Myricetin induces apoptosis and enhances chemosensitivity in ovarian cancer cells

Fruits as Prospective Reserves of bioactive Compounds: A Review

Bioactive natural products have always played a significant role as novel therapeutical agents irrespective of their source of origin. They have a profound effect on human health by both direct and indirect means and also possess immense medicinal properties. Fruit species are largely appreciated and highly consumed throughout the world. Epidemiologic information supports the association between high intake of fruits and low risk of chronic diseases. There are several biological reasons why the consumption of fruits might reduce or prevent chronic diseases. Fruits are rich sources of nutrients and energy, have vitamins, minerals, fiber and numerous other classes of biologically active compounds. Moreover, parts of the fruit crops like fruit peels, leaves and barks also possess medicinal properties and have been included in this review. The most important activities discussed in this review include antidiabetic, anticancer, antihypertensive, neuroprotective, anti-inflammatory, antioxidant, antimicrobial, antiviral, stimulation of the immune system, cell detoxification, cholesterol synthesis, anticonvulsant and their ability to lower blood pressure. Several phytochemicals involved in this context are described with special emphasis on their structural properties and their relativity with human diseases.

Myricetin-induced apoptosis of triple-negative breast cancer cells is mediated by the iron-dependent generation of reactive oxygen species from hydrogen peroxide

Myricetin is a dietary phytochemical with anticancer activity; however, the effect of myricetin on breast cancer cells remains unclear. Here, we show that myricetin inhibited the growth of triple-negative breast cancer (TNBC) cells but was less inhibitory for normal cells. The effect of myricetin was comparable to epigallocatechin gallate and doxorubicin, and greater than resveratrol and cisplatin. Myricetin-treated TNBC cells showed evidence of early and late apoptosis/necrosis, which was associated with intracellular reactive oxygen species (ROS) accumulation, extracellular regulated kinase 1/2 and p38 mitogen-activated protein kinase activation, mitochondrial membrane destabilization and cytochrome c release, and double-strand DNA breaks. The antioxidant N-acetyl-cysteine protected myricetin-treated TNBC cells from cytotoxicity due to DNA damage. Myricetin also induced hydrogen peroxide (H₂O₂) production in cell-free culture medium, as well as in the presence of TNBC cells and normal cells. In addition, deferiprone-mediated inhibition of intracellular ROS generation via the iron-dependent Fenton reaction and inhibition of extracellular ROS accumulation with superoxide dismutase plus catalase prevented myricetin-induced cytotoxicity in TNBC cell cultures. We conclude that the cytotoxic effect of myricetin on TNBC cells was due to oxidative stress initiated by extracellular H₂O₂ formed by autoxidation of myricetin, leading to intracellular ROS production via the Fenton reaction.