Anti-inflammatory Activity of Mollugo cerviana Methanolic Extract in LPS-induced Acute Inflammatory RAW 264.7 Macrophages

Comb Chem High Throughput Screen. 2021 Mar 1. doi: 10.2174/1386207324666210302101204. Online ahead of print.

Abstract

Background: The management of acute inflammation, which arises from complex biological responses to harmful stimuli, is an important determinant in recovery of the system from an otherwise detrimental outcome such as septicemia. However, the side effects and limitations of current therapeutics necessitate the development of newer and safer alternatives. Mollugo cerviana is a common medicinal herb of the Indian subcontinent and has been traditionally used for its fever mitigating, anti-microbial and hepatoprotective action. We have already reported the rich presence of radical scavenging phytochemicals in the plant extracts and their strong antioxidant properties.

Objective: In the present study, we have evaluated the anti-inflammatory effects of methanolic extract (ME) of the areal parts of M. cerviana in a lipopolysaccharide (LPS)-induced acute inflammatory cell culture model.

Method: RAW 264.7 mouse macrophages cell were stimulated by the bacterial endotoxin LPS at a concentration of 1 µg/mL. Cytotoxicity and anti-inflammatory potential of ME were carried out.

Results: M. cerviana extract concentration up to 150 µg/ml was found to be non-toxic to cells (MTT and NRU assay). LPS induces acute inflammation by binding to TLR-4 receptors, initiating downstream signalling cascade that result in pro-inflammatory cytokine secretion. Extract treatment at 100 µg/ml suppressed LPS-induced gene expression (qPCR) and secretion (ELISA) of pro-inflammatory cytokines IL-1β, IL-6 and TNF-α, and the chemokine CCL2, indicating a dampening of the acute inflammatory cascade. LPS-induced elevation of ROS level (DCFDA method) was significant reduced by extract treatment. Nitric oxide production, as indicated by nitrite level, was significantly reduced post extract treatment.

Conclusion: From this study, it is demonstrated that M. cerviana methanolic extract has potent anti-inflammatory effect in the in vitro acute inflammation model of LPS-stimulated RAW 264.7 cells. There is not reported study so far on the anti-inflammatory properties of M. cerviana in an LPS-induced acute inflammatory model which closely mimics a human bacteremia response. Hence, this study highlights the therapeutic potential of this extract as a source of anti-inflammatory lead molecules.

Keywords: Acute Inflammation; Anti-inflammatory; Lipopolysaccharide; Macrophage; Pro-inflammatory Cytokines.; ROS.