Foeniculum vulgare Mill. inhibits lipopolysaccharide-induced microglia activation and ameliorates neuroinflammation-mediated behavioral deficits in mice

Abstract

Objective: To investigate the effect of Foeniculum vulgare extract against lipopolysaccharide (LPS)-induced microglial activation in vitro as well as cognitive behavioral deficits in mice. Methods: LPS-activated BV-2 cell viability was measured using MTT assay and reactive oxygen species (ROS) was studied using DCF-DA assay. The antioxidative enzymes and pro-inflammatory mediators were analyzed using respective ELISA kits and Western blotting. For in vivo testing, LPS (1 mg/kg, i.p.) was given daily for five days in male Swiss albino mice to produce chronic neuroinflammation. Cognitive and behavioral tests were performed using open-field, passive avoidance, and rotarod experiments in LPS-induced mice. Results: Foeniculum vulgare extract (25, 50 and 100 µg/mL) significantly attenuated the LPS-activated increase in nitric oxide (NO), ROS, cyclooxygenase-2, inducible NO synthase, IL-6, and TNF-alpha (P < 0.05). Moreover, LPS-induced oxidative stress and reduced antioxidative enzyme levels were significantly improved by Foeniculum vulgare extract (P < 0.05). The extract also regulated the NF-κB/MAPK signaling in BV-2 cells. In an in vivo study, Foeniculum vulgare extract (50, 100, and 200 mg/kg) markedly mitigated the LPS-induced cognitive and locomotor impairments in mice. The fingerprinting analysis showed distinctive peaks with rutin, kaempferol-3-O-glucoside, and anethole as identifiable compounds. Conclusions: Foeniculum vulgare extract can ameliorate LPS-stimulated neuroinflammatory responses in BV-2 microglial cells and improve cognitive and locomotor performance in LPS-administered mice.

Keywords

Foeniculum vulgare / Microglia / Lipopolysaccharide / Antioxidant / Neuroinflammation / MAPK signaling / Cognition

Acknowledgments

This work was supported by Konkuk University in the year 2022.

Conflict of interest statement

The authors declare that they have no conflict of interest.

Funding

The authors received no extramural funding for the study.

Data availability statement

The data supporting the findings of this study are available from the corresponding authors upon request.

Authors’ contributions

SK designed the work and was involved in data collection. Both SRK and RA were involved in data analysis and interpretation. SK and SRK were involved in drafting the article and critical revision of the article. SK, RA and SRK finally approved the version to be published.

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