Enhancing secondary metabolite accumulation in medicinal plants to improve immunomodulatory activity

Despite progress in enhancing secondary metabolite accumulation to support plant growth and stress tolerance, relatively few studies have established direct links between these increases and enhanced immunoregulatory outcomes in humans. Bridging this gap is essential for advancing pharmacological applications and the development of effective plant-based immune therapeutics. Unlike previous reviews that primarily focus on metabolite enhancement strategies in isolation, this review proposes an integrative translational framework linking plant metabolic reprogramming, metabolite bioavailability, and downstream human immunomodulatory relevance. This review evaluates genetic, biochemical, and ecological strategies used to enhance secondary metabolite accumulation in medicinal plants and assesses their potential to translate into immunomodulatory effects. The available evidence indicates that while elicitor- and biostimulant-based approaches consistently enhance metabolite accumulation, their translation into clinically relevant outcomes is constrained by factors such as bioavailability, metabolic stability, and dose-dependent effects. The review further highlights key limitations and knowledge gaps, emphasising the need for integrative and translational research frameworks to link plant metabolic enhancement with human immune outcomes.