Almond and walnut hulls are agro-industrial by-products, which contain a wide variety of polyphenol compounds including phenolic acids and flavonoids that possess antioxidant and anti-bacterial properties. To valorize the medicinal value of almond and walnut hulls, the effect of their phenolic extract on proliferation, migration, and apoptosis of bone tumor cells was investigated. Our findings revealed that phenolic-rich extract from almond (AHE) and walnut (WHE) inhibited the proliferation of the bone tumor cells in a dose-dependent manner with less cytotoxic effect on the normal cells. Both AHE and WHE reduced mitochondrial membrane potential and the tumor cell migration and guided cells toward apoptotic death following caspase activation. To investigate the mechanism of action of AHE and WHE, we found that they reduced the intracellular ROS and disturbing the naturally occurring equilibrium between anti- and pro-oxidant in the tumor cells. The data obtained from this study demonstrated the anti-proliferative, apoptosis induction, and anti-migration properties of AHE and WHE, which is presumably related to their polyphenolic compounds. Therefore, the hull extract would be considered as an appropriate candidate for fight against cancer.

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