Synergy, Additive Effects, and Antagonism of Drugs with Plant Bioactive Compounds

To identify relevant studies, we performed a systematic literature search based on various scientific databases from 11 August 2024 to 30 December 2024. The search will be based on relevant keywords such as synergy, antagonism, plant bioactive compounds, and drug interactions supplemented with secondary terms such as phytochemicals, herb-drug interactions, pharmacokinetics, and pharmacodynamics.

Plant bioactives, including polyphenols, flavonoids, alkaloids, and terpenoids, display valuable biological activities that can interact with medications in three principal ways: synergy, additive effects, and antagonism. Synergy occurs when the combined effects of plant chemicals and pharmaceuticals outweigh the sum of their separate effects, increasing therapeutic effectiveness or allowing dosage decrease to reduce adverse effects. Additive effects occur when the combined impact equals the total individual effects, resulting in better outcomes without increasing risk. Antagonism occurs when a plant ingredient reduces or counteracts the effects of a medicine, thereby jeopardizing treatment. In addition, specific interactions may have no discernible effect. The chemical makeup of bioactive chemicals, medication pharmacokinetics, and individual patient characteristics such as genetics and metabolism all impact the intricacy of these interactions.