Molecular insights into dietary hormetic phytochemicals in Olea europaea L. (Olive) and Nigella sativa L. (Black seed): Implications for human health

• Phytochemicals in olive and black seed exhibit biphasic hormetic responses. • Hormesis involves beneficial effects at low doses, harmful at high doses. • Understanding molecular mechanisms aids in treating metabolic and age-related diseases. • Precise dosing within hormetic zones enhances therapeutic benefits and reduces risks. • Study emphasizes bioactive compounds' potential for disease prevention and health. Hormesis is defined as the biphasic dose response relationship which determines the dual activity of a phytochemical. In other words, when the same drug exhibits both beneficial and harmful effects at different concentrations. Phytochemicals present with considerable amounts in medicinal plants, especially Olea europaea L. (olive) and Nigella sativa L. (black seed) have multifaceted mechanisms which also demonstrate hormetic responses, as stated in various studies. Though these activities are known for decades, clinical implications of these mechanisms are less studied. Hence, a thorough understanding of hormetic responses at cellular and molecular level is essential for further research in the treatment of metabolic, chronic inflammation, and age-related disorders. Therefore, the aim of the current comprehensive review was to emphasize the importance of molecular hormetic mechanisms of bioactive compounds from Olea europaea L. (olive) and Nigella sativa L. (black seed) and focuses on their therapeutic potential for enhancing human health from disease prevention. Precise understanding of optimal dosage within hormetic zones is essential for ameliorated therapeutic effects that benefit various diseases and reduced off-target effects, adverse effects, etc., and improve the quality of life.