Immunomodulatory Medicinal Plants

The immune system maintains homeostasis through a highly coordinated network of cellular and molecular interactions regulated by cytokines and their receptors. Disruption of this balance can result in immune-related disorders, prompting the need for effective immunomodulatory therapies. Although synthetic and biological immunodrugs have shown clinical efficacy, their high cost and adverse effects have driven increasing interest toward traditional medicinal systems such as Ayurveda and Siddha, which utilize plant-based formulations for immune enhancement and regulation. Numerous medicinal plants possess potent immunomodulatory activities, influencing both innate and adaptive immune responses through mechanisms that enhance phagocytosis, antibody production, and cytokine expression. In this review, immunomodulatory potential of several medicinal plants—including Withania somnifera, Morus alba, Sophora subprostrata, Acacia catechu, Jatropha curcas, Achillea wilhelmsii, Picrorhiza scrophulariiflora, Plantago asiatica, Panax ginseng, Caesalpinia bonducella, Allium sativum, and Cynodon dactylon—is summarized based on in vitro and in vivo experimental studies. These plants demonstrate diverse mechanisms of immune stimulation and suppression, supporting their traditional use and highlighting their potential as sources for novel immunotherapeutic agents. Continued pharmacological investigation, standardization, and clinical validation of these herbal immunomodulators may lead to the development of safe, affordable, and effective alternatives for immune-related disorders.