In vitro evaluation of the wound healing potential of Bajong LN rice extracts: on cellular activities and protein expression in human gingival fibroblasts, HGF cells

Oral wound healing is a complex and dynamic process that remains underexplored despite its clinical importance. Fibroblasts, particularly human gingival fibroblast (HGF) cells play a central role in this process through their involvement in cell proliferation, migration, extracellular matrix (ECM) remodelling and growth factor signalling. While rice (Oryza sativa L.) extracts have demonstrated regenerative potential in dermal and gastrointestinal tissues, their therapeutic relevance and mechanistic roles in oral fibroblast-mediated healing are poorly understood. Notably, Malaysia’s indigenous Bajong Lubok Nibong (Bajong LN) rice, traditionally used for treating skin and oral lesions has yet to be scientifically validated in an oral-specific wound healing model. To address this knowledge gap, this study aimed to investigate the cellular and molecular effects of Bajong LN rice methanolic (BLN-ME) and aqueous (BLN-A) extracts on HGF cells, focusing on their potential to promote oral wound healing through modulation of cell viability, proliferation, migration and key signalling pathways. This study employed a structured three-phase in vitro approach. In Phase 1, five crude extracts (hexane, ethyl acetate, ethanol, methanol and aqueous) were prepared via successive maceration and screened for cytocompatibility using an optimised MTS assay. BLN-ME and BLN-A were selected for their significant viability-promoting effects on HGF cells without cytotoxicity. Phase 2 evaluated the cellular effects of optimal concentrations 250 μg/ml for BLN-ME and 500 μg/ml for BLN-A on HGF cells; and obtained IC50 as well as IC80 on ORL-48 oral squamous carcinoma cells. The functional cellular assays included short- and long-term proliferation (MTS, TBE, clonogenic assays), wound closure (scratch assay) and cell migration (Transwell migration assay). Both extracts enhanced HGF regeneration without inducing malignant cell growth, suggesting therapeutic selectivity for oral wound healing. In Phase 3, ELISA-based molecular profiling revealed upregulation of key autocrine/paracrine growth factors (IGF-1, PDGF-BB, bFGF and EGF) which facilitated receptor tyrosine kinase (RTK) signalling and activation of the downstream PI3K/AKT/mTOR pathway, as confirmed via LY294002 and rapamycin inhibition (p < 0.05). Parallel increases were observed in wound-associated effector proteins (FAK, MMP-9, COL-1, MMP-1, TIMP-1 and fibronectin) with a regulated MMP-1/TIMP-1 ratio maintained below 1.0, indicating balanced ECM turnover. Collectively, the findings demonstrated that both BLN-ME and BLN-A act as selective, multi-targeted modulators of regenerative activity in HGF cells, with BLN-ME showing slightly higher potency across assays. Notably, these extracts did not stimulate ORL-48 oral cancer cell growth, thereby affirming their cyto-selective safety profile. These results provide mechanistic clarity and position Bajong LN rice extracts as promising candidates for oral wound healing, with translational potential for future in vivo and clinical applications.