RESUMO
Objective: Phenolic acids are well-known phytochemicals that are detected in a wide variety of medicinal plants, and their antiproliferative effects on cancer cells are known, but their mechanisms are poorly revealed. In most of cancer cells, telomerase reverse transcriptase (hTERT) is a dominant factor of telomere length regulation. The hTERT expression promotes invasiveness in tumor cells and is a hallmark of cancer. Therefore, in this study, the probable inhibitory effects of caffeic (Caf), coumaric (Cum), and ferulic acids (Fer) are investigated on the hTERT expression pattern in HepG2 cells. Methods: The MTT, apoptosis assays, and real-time PCR analysis were applied to evaluate viability, cytotoxicity, and hTERT gene expression level, respectively. Results: All of the studied phenolic acids showed cytotoxic effects on HepG2 cells in a timely manner and presented a time-dependent inhibitory effect on the growth of HepG2 cells. They reduced percentage of viable cells and induced apoptosis. Also, these phenolic acids had significant inhibitory effects on hTERT gene expression. Conclusion: These findings suggest that cell viability along with hTERT gene expression in HepG2 cells could be reduced by Cum, Caf, and Fer. As different cancer cells are resistant to conventional chemotherapeutics, this type of results proposes the telomerase as a proper target of cancer therapy development by natural products.
RESUMO
Background: Rosa canina has been traditionally known as a medicinal plant. Different applications of fruits (Rose hip) comprise the food, perfume, and cosmetic industries. Objectives: This study aimed to prepare an enriched polyphenolic fraction from Rosa canina in addition to its biological activities. Methods: Poly phenolic enriched fraction was prepared using Amberlite XAD-7 for removing unwanted components. Phenols, flavonoids, and anthocyanins content analyses showed that they increased significantly compared to the extract. HPLC analysis showed that this fraction is a rich source of ascorbic acid. Results: The results of the DPPH, ferric-reducing antioxidant power (FRAP), ABTS, and nitric oxide assay confirmed that the antioxidant activities of the fraction had been increased compared to the extract. The oxygen radical absorbance capacity (ORAC) assay and cellular antioxidant activity of the fraction also confirmed its potential antioxidant activity. This fraction showed xanthine oxidase inhibitory activity at 100 µg/mL concentration. Comet assay analysis revealed that this fraction at 25 - 100 µg/mL concentrations inhibited H2O2 genotoxicity in human lymphocytes. Conclutions: This study suggests that the fruit of Rosa canina could be considered as a potential antioxidant, a xanthine oxidase inhibitor, and an antigenotoxic source, and the application of Amberlite XAD-7 improves extraction efficiencies through enrichment of phenolic compounds in this plant.