Primula vulgaris belongs to the genus Primula, members of which are frequently used in folk medicine. Various studies have investigated the cytotoxic effect of different Primula species, but there have been limited studies on the cytotoxic effect of P. vulgaris. The aim of this study was to investigate the cytotoxic effects, and possible mechanisms involved, of P. vulgaris flower extract on human cervical cancer (HeLa) cells. The cytotoxic effect of the extract on HeLa cells was revealed using the MTT assay. Mechanisms involved in the extract's cytotoxic effect were then investigated in terms of apoptosis, mitochondrial membrane potential, and the cell cycle, using fluorometric methods. P. vulgaris flower extract exhibited selective cytotoxic effects against HeLa cells by arresting their cell cycle at the S phase, and inducing the number of apoptotic cells compared to normal fibroblast cells by reducing mitochondrial membrane potential in a concentration-dependent manner. This is the first study to reveal the antiproliferative effect of P. vulgaris flower extract. Further studies are now needed to identify the cytotoxic molecules in the extract and their mechanisms.

Rosa canina is a member of the genus Rosa that has long been used for medical objectives. Several studies have reported cytotoxic effects of different Rosa species, but there has been only limited investigation of the cytotoxic effect of R. canina. The purpose of the current study was to examine the potential effect of R. canina extract on cell viability, the cell cycle, apoptosis, and the expression of telomerase in human colon cancer (WiDr) cells. The cytotoxic effect of the extract was determined using MTT assay. The mechanism involved in the cytotoxic effect of the extract was then evaluated in terms of apoptosis and the cell cycle using flow cytometry. Mitochondrial membrane potential (MMP) was investigated using the fluorometric method, and expression levels of telomerase were studied using RT-PCR. R. canina extract exhibited a selective cytotoxic effect on WiDr cells compared with normal colon cells. The extract induced cell cycle arrest at the S phase and apoptosis via reduced MMP in WiDr cells. R. canina extract significantly repressed telomerase expressions at treatment times of 48 and 72 h in WiDr cells. Our results suggest that R. canina may have considerable potential for development as a novel natural product-based anticancer agent.