Cytotoxic effect of hydro-alcoholic extract of pomegranate (Punica granatum L.) flowers and isolated ursolic acid on B16f10 melanoma cells

Background: Melanoma is the most serious form of skin cancer and it has the highest rate of growth among different types of cancers. Ursolic acid (UA), a natural pentacyclic triterpenoid, is a major bioactive compound in several traditional medicinal plants including pomegranate (Punica granatum L.) flower. UA has very important biological and pharmacological functions. Objective: In this study, cytotoxic effects of ethanol extract of pomegranate flowers and isolated UA against B16f10 mouse melanoma cells were investigated. Methods: The isolation of UA from pomegranate flowers was done by using ultrasound-assisted extraction followed by normal-phase flash chromatography. The chemical structure of isolated UA was identified by GC-MS, IR and 1H-NMR spectra. The ethanol extract of pomegranate flowers and isolated UA were then tested for the cytotoxicity against B16f10 mouse melanoma cell lines. Cell viability was determined using MTT assay. Results: Ursolic acid was successfully isolated from pomegranate flowers by using normal-phase flash chromatography. After one flash chromatography run, the purity of UA reached more than 97% with a total yield of 0.1 % of dried pomegranate flower powder. Treatment of B16f10 cells with ethanol extract of pomegranate flowers and isolated UA exhibited significant anti-proliferative activity after incubation for 48 and 72 hours. It was observed for pomegranate flower extract in a concentration and time dependent manner. Conclusion: The results suggested that pomegranate flower extract and isolated UA can be encouraging compounds in the prevention and treatment of melanoma.