Nanotechnology-enabled phytochemicals from Ayurvedic herbs for the treatment of neurodegenerative disorders: an overview

Neurodegenerative disorders (NDs) such as Parkinson's, Huntington's, and Alzheimer's disease associated with an abnormal buildup of proteins are a huge challenge to public health and a financial burden, globally. The complex pathophysiological mechanisms, including the presence of numerous protective barriers (such as the blood-brain barrier (BBB)) and rapid hepatic/renal/mucosal clearance of systemic applied drugs, lead to the failure of conventional therapies against NDs. Moreover, synthetic and semisynthetic drugs, despite short-time reliefs, are implied in neurotoxicity and peripheral side effects. Ayurvedic medicine from ancient India is one of the world's oldest holistic healing systems that involve phytochemicals from medicinal herbs to combat diseases. Over the years, Ayurvedic herbs, including but not limited to Madhurika (Foeniculum vulgare), Kumari (Aloe barbadensis miller), Haritaki (Terminalia chebula), Nimba (Azadirachta indica), Kokum (Garcinia indica), Tila (Sesamum indicum), and Shatavari (Asparagus racemosus) have been proven to have neuroprotection properties. Although the phytochemicals showed greater efficiency and lower toxicity in vitro, the lack of efficacy in breaching BBB reduced their bioavailability at the target site and, thus, their effectiveness in vivo. Nanotechnology that deals with particles at the nanoscale range has shown immense potential in drug development and delivery over the years. Nano-enabled strategies for site-specific delivery of phytochemicals from Ayurvedic herbs hold enormous potential in ND treatment. This chapter focuses on the current treatment paradigm against ND and the potential of nanotechnology in the Ayurvedic treatment of NDs.