An Investigation of the Antiproliferative Effect of Rhododendron luteum Extract on Cervical Cancer (HeLa) Cells via Nrf2 Signaling Pathway

The aim of the present study was to investigate the role of Rhododendron luteum extract (RLE) in the induction of Nrf2‑related oxidative stress and endoplasmic reticulum (ER) stress in human cervical cancer (HeLa) cells. The antiproliferative effect of RLE on HeLa and fibroblast cells was determined using the MTT assay. The effects of RLE on the cell cycle, apoptosis, and production of reactive oxygen species (ROS) in HeLa cells were evaluated using fluorescent probes. The mRNA expression levels of Nrf2 [and its targets glutamate-cysteine ligase catalytic subunit (GCLC), and glucose-6-phosphate dehydrogenase (G6PD)], and C/EBP homologous protein (CHOP, an ER stress marker were determined using reverse transcription‑quantitative polymerase chain reaction (RT-PCR). The results demonstrated that RLE exhibited a selective cytotoxic effect (2.9-fold) on HeLa cells compared to fibroblast cells. RLE arrested the cell cycle at the S phase, and induced apoptosis, ER stress, and ROS formation. In addition, RLE significantly suppressed the expression levels of Nrf2, GCLC and G6PD (0.65, 0.69, and 0.54-fold, respectively) and increased the expression of CHOP (4.48-fold) in HeLa cells at 72 h of treatment (p < 0.05). These results show that the antiproliferative effect of RLE occurs through the Nrf2 and ER stress pathways, and the results should now be supported by further in vivo studies.

The Impact of Herbal Infusion Consumption on Oxidative Stress and Cancer: The Good, the Bad, the Misunderstood

The release of reactive oxygen species (ROS) and oxidative stress is associated with the development of many ailments, including cardiovascular diseases, diabetes and cancer. The causal link between oxidative stress and cancer is well established and antioxidants are suggested as a protective mechanism against cancer development. Recently, an increase in the consumption of antioxidant supplements was observed globally. The main sources of these antioxidants include fruits, vegetables, and beverage. Herbal infusions are highly popular beverages consumed daily for different reasons. Studies showed the potent antioxidant effects of plants used in the preparation of some herbal infusions. Such herbal infusions represent an important source of antioxidants and can be used as a dietary protection against cancer. However, uncontrolled consumption of herbal infusions may cause toxicity and reduced antioxidant activity. In this review, eleven widely consumed herbal infusions were evaluated for their antioxidant capacities, anticancer potential and possible toxicity. These herbal infusions are highly popular and consumed as daily drinks in different countries. Studies discussed in this review will provide a solid ground for researchers to have better understanding of the use of herbal infusions to reduce oxidative stress and as protective supplements against cancer development.