Evaluation of the antiviral and anti-inflammatory activity of Acalypha indica L. in LPS-induced macrophages via modulating NF-κB pathway

Abstract

Background

Inflammation plays a major role in SARS-CoV-2 infection severity, as an excessive immune response can cause tissue damage and severe respiratory distress. Phytochemicals, with their anti-inflammatory and immune-regulating properties, offer the potential in helping to manage these effects. Acalypha indica, an annual herb from the Euphorbiaceae family, is traditionally used to treat respiratory issues.

Purpose

The study aims to assess the phytochemical profile and dual anti-inflammatory and anti-SARS-CoV-2 activity of A. indica. The current study offers a targeted approach to prevent SARS-CoV-2 infection and associated inflammatory conditions using a chemically characterized purified fraction.

Methods

UPLC-QTOF-MS and GC–MS were used for phytochemical profiling. The in vitro anti-inflammatory activity and anti-SARS-CoV-2 activity were assessed using ELISA cytokine estimation and pseudovirus entry inhibition assay, respectively. Additionally, acute toxicity was evaluated following OECD guidelines 425, which ensures the safety of the extract for its therapeutic use.

Results

The major compounds identified are gallic acid, kaempferol, rutin, acalyphin, phytol, stigmasterol, β-sitosterol from the group of phenolics, flavonoids, cyanogenic glycosides, acyclic diterpene alcohol, and sterols, respectively. The crude extract and fractions of A. indica reduced the production of lipopolysaccharide (LPS) induced TNF-α and IL-6. Notably, the hexane-soluble fraction demonstrated the strongest activity, an 8–9-fold reduction compared to LPS only. The pseudovirus expressing SARS-CoV-2 Spike assay displayed that the hexane-soluble fraction restricted the entry of pseudovirus particles expressing SARS-CoV-2 Spike glycoprotein, with an IC₅₀ value of 739 μg/mL.

Conclusion

Acalypha indica extract shows anti-inflammatory and anti-SARS-CoV-2 properties, suggesting its potential for treating inflammation-related viral infections.