Swertia purpurascens Wall: Evaluation of its antifibrotic activity in an in vitro model of oral submucous fibrosis.

Abstract

Background: Oral submucous fibrosis (OSF) is a chronic, progressive, and potentially malignant condition prevalent in Southeast Asia, primarily associated with betel nut consumption. The pathogenesis involves overexpression of transforming growth factor beta 1 (TGF-β1), which drives fibroblast activation and excessive extracellular matrix (ECM) deposition. Despite available therapies, effective long-term management remains elusive.

Objective: This study investigates the antifibrotic activity of Swertia purpurascens Wall extract, a xanthone-rich medicinal herb, by evaluating its effect on TGF-β1 expression, fibroblast viability, and ECM remodelling in primary OSF-derived human fibroblasts.

Methods: Primary fibroblasts were isolated from OSF biopsy tissues, authenticated through STR profiling, and phenotypically confirmed by vimentin expression using flow cytometry. Cells were treated with Swertia purpurascens extract at concentrations ranging from 31.25 to 500 μg/mL. TGF-β1 secretion was quantified using ELISA. Cell viability was measured via MTT assay over a 72-hour period. Collagen gel contraction assays assessed ECM remodelling capacity.

Results: A significant, dose-dependent reduction in TGF-β1 secretion was observed, with the highest concentration (500 μg/mL) achieving nearly 50% inhibition (P < 0.05). Fibroblast viability decreased linearly over time (R ² = 0.998), indicating sustained cytostatic activity. Post-treatment gel contraction also reduced by approximately 50%, supported by linear regression analysis (R ² = 0.955).

Conclusion: Swertia purpurascens Wall extract effectively attenuates fibrosis-related cellular processes in OSF-derived fibroblasts. Its ability to suppress TGF-β1 signalling, limit fibroblast proliferation, and inhibit ECM contraction highlights its potential as a plant-based antifibrotic therapy for OSF and related fibrotic disorders.