In Vitro Evaluation of Nelumbo nucifera Extracts in LPS-induced Raw 264. 7 Cells: Implications for Bronchitis Treatment

Background: Bronchitis, a respiratory disorder marked by airway inflammation, requires effective anti-inflammatory therapies. Plant-based agents such as Nelumbo nucifera (white-flowered variety) are traditionally used in respiratory ailments but lack sufficient scientific validation. Objective: The present study aimed to evaluate the in vitro anti-bronchitis potential of the alcoholic extract of Nelumbo nucifera white flower petals (NN 02) using LPS-induced RAW 264.7 macrophage cells. Methods: The anti-inflammatory activity was assessed through nitric oxide (NO) inhibition using the Griess assay, while cytotoxicity was evaluated by MTT assay. RAW 264.7 cells were treated with different concentrations of the extract (25, 50, and 100 µg) and compared with the standard drug dexamethasone (5 µg). Results: LPS stimulation significantly increased NO production (3.062 µM in the control). The extract exhibited a dose-dependent inhibition of NO release, with 22.27%, 48.91%, and 67.09% inhibition at 25, 50, and 100 µg, respectively. Dexamethasone showed the strongest inhibition (89.18%). MTT assay revealed good cell viability, with >73% viability at the highest dose (100 µg) and an IC₅₀ >100 µg, confirming non-toxic behaviour. Conclusion: The alcoholic extract of Nelumbo nucifera white flower petals demonstrates significant in-vitro anti-bronchitis activity by attenuating NO production without cytotoxicity. This activity may be attributed to bioactive phytochemicals such as flavonoids, alkaloids, and phenolics. The findings support its traditional use in respiratory disorders and warrant further phytochemical characterization and in vivo validation.