males' Symptom score, Androgen Deficiency in the Aging Male questionnaire score, International Index of Erectile Function score, International Prostatic Symptom Score, blood test results, and body mass index at 8 weeks.

RESULTS

After 8 weeks, the experimental group had significantly improved symptom scores compared to the control group on the Aging Males' Symptom and Androgen Deficiency in the Aging Male questionnaires. However, no significant differences in the International Index of Erectile Function score, International Prostatic Symptom Score score, blood test results, and body mass index were observed between the experimental and control groups.

CONCLUSION

Lespedeza cuneata extract safely alleviates andropause symptoms without any significant side effects, suggesting its potential for the treatment of the aging male syndrome.

Phytochemical profiling, in vitro antioxidants, and antidiabetic efficacy of ethyl acetate fraction of Lespedeza cuneata on streptozotocin-induced diabetic rats

In the recent past, phytomolecules are exponentially applied in discovering the antidiabetic drug due to less adverse effects. This work screened the active solvent fraction of Lespedeza cuneata based on the phytochemical, enzyme inhibition, and antioxidant properties. The antioxidant efficacy of the different fractions of the L. cuneata was assessed by 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), ferric reducing power, hydrogen peroxide, and hydroxyl radical scavenging assays. The digestive enzyme (α-amylase and α-glucosidase) inhibitory activity was also evaluated. The phytochemical composition of ethyl acetate fraction of L. cuneata (Lc-EAF) was studied by UHPLC-QTOF-MS/MS. The effect of Lc-EAF treatments on glucose uptake was studied in insulin resistance HepG2 cells (IR-HepG2). Further, the antidiabetic effect of Lc-EAF in streptozotocin (STZ)-induced diabetic mice were demonstrated. Ethyl acetate, hexane, and methanol fractions of the L. cuneata showed notable antioxidant, α-amylase, and α-glucosidase inhibitory properties. Among the fractions, Lc-EAF was found to be the most potent. The Lc-EAF exhibited an IC₅₀ of 205.32 ± 23.47 µg/mL and 105.32 ± 13.93 µg/mL for α-amylase and α-glucosidase inhibition, respectively. In addition, 75 µg/mL of Lc-EAF exposure enhanced glucose uptake (68.23%) in IR-HepG2 cells. In vivo study indicated that treatment of Lc-EAF (100 mg/kg b.wt) maintained the blood glucose level through reduced insulin level while improving the lipid profile, hepatic, and renal markers. These findings suggest that Lc-EAF could be considered a prominent source for antidiabetic, anti-hyperlipidemic, and anti-ROS potentials.

Flavonoids regulate tumor-associated macrophages - From structure-activity relationship to clinical potential (Review)

In recent years, the strategy for tumor therapy has changed from focusing on the direct killing effect of different types of therapeutic agents on cancer cells to the new mainstream of multi-mode and -pathway combined interventions in the microenvironment of the developing tumor. Flavonoids, with unique tricyclic structures, have diverse and extensive immunomodulatory and anti-cancer activities in the tumor microenvironment (TME). Tumor-associated macrophages (TAMs) are the most abundant immunosuppressive cells in the TME. The regulation of macrophages to fight cancer is a promising immunotherapeutic strategy. This study covers the most comprehensive cognition of flavonoids in regulating TAMs so far. Far more than a simple list of studies, we try to dig out evidence of crosstalk at the molecular level between flavonoids and TAMs from literature, in order to discuss the most relevant chemical structure and its possible relationship with the multimodal pharmacological activity, as well as systematically build a structure-activity relationship between flavonoids and TAMs. Additionally, we point out the advantages of the macro-control of flavonoids in the TME and discuss the potential clinical implications as well as areas for future research of flavonoids in regulating TAMs. These results will provide hopeful directions for the research of antitumor drugs, while providing new ideas for the pharmaceutical industry to develop more effective forms of flavonoids.

Biologically active polyphenolic compounds from Lespedeza bicolor

We investigated the ability of six prenylated prerocarpans, stilbenoid, and a new dimeric flavonoid, lespebicolin B, from stem bark as well as two 3-O-rutinosides and a mixture of 3-O-β-D-glucosides of quercetin and kaempferol from flowers of Lespedeza bicolor to inhibit HSV-1 replication in Vero cells. Pretreatment of HSV-1 with polyphenolic compounds (direct virucidal effect) showed that pterocarpans lespedezol A₂ (1), (6aR,11aR)-6a,11a-dihydrolespedezol A₂ (2), (6aR,11aR)-2-isoprenyldihydrolespedezol A₂ (4), and (6aR,11aR,3'R)-dihydrolespedezol A₃ (5) significantly inhibited viral replication, with a selective index (SI) ≥10. Compound 4 possessed the lowest 50% - inhibiting concentration (IC₅₀) and the highest SI values (2.6 μM and 27.9, respectively) in this test. (6aR,11aR)-2-Isoprenyldihydrolespedezol A₂ (4) also had a moderate effect under simultaneous treatment of Vero cells with the tested compound and virus (IC₅₀ and SI values were 5.86 μM and 12.4, respectively). 3-O-rutinosides of quercetin and kaempferol and a mixture of 3-O-β-D-glucosides of quercetin and kaempferol (10 and 12) also showed significant virucidal activity, with SI values of 12.5, 14.6, and 98.2, respectively, and IC₅₀ values of 8.6, 12.2, and 3.6, respectively. We also performed a quantitative structure-activity relationship (QSAR) analysis of data on the virucidal activity of polyphenolics with 4 < pIC₅₀ < 6. It was found that the virucidal activity of these compounds depended on both the structure of the aromatic part and the conformation of geranyl and isoprenyl side chains of their molecules. These findings are correlated with the largest value of the principal moment of inertia (pmi) descriptor describing the geometry of molecules.

Phytochemical Constituents Identified from the Aerial Parts of Lespedeza cuneata and Their Effects on Lipid Metabolism during Adipocyte Maturation

Lespedeza cuneata, belonging to Fabaceae, is well-known as Chinese bushclover, and it has been used in traditional folk medicines for the treatment of disorders, such as diabetes, hematuria, and insomnia. As part of continuing research projects to discover interesting natural compounds with biological activities from Korean medicinal plants, the phytochemical investigation of L. cuneata resulted in the isolation of five chemical constituents: α-tocopherol (1), 7a-methoxy-α-tocopherol (2), 13(R)-hydroxy-octadeca-(9Z,11E,15Z)-trien-oic acid (3), α-dimorphecolic acid (4), and lupeol (5). The structural determination of the isolated compounds was elucidated from data gathered through nuclear magnetic resonance (NMR) spectroscopy and liquid chromatography–mass spectrometry (LC/MS). Until now, this study is the first to report these five compounds from the plant L. cuneata. Moreover, these isolated compounds (1–5) were evaluated for their anti-adipogenesis effects and their role in lipid metabolism during adipocyte maturation. As a result, the upregulation of mRNA expression levels of Fabp4 from 3T3-L1 pre-adipocytes treated with compounds 3 and 4 demonstrated that these compounds efficiently induced adipocyte differentiation. Furthermore, compounds 3 and 4 were found to regulate lipid metabolism by the induction of lipolytic and of lipogenic gene expressions. Therefore, experimental data from these findings supported that the compounds 3 and 4 induce the adipogenesis of 3T3-L1 pre-adipocytes and regulate lipid metabolism.

1-Methoxylespeflorin G11 Protects HT22 Cells from Glutamate-Induced Cell Death through Inhibition of ROS Production and Apoptosis

This study aimed to investigate the neuroprotective effects of 1-methoxylespeflorin G11 (MLG), a pterocarpan, against glutamate-induced neurotoxicity in neuronal HT22 hippocampal cells. The protective effects of MLG were evaluated using MTT assay and microscopic analysis. The extent of apoptosis was studied using flow cytometric analysis performed on the damaged cells probed with annexin V/propidium iodide. Moreover, mitochondrial reactive oxygen species (ROS) were assessed using flow cytometry through MitoSOXTM Red staining. To determine mitochondrial membrane potential, staining with tetramethylrhodamine and JC-1 was performed followed by flow cytometry. The results demonstrated that MLG attenuates glutamate-induced apoptosis in HT22 cells by inhibiting intracellular ROS generation and mitochondrial dysfunction. Additionally, MLG prevented glutamate-induced apoptotic pathway in HT22 cells through upregulation of Bcl-2 and downregulation of cleaved PARP-1, AIF, and phosphorylated MAPK cascades. In addition, MLG treatment induced HO-1 expression in HT22 cells. These results suggested that MLG exhibits neuroprotective effects against glutamate-induced neurotoxicity in neuronal HT22 cells by inhibiting oxidative stress and apoptosis.

Protective Role of Natural Products in Glioblastoma Multiforme: A Focus on Nitric Oxide Pathway

In spite of therapeutic modalities such as surgical resection, chemotherapy, and radiotherapy, Glioblastoma Multiforme (GBM) remains an incurable fatal disease. This necessitates further therapeutic options that could enhance the efficacy of existing modalities. Nitric Oxide (NO), a short-lived small molecule, has been revealed to play a crucial role in the pathophysiology of GBM. Several studies have demonstrated that NO is involved in apoptosis, metastasis, cellular proliferation, angiogenesis, invasion, and many other processes implicated in GBM pathobiology. Herein, we elaborate on the role of NO as a therapeutic target in GBM and discuss some natural products affecting the NO signaling pathway.

Aviculin Isolated from Lespedeza cuneata Induce Apoptosis in Breast Cancer Cells through Mitochondria-Mediated Caspase Activation Pathway

The global incidence of breast cancer has increased. However, there are many impediments to the development of safe and effective anticancer drugs. The aim of the present study was to evaluate the effect of aviculin isolated from Lespedeza cuneata (Dum. Cours.) G. Don. (Fabaceae) on MCF-7 human breast cancer cells and determine the underlying mechanism. Using the bioassay-guided isolation by water soluble tetrazolium salt (WST-1)-based Ez-Cytox assay, nine compounds (four lignan glycosides (1-4), three flavonoid glycosides (5-7), and two phenolic compounds (8 and 9)) were isolated from the ethyl acetate (EA) fraction of the L. cuneata methanolic extract. Of these, aviculin (2), a lignan glycoside, was the only compound that reduced metabolic activity on MCF-7 cells below 50% (IC₅₀: 75.47 ± 2.23 μM). The underlying mechanism was analyzed using the annexin V Alexa Fluor 488 binding assay and Western blotting. Aviculin (2) was found to induce apoptotic cell death through the intrinsic apoptosis pathway, as indicated by the increased expression of initiator caspase-9, executioner caspase-7, and poly (ADP-ribose) polymerase (PARP). Aviculin (2)-induced apoptotic cell death was accompanied by an increase in the Bax/Bcl-2 ratio. These findings demonstrated that aviculin (2) could induce breast cancer cell apoptosis through the intrinsic apoptosis pathway, and it can therefore be considered an excellent candidate for herbal treatment of breast cancer.

Three new compounds with nitric oxide inhibitory activity from Tirpitzia sinensis, an ethnomedicinal plant from Southwest China

The medicinal plant Tirpitzia sinensis has been used by the Zhuang ethnic people in mountainous areas of Southwest China to stop bleeding, invigorate blood circulation, and treat inflammation and wounds. In order to further explore its traditional medicinal uses, the phytochemical constituents of this species were examined. Three new compounds, the lignan tirpitzin (1), the flavonoid tirpitzoside (2), and the furan-glycoside tirpitziol (3), along with five known compounds were isolated from the aerial part of T. sinensis for the first time. The structures of these compounds were elucidated by 1D and 2D NMR, LC/MS, IR spectrometric methods and compared with published data. The results of an in silico pharmacophore-based analysis showed potential targets of the new compounds, including ERBB2, IRAK4, LCK, JAK2, MAPK14, and MMP-12. These targets suggested that 1-3 may be involved with wound-healing and/or inflammation, leading to an in vitro assay of nitric oxide (NO) inhibition assays with lipopolysaccharide-induced BV-2 cells. All three new compounds displayed moderate NO inhibitory activity with the IC₅₀ values of 14.97 ± 0.87, 26.63 ± 1.32, and 17.09 ± 2.3 μM, respectively.

Lespedeza cuneata protects the endothelial dysfunction via eNOS phosphorylation of PI3K/Akt signaling pathway in HUVECs

BACKGROUND

Lespedeza cuneata G.Don (LCE), which belongs to the genus Lespedeza (Leguminosae), is a traditional oriental medicine known to prevent diabetes and cardiovascular diseases. However, no scientific studies about the effectiveness of LCE, their responsible bioactive constituents, and its mechanisms against endothelial dysfunction have been performed.

PURPOSE

This study was performed to investigate the role of LCE and its chemical components in ameliorating endothelial dysfunction.

METHODS

The production of nitric oxide (NO) was evaluated after LCE treatment in HUVECs. Cell viability was measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reagent. Western blot analysis was performed to determine the protein expression of endothelial nitric oxide synthase (eNOS) and protein kinase B (PKB, also known as Akt) in human umbilical vein endothelial cells (HUVECs).

RESULTS

Pretreatment with L-NAME and LY294002 significantly decreased the LCE-induced NO production, as well as eNOS and Akt phosphorylation. β-Sitosterol and β-Sitosterol 6'-linolenoyl-3-O-β-D-glucopyranoside are the bioactive constituents increase NO production as well as eNOS phosphorylation.

CONCLUSION

Our findings suggest that LCE increase NO production via eNOS phosphorylation of PI3K/Akt signaling pathway.

Lignan Glycosides and Flavonoid Glycosides from the Aerial Portion of Lespedeza cuneata and Their Biological Evaluations

Lespedeza cuneata (Fabaceae), known as Chinese bushclover, has been used in traditional medicines for the treatment of diseases including diabetes, hematuria, and insomnia. As part of a continuing search for bioactive constituents from Korean medicinal plant sources, phytochemical analysis of the aerial portion of L. cuneata led to the isolation of two new lignan glycosides (1,2) along with three known lignan glycosides (3–7) and nine known flavonoid glycosides (8–14). Numerous analysis techniques, including 1D and 2D NMR spectroscopy, CD spectroscopy, HR-MS, and chemical reactions, were utilized for structural elucidation of the new compounds (1,2). The isolated compounds were evaluated for their applicability in medicinal use using cell-based assays. Compounds 1 and 4–6 exhibited weak cytotoxicity against four human breast cancer cell lines (Bt549, MCF7, MDA-MB-231, and HCC70) (IC₅₀ < 30.0 μM). However, none of the isolated compounds showed significant antiviral activity against PR8, HRV1B, or CVB3. In addition, compound 10 produced fewer lipid droplets in Oil Red O staining of mouse mesenchymal stem cells compared to the untreated negative control without altering the amount of alkaline phosphatase staining.

Antiwrinkle and antimelanogenesis activity of the ethanol extracts of Lespedeza cuneata G. Don for development of the cosmeceutical ingredients

To develop the ingredient with the cosmeceutical function, the antiwrinkle and antimelanogenesis effects of the ethanol extract of Lespedeza cuneata G. Don were investigated. DPPH radical scavenging activity was significantly increased with the extract of L. cuneata G. Don. Cell viability on CCD986Sk human fibroblast was also increased by the ethanol extract of L. cuneata G. Don. The inhibitory function of the extract of L. cuneata G. Don on collagenase, elastase, and tyrosinase was evaluated. Protein expression level of Claudin-1, Occludin, and ZO-1 was up-regulated in HaCaT human keratinocyte by the extract of L. cuneata G. Don. In addition, the extract of L. cuneata G. Don inhibited melanin synthesis in B16F10 murine melanoma cells by decreasing MITF, TRP1, and TRP2 protein levels and increasing the phosphorylated Erk and Akt. Thus, these findings would be useful for developing the new cosmeceutical formulations based on the extract of L. cuneata G. Don.

Juglanin suppresses fibrosis and inflammation response caused by LPS in acute lung injury

Acute lung injury in children is a complication showing devastating disorders linked to fibrosis progression and inflammation response. Fibrosis and inflammation response are two markers for acute lung injury. Juglanin is a natural product mainly isolated from green walnut husks of Juglans mandshurica, which isconsidered as the functional composition among a series of compounds. It exhibited effective role in various diseases by inhibiting inflammation response. In our study, the protective effects and anti-inflammatory activity of juglanin were investigated in mice and lung cells treated by lipopolysaccharide (LPS) to reveal the possible mechanism by which juglanin attenuates acute lung injury. The mice were separated into four groups. The mouse model was established with 15 mg/kg LPS injection. Juglanin dramatically reduced the inflammation of cell infiltration. Compared to mice only treated with LPS, LPS-treated mice in the presence of juglanin developed less lung fibrosis with lower levels of α-smooth muscle-actin (α-SMA), collagen type I, collagen type III, and transforming growth factor-β1 (TGF-β1). Additionally, juglanin markedly downregulated inflammatory cytokine secretion and phosphorylated nuclear factor-κB (NF-κB) expression via inhibiting IKKα/IκBα signaling pathway. Our results indicate that juglanin has a protective role in LPS-triggered acute lung injury via suppression of fibrosis and inflammation response by NF-κB signaling pathways inactivation. Thus, juglanin may be a potential candidate as dietary supplement for acute lung injury for children in future.

Ultrasonicated Lespedeza cuneata extract prevents TNF-α-induced early atherosclerosis in vitro and in vivo

This study evaluated the use of ultrasonication to extract Lespedeza cuneata as a potential nutraceutical for preventing vascular inflammation.

Lespedeza bicolor ameliorates endothelial dysfunction induced by methylglyoxal glucotoxicity

BACKGROUND

Lespedeza species have been used as a traditional medicine to treat nephritis, azotemia, inflammation, energy depletion, diabetes, and diuresis.

PURPOSE

The purpose of this study is to screen the most potent Lespedeza species against methylglyoxal (MGO)-induced glucotoxicity, and to elucidate the mechanisms of action. Also, we will attempt to identify small chemical metabolites that might be responsible for such anti-glucotoxicity effects.

METHODS

Firstly, the protective effect of 26 different Lespedeza species against MGO-induced toxicity in human umbilical vein endothelial cells was investigated. The chemical metabolites of the most potent species (Lespedeza bicolor 1 (LB1) were identified by high pressure liquid chromatography quadrupole time-of-flight tandem mass spectrometry (HPLC-Q-TOF-MS/MS), then quantified by HPLC. The effects of LB1 on MGO-induced apoptosis were measured by annexin V-FITC staining and western blot. Inhibitory effects of LB1 on MGO-induced ROS generation, and effect of LB1 on advanced glycation end products (AGEs) inhibitor or a glycated cross-link breaker are also measured.

RESULTS

Among different Lespedeza species, LB1 extract was shown to reduce intracellular reactive oxidative species, exhibit anti-apoptotic effects, strongly inhibit all the mitogen-activated protein kinase signals, inhibit MGO-induced AGEs formation, and break down preformed AGEs. We tentatively identified 17 chemical constituents of LB1 by HPLC-Q-TOF-MS/MS. Among those, some components, such as genistein and quercetin, significantly reduced the AGEs formation and increased the AGEs-breaking activity, resulting in the reduction of glucotoxicity.

CONCLUSION

LB1 extract has shown to be effective in preventing or treating MGO-induced endothelial dysfunction.

(-)-9'-O-(α-l-Rhamnopyranosyl)lyoniresinol from Lespedeza cuneata suppresses ovarian cancer cell proliferation through induction of apoptosis

Lespedeza cuneata (Dum. Cours.) G. Don. (Fabaceae), known as Chinese bushclover or sericea lespedeza, has been used in traditional medicine to treat diabetes, hematuria, and insomnia, and it has been reported that bioactive compounds from L. cuneata possess various pharmacological properties. However, there has been no study to determine the active compounds from L. cuneata with potential activity against ovarian cancer. This study aimed to isolate cytotoxic compounds from L. cuneata and identify the molecular mechanisms underlying the apoptosis pathway in ovarian cancer cells. Based on cytotoxic activity identified in the screening test, chemical investigation of the active fraction of L. cuneata led to the isolation of nine compounds including four lignanosides (1-4), three flavonoid glycosides (5-7), and two phenolics (8-9). Cytotoxicity and the molecular mechanism were examined by methyl thiazolyl tetrazolium (MTT) assay and Western blot analysis. Of the isolated compounds, (-)-9'-O-(α-l-rhamnopyranosyl)lyoniresinol (3) demonstrated the strongest effect in suppressing A2780 human ovarian carcinoma cell proliferation in a dose-dependent manner, with an IC₅₀ value of 35.40 ± 2.78 μM. Control A2780 cells had normal morphology, whereas cell blebbing, shrinkage, and condensation were observed after treatment with compound 3. Western blotting analysis showed that compound 3 inhibited A2780 human ovarian cancer cell viability by activating caspase-8, caspase-3, and PARP, which contributed to apoptotic cell death. These results suggest that (-)-9'-O-(α-l-rhamnopyranosyl)lyoniresinol (3) has potent anticancer activities against A2780 human ovarian carcinoma cells through the extrinsic apoptotic pathway. Therefore, (-)-9'-O-(α-l-rhamnopyranosyl)lyoniresinol is an excellent candidate for the development of novel chemotherapeutics.

The flavonoid rutin modulates microglial/macrophage activation to a CD150/CD206 M2 phenotype

Rutin is a glycosylated flavonoid present in many fruits and plants that has been demonstrated to have anti-inflammatory and antioxidant properties. However, little is known about the mechanisms underlying microglial activation and its effects on the regulation of cytokines and chemokines associated with inflammatory responses in the central nervous system. In this study we examined the effect of rutin on resting or lipopolysaccharide (LPS)-stimulated microglia and characterized their modulation to an activated M1 phenotype or an alternatively activated M2 phenotype. Microglial cells were treated with rutin (1-100 μM); alternatively, microglial cells were stimulated with LPS and the cells were then treated with rutin (50 μM). The results revealed that rutin treatment was not toxic to microglial cells and induced a dose-dependent increase in microglial proliferation associated with changes in morphology after 24 h of treatment. Rutin also induced microglial activation characterized by an increase in OX-42 positive cells and a large proportion of cells with a CD150/CD206-positive M2 phenotype. Rutin also induced a decrease in the mRNA levels of TNF, IL1β, IL6 and iNOS, reduced the production of IL6, TNF, and nitric oxide, and increased production of the M2 regulatory cytokine IL10 and arginase. Rutin also significantly inhibited the LPS-induced expression of PTGS2, IL18 and TGFβ mRNA. These findings show that rutin has the ability to promote microglial proliferation and induces microglial polarization to the M2 profile when cells are stimulated with LPS. These results point this flavonoid as a possible alternative in the treatment or prevention of neurodegenerative disorders.