Abstract
Azadirachta indica (A. indica) (neem), revered as the "village pharmacy" across civilizations, represents a pharmacological treasure trove spanning human therapeutics, aquaculture nutrition, and integrated pest management. This comprehensive review synthesizes 5,000 years of documented applications from ancient Siddha palm-leaf manuscripts to modern randomized clinical trials validating diverse bioactive constituents including azadirachtin, nimbin, nimbidin, quercetin, and limonoids across leaves, bark, seeds, gum, and oil. Neem extracts demonstrate robust efficacy against Staphylococcus aureus, cisplatin nephrotoxicity, Plasmodium falciparum, gastric ulcers, radiodermatitis, and cervical neoplasia through multifaceted mechanisms encompassing antioxidant protection, apoptotic induction via caspase activation/PARP cleavage, immunomodulation (CCR5 restoration, Treg suppression, NLGP-mediated DC maturation), and ecdysone suppression yielding insect sterility. Aquaculture applications highlight phytogenics outperforming synthetic antibiotics in Aeromonas hydrophilia/Streptococcus resistance while optimizing FCR through MOS/protease synergies. Clinical evidence confirms neem oil's superiority in chemo-radiotherapy dermatitis management and NLGP's IDO inhibition in stage IIIB malignancies. As sustainable alternatives minimizing allopathic side effects via cellular pathway modulation, neem bridges traditional wisdom with evidence-based medicine, warranting Phase III trials and optimized nanoparticle delivery systems for global health/agricultural applications.