Total flavonoids from Astragalus alleviate endothelial dysfunction by activating the Akt/eNOS pathway

Molecular Mechanisms of Plant Extracts in Protecting Aging Blood Vessels

Plant Extracts (PE) are natural substances extracted from plants, rich in various bioactive components. Exploring the molecular mechanisms and interactions involved in the vascular protective effects of PE is beneficial for the development of further strategies to protect aging blood vessels. For this review, the content was obtained from scientific databases such as PubMed, China National Knowledge Infrastructure (CNKI), and Google Scholar up to July 2024, using the search terms "Plant extracts", "oxidative stress", "vascular aging", "endothelial dysfunction", "ROS", and "inflammation". This review highlighted the effects of PE in protecting aging blood vessels. Through pathways such as scavenging reactive oxygen species, activating antioxidant signaling pathways, enhancing respiratory chain complex activity, inhibiting mitochondrial-reactive oxygen species generation, improving nitric oxide bioavailability, downregulating the secretion of inflammatory factors, and activating sirtuins 1 and Nrf2 signaling pathways, it can improve vascular structural and functional changes caused by age-related oxidative stress, mitochondrial dysfunction, and inflammation due to aging, thereby reducing the incidence of age-related cardiovascular diseases.

Flavonoids: Potential therapeutic agents for cardiovascular disease

Flavonoids are found in the roots, stems, leaves, and fruits of many plant taxa. They are related to plant growth and development, pigment formation, and protection against environmental stress. Flavonoids function as antioxidants and exert anti-inflammatory effects in the cardiovascular system by modulating classical inflammatory response pathways, such as the TLR4-NF-ĸB, PI3K-AKT, and Nrf2/HO-1 signalling pathways. There is increasing evidence for the therapeutic effects of flavonoids on hypertension, atherosclerosis, and other diseases. The potential clinical value of flavonoids for diseases of the cardiovascular system has been widely explored. For example, studies have evaluated the roles of flavonoids in the regulation of blood pressure via endothelium-dependent and non-endothelium-dependent pathways and in the regulation of myocardial systolic and diastolic functions by influencing calcium homeostasis and smooth muscle-related protein expression. Flavonoids also have hypoglycaemic, hypolipidemic, anti-platelet, autophagy, and antibacterial effects. In this paper, the role and mechanism of flavonoids in cardiovascular diseases were reviewed in order to provide reference for the clinical application of flavonoids in the future.

Total flavonoids of Astragalus protects glomerular filtration barrier in diabetic kidney disease

BACKGROUND

Diabetic kidney disease (DKD) is a prevalent complication of diabetes and the leading cause of end-stage renal disease. Recent evidence suggests that total flavonoids of Astragalus (TFA) has promising effects on diabetes; however, its influence on DKD and the underlying mechanism remains unclear.

METHODS

In this study, we induced the DKD model using streptozotocin (STZ) in male C57BL/6J mice and utilized glomerular endothelial cell (GEC) lines for in vitro investigations. We constructed a network pharmacology analysis to understand the mechanism of TFA in DKD. The mechanism of TFA action on DKD was investigated through Western blot analysis and multi-immunological methods.

RESULTS

Our findings revealed that TFA significantly reduced levels of urinary albumin (ALB). Network pharmacology and intracellular pathway experiments indicated the crucial involvement of the PI3K/AKT signaling pathway in mediating these effects. In vitro experiments showed that TFA can preserve the integrity of the glomerular filtration barrier by inhibiting the expression of inflammatory factors TNF-alpha and IL-8, reducing oxidative stress.

CONCLUSION

Our findings demonstrated that TFA can ameliorates the progression of DKD by ameliorating renal fibrosis and preserving the integrity of the kidney filtration barrier. These results provide pharmacological evidence supporting the use of TFA in the treatment of kidney diseases.

An integrated strategy to evaluate active substances of Astragali Radix-Carthami Flos combination on the treatment of cerebral ischemia reperfusion injury based on TQSM polypharmacokinetics and pharmacodynamics

As a classic herb pair, Astragali Radix-Carthami Flos (AR-CF) has revealed good biological activity in the treatment of cerebral ischemia/reperfusion injury (CI/RI), which remained to be further clarified together with the underlying efficacy related compounds for material basis. In this study, the nine formulations were obtained by L9 (34) orthogonal array design of four active fractions (saponin and flavonoid extracted from AR, safflower yellow and safflower red extracted from CF). The concentrations of eleven components and the levels of four biochemical indicators in rat plasma were continuously detected after intragastric administration of nine formulations, respectively. The collected data were analyzed by sigmoid-Emax function to understand the polypharmacokinetics and pharmacodynamics (PK-PD) behaviors of multi-components. Using the total quantum statistic moment polypharmacokinetics and its similarity method, the importance of four active fractions from AR-CF in relieving CI/RI was discussed and the Q-markers were screened. The results represented that a reliable and robust liquid chromatography tandem mass spectrometry method been successfully established to simultaneously determine the concentrations of eleven components in rat plasma. The AUC and MRT values of components from flavonoid fraction had the greatest contribution to AUCT and MRTT values. The transitivity in vivo of calycosin-7-O-β-Dglucoside (CG), astragaloside IV (AIV) and hydroxysafflor yellow A (HYA) was closer to polypharmacokinetics behavior. All formulations up/down-regulated the levels of GSH-Px and ATP/ET and LDH to varying degrees, among which formulation 7 had the best regulating effect. By drawing the time-concentration-effect curve, clockwise hysteresis loops were presented in the time-concentration-effect relationships between eleven components and LDH/ET, while the relationship between eleven components and ATP/GSH-Px expressed as anticlockwise hysteresis loops. In conclusion, the combination based on the combination principle of formulation 7 produced the best alleviation effect on CI/RI, and flavonoid fraction might played key role in this process. The CG, AIV and HYA were identified as Q-markers. This research offered a novel strategy for exploring the active substances, and provided further understanding regarding the development of drugs for the treatment of cerebral ischemia-reperfusion injury.

Total flavonoids of astragalus attenuates experimental autoimmune encephalomyelitis by suppressing the activation and inflammatory responses of microglia via JNK/AKT/NFκB signaling pathway

BACKGROUND

Microglia-mediated neuroinflammation is one of the most prominent characteristics of multiple sclerosis (MS), a chronic demyelination disease. As one of the main active ingredients in Astragali radix, total flavonoids of Astragalus (TFA) has multiple pharmacological effects such as immunomodulation, anti-inflammation and and anti-tumor. However, little is known about whether TFA could inhibit microglia-mediated neuroinflammation in MS.

PURPOSE

This study was aimed to elucidate whether TFA could inhibit microglia-mediated neuroinflammation in MS.

STUDY DESIGN

In the present study, we explored the protective effect of TFA on experimental autoimmune encephalomyelitis (EAE), an animal model of MS, in mice for the first time, and discussed its mechanism from the aspect of anti-microglia-mediated neuroinflammation.

METHODS

The mice received oral administration of TFA (25 and 50 mg/kg) daily from two days before immunization and continued until day 21 post-immunization. The effect of TFA on EAE in mice and its mechanism were investigated by ELISA, Western blot, real-time PCR, luciferase reporter assay, histopathology and immunohistochemistry.

RESULTS

TFA were shown to alleviate the severity of EAE in mice. It inhibited the excessive activation of microglia both in spinal cords of EAE mice and in LPS-stimulated BV-2 cells, evidenced by weakening the production of inflammatory mediators such as NO, TNF-α, IL-6, and IL-1β markedly at either protein or mRNA level. Further study demonstrated that TFA repressed the phosphorylation, nuclear translocation and transcriptional activity of NFκB, and inhibited the activation of AKT and JNK signaling in BV-2 cells induced by LPS. The agonists of AKT and JNK, anisomycin and SC79, could partly abolish the inhibitory effect of TFA on the production of inflammatory mediators in BV-2 cells induced by LPS.

CONCLUSIONS

Taken together, our results clarified that TFA inhibited microglia-mediated inflammation in EAE mice probably through deactivating JNK/AKT/NFκB signaling pathways. The novel findings may lay a theoretical foundation for the clinical application of TFA in the treatment of MS.

Epigallocatechin Gallate Reduces Homocysteine-Caused Oxidative Damages through Modulation SIRT1/AMPK Pathway in Endothelial Cells

Elevated plasma concentration of total homocysteine is a pathological condition that causes vascular endothelial injury and subsequently leads to the progression of endothelial apoptosis in atherosclerosis. Epigallocatechin gallate (EGCG), a well-known anti-oxidant in green tea, has been reported with benefits on metabolic and cardiovascular diseases. This study aimed to explore that EGCG ameliorates homocysteine-induced endothelial cell apoptosis through enhancing the sirtuin 1 (SIRT1)/AMP-activated protein kinase (AMPK) survival signaling pathway. Human umbilical endothelial cells were treated with homocysteine in the presence or absence of EGCG. We found that EGCG significantly increased the activities of SIRT1 and AMPK. EGCG diminished homocysteine-mediated nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activation by inhibiting protein kinase C activation as well as reactive oxygen species (ROS) generation and recovered the activity of the endogenous antioxidant enzyme, superoxidase dismutase (SOD). Besides, EGCG also restores homocysteine-mediated dephosphorylation of Akt and decreases endothelial NO synthase (eNOS) expression. Furthermore, EGCG ameliorates homocysteine-activated pro-apoptotic events. The present study shows that EGCG prevents homocysteine-induced endothelial cell apoptosis via enhancing SIRT1/AMPK as well as Akt/eNOS signaling pathways. Results from this study indicated that EGCG might have some benefits for hyperhomocysteinemia.

Exploring the In Vivo Existence Forms (23 Original Constituents and 147 Metabolites) of Astragali Radix Total Flavonoids and Their Distributions in Rats Using HPLC-DAD-ESI-IT-TOF-MSn

Astragali Radix total flavonoids (ARTF) is one of the main bioactive components of Astragali Radix (AR), and has many pharmacological effects. However, its metabolism and effective forms remains unclear. The HPLC-DAD-ESI-IT-TOF-MSⁿ technique was used to screen and tentatively identify the in vivo original constituents and metabolites of ARTF and to clarify their distribution in rats after oral administration. In addition, modern chromatographic methods were used to isolate the main metabolites from rat urine and NMR spectroscopy was used to elucidate their structures. As a result, 170 compounds (23 original constituents and 147 metabolites) were tentatively identified as forms existing in vivo, 13 of which have the same pharmacological effect with ARTF. Among 170 compounds, three were newly detected original constituents in vivo and 89 were new metabolites of ARTF, from which 12 metabolites were regarded as new compounds. Nineteen original constituents and 65 metabolites were detected in 10 organs. Four metabolites were isolated and identified from rat urine, including a new compound (calycoisn-3'-O-glucuronide methyl ester), a firstly-isolated metabolite (astraisoflavan-7-O-glucoside-2'-O-glucuronide), and two known metabolites (daidzein-7-O-sulfate and calycosin-3'-O-glucuronide). The original constituents and metabolites existing in vivo may be material basis for ARTF efficacy, and these findings are helpful for further clarifying the effective forms of ARTF.

Total flavonoids suppress lung cancer growth via the COX-2-mediated Wnt/β-catenin signaling pathway

The aim of the present study was to explore the anti-cancer effects of total flavonoids (TF) on lung cancer and to investigate the underlying mechanism. The inhibitory effect of TF on the proliferation of A549 cells in vitro was measured using an MTT assay. The apoptotic rate of TF-treated A549 cells was analyzed using flow cytometry and terminal deoxynucleotidyl transferase-mediated biotinylated UTP nick end labeling. Migration and invasion assays were performed to investigate the anti-migration effect of TF on A549 cells. Reverse-transcription quantitative PCR was used to analyze BCL2-like 2, BCL2, Bax, Bad, cyclooxygenase 2 (COX-2), Wnt and β-catenin mRNA expression levels in A549 cells. The in vivo anti-cancer effect of TF was investigated in a subcutaneous xenograft model of lung cancer in BALB/c nude mice. The results obtained in the present study revealed that TF exerted a significant inhibitory effect on the proliferation of A549 cells in a dose-dependent manner (P<0.01). TF induced apoptosis of A549 cells, which exhibited increased and decreased expression of pro- and anti- apoptotic genes, respectively. Furthermore, TF had a significant inhibitory effect on the migration and invasion of A549 cells (P<0.01). The mRNA expression levels of COX-2, Wnt and β-catenin were significantly downregulated in TF-treated A549 cells compared with controls. Additionally, treatment with TF inhibited tumor growth in mice, with a tumor inhibition rate of 64.07% compared with the controls. TF exhibited significant tumor inhibitory effects in vivo by promoting the apoptosis of tumor cells. In conclusion, the results suggested that TF may regulate lung cancer growth via the COX-2-Wnt/β-catenin signaling pathway. TF may serve as a novel anti-cancer agent for the treatment of lung cancer.