Therapeutic potential of paeoniflorin in atherosclerosis: A cellular action and mechanism-based perspective

Epidemiological studies have shown that the incidence, prevalence and mortality of atherosclerotic cardiovascular disease (ASCVD) are increasing globally. Atherosclerosis is characterized as a chronic inflammatory disease which involves inflammation and immune dysfunction. P. lactiflora Pall. is a plant origin traditional medicine that has been widely used for the treatment of various diseases for more than a millennium in China, Japan and Korean. Paeoniflorin is a bioactive monomer extracted from P. lactiflora Pall. with anti-atherosclerosis effects. In this article, we comprehensively reviewed the potential therapeutic effects and molecular mechanism whereby paeoniflorin protects against atherosclerosis from the unique angle of inflammation and immune-related pathway dysfunction in vascular endothelial cells, smooth muscle cells, monocytes, macrophages, platelets and mast cells. Paeoniflorin, with multiple protective effects in atherosclerosis, has the potential to be used as a promising therapeutic agent for the treatment of atherosclerosis and its complications. We conclude with a detailed discussion of the challenges and future perspective of paeoniflorin in translational cardiovascular medicine.

Paeoniflorin attenuates lipopolysaccharide-induced permeability of endothelial cells: involvements of F-actin expression and phosphorylations of PI3K/Akt and PKC

This study aimed to investigate the effects of paeoniflorin, the main active ingredient of the medicinal plant Paeonia lactiflora Pall., on the permeability of endothelial cells induced by lipopolysaccharide (LPS) and the underlying mechanisms. Human umbilical vein endothelial cells (HUVECs) were stimulated by LPS. Extravasated FITC-dextran reflecting permeability was assessed by multimode microplate reader, and the migration of bis-carboxyethyl-carboxyfluorescein acetoxy-methyl-labeled human acute monocytic leukemia cell line and leukemia cell line cells through HUVECs were analyzed by fluorescence microscopy. The phosphorylations of phosphatidylinositol 3-kinase (PI3K)/Akt, protein kinase C (PKC), and cofilin in HUVECs were assessed by western blotting, and the F-actin level was detected by laser scanning confocal microscopy. After LPS stimulation, inflammatory endothelial cells exhibited significantly increased permeability. Paeoniflorin (10, 30, and 100 μM) inhibited dextran extravasation and leukocyte migration through HUVECs induced by LPS in a concentration-dependent manner. Moreover, paeoniflorin was able to suppress the phosphorylations of PI3K/Akt, PKC, and cofilin, as well as F-actin reorganization in HUVECs induced by LPS. These findings revealed that paeoniflorin partly blocked LPS-induced endothelium permeability, supporting a new explanation for its anti-inflammatory effects.

Protective effects of peoniflorin against hydrogen peroxide-induced oxidative stress in human umbilical vein endothelial cells

Peoniflorin (PF), extracted from the root of Paeonia lactiflora Pall., has been reported to have anti-inflammation and antioxidant effects in several animal models. Herein, we investigated the protective effects of PF against hydrogen peroxide (H(2)O(2))-induced oxidative damage in human umbilical vein endothelial cells (HUVECs). HUVECs were treated by H(2)O(2) (240 µmol/L) with or without PF. PF significantly increased the percent cell viability of HUVECs injured by H(2)O(2) using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. By flow cytometric analysis, PF markedly attenuated H(2)O(2)-induced apoptosis and intracellular reactive oxygen species production. In addition, PF also displayed a dose-dependent reduction of lactate dehydrogenase leakage, malondialdehyde formation, and caspase-3 proteolytic activities in H(2)O(2)-treated cells, which was accompanied with a restoration of the activities of endogenous antioxidants, including total superoxide dismutase and glutathione peroxidase. Finally, Western blot data revealed that H(2)O(2) upregulated phosphorylation of extracellular signal-regulated kinase 1/2 in HUVECs, which was almost completely reversed by PF. Taken together, our data provide the first evidence that PF has a protective ability against oxidative damage in HUVECs. PF may be a candidate medicine for the treatment of vascular diseases associated with oxidative stress.

Paeoniflorin protects against lipopolysaccharide-induced acute lung injury in mice by alleviating inflammatory cell infiltration and microvascular permeability

OBJECTIVE

The present study aims to explore the effects of paeoniflorin (PF), a monoterpene glycoside isolated from the roots of Paeonia lactiflora Pallas, on acute lung injury (ALI) and the possible mechanisms.

MATERIALS AND METHOD

ALI was induced in mice by an intratracheal instillation of lipopolysaccharide (LPS, 1 mg/kg), and PF was injected intraperitoneally 30 min prior to LPS administration. After 24 h, lung water content, histology, microvascular permeability and proinflammatory cytokines in the bronchoaveolar lavage fluid were evaluated.

RESULTS

It was shown that PF (50, 100 mg/kg) could alleviate LPS-induced ALI, evidenced by reduced pulmonary edema, improved histological changes, and attenuated inflammatory cell accumulation in the interstitium and alveolar space as well as microvascular permeability. It also markedly down-regulated the expressions of proinflammatory cytokines interleukin (IL)-1β and tumor necrosis factor (TNF)-α at both transcription and protein levels. Additionally, PF inhibited the phosphorylations of p38 MAP kinase (p38) and c-Jun NH2-terminal kinase (JNK) but not extracellular signal-regulated kinase (ERK), and prevented the activation of nuclear factor-kappa B (NF-κB) in the lung tissues.

CONCLUSION

The findings suggest that PF is able to alleviate ALI, and the underlying mechanisms are probably attributed to decreasing the production of proinflammatory cytokines through down-regulation of the activation of p38, JNK and NF-κB pathways in lung tissues.