Gynura procumbens (Lour.) Merr. extract attenuates monocyte adherence to endothelial cells through suppression of the NF-?B signaling pathway

Ethnopharmacological relevance: Gynura procumbens (Lour.) Merr. (GP) is a herbaceous plant that grows in Malaysia and other parts of Southeast Asia. The herb is consumed as a remedy for various inflammatoryassociated diseases, such as cancer, rheumatism, hypertension, diabetes mellitus and hyperlipidemia. Scientific studies demonstrate that GP extract possesses cardioprotective and anti-inflammatory effects. Cardiovascular disease is mainly caused by atherosclerosis, and inflammation plays a major role in all phases of atherosclerosis. The early inflammatory events in atherogenesis are the activation of endothelial cells and the recruitment of monocytes. Aim of the study: This study aimed to evaluate the inhibitory effect of 80% ethanol extract of GP leaves (GPE) on the adherence of monocytes to the activated human endothelial cells and its underlying mechanism. Material and methods: Qualitative and quantitative analyses of the extract were carried out by using a validated HPLC and UHPLC-MS/MS methods. The MTT test was used to select the range of concentration of extract for this study. The effect of GPE on TNF-alpha-induced monocyte-endothelial interaction was determined by the in vitro adhesion assay. Expression of cell surface proteins (ICAM-1, VCAM-1) and phosphorylation of nuclear factor kappa B (NF-kappa B) were determined by western blot, while expression of a chemokine (MCP-1) was identified by an enzyme-linked immunosorbent assay. Results: HPLC and UHPLC-MS/MS analyses indicated that GPE contained chlorogenic acid, nicotiflorin and astragalin as the major compounds. GPE at 20, 40 and 60 mu g/mL concentrations showed a significant reduction in monocyte adherence to endothelial cells and expression of ICAM-1 and MCP-1. However, only GPE at concentrations of 40 and 60 mu g/mL was able to reduce VCAM-1 expression. Furthermore, GPE significantly inhibited IKK alpha/beta, I kappa B alpha, NF-kappa B phosphorylation and NF-kappa B translocation. Conclusion: In conclusion, GPE may inhibit monocyte adherence to the activated endothelial cells and expression of ICAM-1, VCAM-1 and MCP-1, which are important proteins for monocyte-endothelial interaction, by suppressing the NF-kappa B signaling pathway. The results of this study support the traditional use of GPE to counteract inflammation-associated diseases and suggest that GP can be a potential source for bioactive compounds for the development of anti-inflammatory agents to prevent atherosclerosis.

Automated summary

This study aimed to evaluate the inhibitory effect of 80% ethanol extract of Gynura procumbens leaves (GPE) on the adherence of monocytes to activated human endothelial cells and its underlying mechanism.