ABSTRACT
OBJECTIVE: Hibiscus protocatechuic acid (PCA) is a food-derived polyphenol antioxidants used as a food additive and a traditional herbal medicine. In this study, PCA was to determine its effect on cell proliferation and cell cycle progression in primary cultured human uterine leiomyoma cells. METHODS: The effect of PCA on cell proliferation and cell cycle progression was examined in the primary cultured human uterine leiomyoma cells. MTT reduction assay was carried out to determine the viability of uterine leiomyoma cells. Cell cycle analysis for Hibiscus protocatechuic acid treated leiomyoma cells was done by FACS analysis. DNA fragmentation assay was performed to determine fragmentation rate by PCA in leiomyoma cells. Western blot analysis was done using anti pRB, anti-p21(cip1/waf1), anti-p53, anti-p27(kip1), anti-cyclinE, anti CDK2 antibodies to detect the presence and expression of these proteins in PCA treated myoma cells. RESULTS: PCA induced growth inhibition in a dose dependent manner, treatment with 5 mmol/L PCA blocked 80% cell growth. FACS results showed that there was increased the percentage of cells in sub G1. DNA fragmentation assay by ELISA was done to find the rate of apoptosis. Apoptosis took place but in a dose dependent manner. From Western blot analysis it revealed PCA induced the expression of p21(cip1/waf1) and p27(kip1) increasingly and was not mediated by p53. Caspase-7 pathway was activated and dephosphorylation of pRB took place. CONCLUSION: In Conclusions, PCA, a polyphenol antioxidant, inhibited cell proliferation and induced cell cycle arrest at sub G1 phase by enhancing the production of p21cip1/waf1 and p27kip1. These results indicate that PCA will be a promising agent for use in chemopreventive or therapeutics against human uterine leiomyoma.