In vitro assessment of cell proliferation and migration induced by crude lychee seed extract in human gingival fibroblast cells (HGF-1)

Abstract Background: Human gingival fibroblasts (HGFs) are central regulators of oral wound healing. Oxidative stress impairs fibroblast viability and motility, potentially delaying wound healing. Lychee seeds are rich in antioxidants, such as phenolics and flavonoids. Their antioxidant effect is expected to improve oral wound healing. Therefore, this study evaluated the effect on wound healing, using the cytotoxicity, proliferation, and migration assay of crude lychee seed extract (LSE) on the HGF-1 cell line. Methods: Crude LSE was prepared by 95% ethanolic extraction, and its phenolic and flavonoid composition was characterized by ultra-high performance liquid chromatography-mass spectrometry. HGF-1 cells were treated with 0.1–100 µg/mL crude LSE. Cytotoxicity was assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in accordance with ISO 10993-5, and morphology was examined by phase-contrast microscopy. Cell proliferation was monitored using the MTT assay over 7 days, and cell migration was evaluated by an in vitro scratch-wound healing assay at 8, 16, and 24 h. Data were analyzed using one-way analysis of variance (ANOVA) with Tukey's honestly significant difference (HSD), and statistical significance was set at p < 0.05. Results: Phytochemical profile of the crude LSE showed 45 compounds across 6 chemical classes, including 15 phenolic and flavonoid species. Crude LSE was non-cytotoxic at 0.1–50 µg/mL (viability > 70%), while 100 µg/mL was marginally below the threshold without reaching statistical significance compared with the control group. Low concentrations (1–20 µg/mL) significantly enhanced HGF-1 proliferation on Day 5, and 0.1 µg/mL produced the highest proliferation on Day 7 (p < 0.001 vs control), whereas 50 and 100 µg/mL suppressed growth. In the scratch assay, 0.1–20 µg/mL accelerated gap closure at 8 h, with 5 and 10 µg/mL showing the greatest migration at 24 h, while 50 and 100 µg/mL delayed closure. Conclusions: Crude LSE is non-cytotoxic to HGFs at concentrations up to 50 µg/mL and exerts concentration-dependent stimulatory effects on fibroblast proliferation and migration, with 0.1–10 µg/mL emerging as the most promising range. Together with its rich phenolic and flavonoid profile, these findings support further investigation of crude LSE and its purified constituents as candidate agents for promoting oral soft tissue healing.