From Phytochemicals to Physiology: The Metabolic and Redox Effects of Botanical Extracts on Crops

Botanical extracts have emerged as promising biostimulants in agricultural systems because of their ability to modulate key metabolic and redox processes in crops, thereby increasing stress tolerance and productivity. This review synthesizes current knowledge on how botanical extracts influence plant metabolism and redox homeostasis, with a particular emphasis on their role in adaptive cellular responses. Evidence indicates that these extracts can increase antioxidant enzyme activity, regulate reactive oxygen species (ROS) signaling, and promote the accumulation of bioactive metabolites associated with improved stress tolerance and enhanced growth. This review also examines how agronomic practices, including nutritional management, water availability, light regimes, and preharvest biostimulant applications, together with emerging biotechnological approaches, can be strategically employed to optimize the bioactive composition and efficacy of botanical extracts. By integrating recent advances in metabolomics and transcriptomics, the manuscript highlights the biochemical and molecular reprogramming triggered by botanical extracts. It identifies key challenges, including variability in extract composition, lack of standardization, and context-dependent responses. Finally, future research directions are outlined, emphasizing the need for mechanistic understanding, quantitative evaluation of plant responses, and the development of standardized frameworks to support the sustainable application of botanical extracts in agriculture.