Potential of neem (Azadirachta indica L.) for prevention and treatment of oncologic diseases.

Throughout time, plants have often displayed medicinal properties that have been underscored. We often derive medicines involved in treating cancer from components in plants. Azadirachta indica, commonly known as "neem", has been used to treat different ailments in many Asian countries. Due to its widespread beneficial uses, A. indica has often been referred to as "the wonder tree" or "nature's drug store". Various parts of this plant, including, leaves, flowers, fruits, seeds, roots, bark and oil, produce a large number of phytochemicals with various biological and pharmacological activities. The numerous biological activities of the phytoconstituents of A. indica explain its beneficial uses for the prevention and therapy of cancer. The chemopreventive and anticancer therapeutic efficacy of A. indica fractions and compounds could be explained by multiple cellular and molecular mechanisms, including free radical scavenging, carcinogen-detoxification, DNA repair, cell cycle alteration, programmed cell death (apoptosis) and autophagy, immune surveillance, anti-inflammatory, anti-angiogenic, anti-invasive and anti-metastatic activities as well as their ability to modulate several dysregulated oncogenic signaling pathways. This article aims to present the collective and critical analysis of multiple phytoconstituents of A. indica and their molecular mechanisms implicated in cancer chemopreventive and therapeutic effects based on published preclinical and clinical results. Current limitations and future directions of research on this medicinal plant are also critically discussed.