Protective Effects of Medicinal Plant Decoctions on Macrophages in the Context of Atherosclerosis

Abstract

Atherosclerosis is a hallmark of most cardiovascular diseases. The implication of macrophages in this pathology is widely documented, notably for their contribution to lipid accumulation within the arterial wall, associated with oxidative stress and inflammation processes. In order to prevent or limit the atherosclerosis damage, nutritional approaches and medicinal plant-based therapies need to be considered. In Reunion Island, medicinal plant-based beverages are traditionally used for their antioxidant, lipid-lowering and anti-inflammatory properties. The aim of our study was to assess the protective effects of eight medicinal plant decoctions in an in vitro model of RAW 264.7 murine macrophages exposed to pro-atherogenic conditions (oxidized low-density lipoproteins—ox-LDL—E. coli Lipopolysaccharides—LPS). The impact of polyphenol-rich medicinal plant decoctions on cell viability was evaluated by Neutral Red assay. Fluorescent ox-LDL uptake was assessed by flow cytometry and confocal microscopy. Activation of NF-κB was evaluated by quantification of secreted alkaline phosphatase in RAW-Blue™ macrophages. Our results show that medicinal plant decoctions limited the cytotoxicity induced by ox-LDL on macrophages. Flow cytometry analysis in macrophages demonstrated that medicinal plant decoctions from S. cumini and P. mauritianum decreased ox-LDL uptake and accumulation by more than 70%. In addition, medicinal plant decoctions also inhibited NF-κB pathway activation in the presence of pro-inflammatory concentrations of E. coli LPS. Our data suggest that medicinal plant decoctions exert protective effects on ox-LDL-induced cytotoxicity and limited macrophage lipid uptake. Moreover, herbal preparations displayed anti-inflammatory properties on macrophages that can be of interest for limiting the atherosclerotic process.

Quality assessment and Q-markers discovery of Tongsaimai tablet by integrating serum pharmacochemistry and network pharmacology for anti-atherosclerosis benefit

“…The deposition of subendothelial lipoproteins leads to the aggregation of monocytes, that later differentiate into macrophages in the intimal compartment [21]. Macrophages uptakes oxidation-modified lipoproteins such as oxidized low-density lipoproteins (ox-LDLs) excessively and disorderly which mediated by scavenger receptors to form cholesterol-overloaded foam cells [22]. Furthermore, these foam cells trigger a series of inflammatory reactions, contributing to the necrotic core formation of atheromatous plaques.…”

Aqueous Extract of Psiloxylon mauritianum, Rich in Gallic Acid, Prevents Obesity and Associated Deleterious Effects in Zebrafish

“…P. mauritianum is a plant widely used in the Mascarene Islands (Mauritius and Reunion Islands) for its traditional benefits, considering its anti-cholesterol and “anti-diabetic” effects [ 32 , 33 ]. Recent scientific experiments on this medicinal plant have demonstrated its anti-bacterial, antiviral, anti-inflammatory and antioxidant properties [ 25 , 26 , 63 , 64 ]. In this study, we investigated for the first time the in vivo toxicity of an aqueous extract of P. mauritianum according to the OECD guidelines, using a zebrafish model.…”

“…These findings support the traditional lipid-lowering effect of P. mauritianum . Indeed, this medicinal plant is supposed to increase cholesterol elimination from the body, and recent work also showed a decrease in oxidized LDL uptake by macrophages under P. mauritianum treatment [ 21 , 26 , 32 ]. Of interest, P. mauritianum exerts striking effects on overfed adult zebrafish (DIO protocol) by preventing weight gain, increased BMI, hyperglycemia and liver steatosis, and consequently improving almost all deleterious effects induced by overfeeding.…”

“…Some of them are traditionally described and used for their suggested “anti-diabetic” and/or lipid-lowering properties [ 21 , 22 , 23 , 24 , 25 ]. Unfortunately, scientific data are lacking to confirm such properties, although recent data from our group document some of these beneficial effects [ 25 , 26 , 27 , 28 , 29 , 30 , 31 ]. Recently, 27 Reunionese plants have been registered in the French pharmacopeia [ 21 , 22 ].…”

Pharmacological Properties of Polyphenols: Bioavailability, Mechanisms of Action, and Biological Effects in In Vitro Studies, Animal Models, and Humans

“…Moreover, medicinal plant extracts have long been used, especially in oriental cultures. Decoctions of 1 g/L teabag containing S. cumini and P. mauritianum have been shown to decrease ox-LDL uptake by more than 70%, while inhibiting the NF-κB pathway in the presence of pro-inflammatory concentrations of E. coli lipopolysaccharides in RAW 264.7 murine macrophages [26]. Furthermore, salvianolic acid A, a natural polyphenol extract widely used as traditional medicine in China for its cardioprotective functions, was recently shown to protect against lipotoxicity-induced myocardial damage at 5, 10, 20, and 40 µM through a TLR4/MAPKs signaling pathways in H9c2 cells [27].…”