Therapeutic potential of natural products in glioblastoma treatment: targeting key glioblastoma signaling pathways and epigenetic alterations

Glioma is the most common primary tumor of the nervous system, and approximately 50% of patients exhibit the most aggressive form of the cancer, glioblastoma. Currently, considerable research in glioblastoma therapeutics is aimed at developing vaccines or drugs to target key molecules for combating this disease. Studies on plant natural products from spices, vegetables, fruits, teas, and traditional medicinal herbs display that these plant-derived natural products can act as effective antioxidant and anti-tumor agents. The advancements in metabolomics and in genomics have enabled researchers to better evaluate the potential use of immunomodulatory natural plant products for treatment of different cancerous diseases. The glioblastoma protective activities of the different natural plant products lie in their effects on cellular defenses such as antioxidant enzyme systems, detoxification and the stimulation of anti-inflammatory, anti-metastasis responses and by modifying epigenetic alterations, often through targeting specific key transcription factors such as activator protein, nuclear factor kappa B, signal transducers and activators of transcription and so on. Here, we review recent knowledge on the molecular mechanisms by which different inflammatory activities are linked to progression of glioblastoma and the particular immunomodulatory plant products that may reduce inflammation and the associated progression and metastasis of glioblastoma both in vitro and in vivo. Furthermore, their impact on the epigenetic alterations will also be discussed.