The effect of roselle (Hibiscus sabdariffa l.) flowers extract on the apoptosis of fibroblast proliferation in keloids

BACKGROUND: Keloid is a benign fibroproliferative dermal disorder as a result of dysregulation wound healing process in susceptible individuals. The pathogenesis is not clearly known yet, but upregulation of transforming growth factor-β1 (TGF-β1) was found to have a significant role in inducing hyperproliferation of fibroblast cells. Roselle (Hibiscus sabdariffa L.) flower extract has been found to have high content of polyphenols. Some studies have shown inhibition effect of H. sabdariffa polyphenols extract on TGF-β1, and as result affects fibroblast proliferation. Therefore, roselle flower extract might have a significant role in the prevention of keloid formation. AIM: The objective of the study was to determine the effect of roselle flower extract on fibroblast cells proliferation in human keloid. METHODS: An experimental controlled trial of 10 different concentrations (1.96 μg/ml, 3.91 μg/ml, 7.81 μg/ml, 15.63 μg/ml, 31.25 μg/ml, 62.50 μg/ml, 125 μg/ml, 250 μg/ml, 500 μg/ml, and 1000 μg/ml) of roselle (H. sabdariffa L.) flower extract was done on cultured fibroblast cells originated from human keloid biopsied tissue. Tunnel assay was done to evaluate the apoptosis rate of the cultured fibroblast cells on each concentration. Determination of TGF-β1 titer of the cultured human keloid fibroblast cells in and cytotoxicity assay of the extract on cultured normal human fibroblast cells in each concentration were done with enzyme-linked immunosorbent assay method. All the assays were done in triple repetition. Statistical analysis using linear regression test was done to determine the association between the concentration of roselle flower extract with apoptosis rate and TGF-β1 titer. One-way ANOVA was used to analyze the results of cytotoxicity assay. RESULTS: Apoptosis rate of the cultured fibroblast cells was found to be increased dose dependently with roselle flower extract concentration (r² = 0.797; p < 0.05). TGF-β1 titer was inversely related with the extract concentration (r² = 0.501; p < 0.05). Cytotoxicity assay revealed that no differences in absorbance value and viability cells were found in each concentration. CONCLUSION: Roselle (H. sabdariffa L.) flower extract was found to induce apoptosis of the cultured fibroblast cells and reduction of TGF-β1 titer in dose-dependent pattern, without cytotoxicity effect against human fibroblast cells.