Scientific basis for the anti-dementia drugs of constituents from Ashwagandha (Withania somnifera)(Chemical & Pharmacological study)

Although Ashwagandha (root of Withania somnifera) has been used for multi purposes but mainly as a tonic in the traditional Indian Ayurvedic medicine, this review focused on nootropic effects of Ashwagandha itself and isolated compounds from it. Several reports showed sitoindosides VII-X as active compounds for cognitive enhancer. However, our study revealed other active constituents, withanolide A, withanoside IV and withanoside VI, could improve Aβ(25-35) induced memory impairment, neuronal atrophy and synaptic loss in the cerebral cortex and the hippocampus. Treatment with Aβ(25-35) induced axonal and dendritic atrophy, and pre-synaptic and post-synaptic losses also in cultured rat cortical neurons. Subsequent treatment with withanolide A, withanoside IV and withanoside VI induced significant reconstruction of pre-synapses and post-synapses, in addition to regeneration of both axons and dendrites in the neurons. Withanolide A, withanoside IV and withanoside VI are therefore important candidates for the therapeutic treatment of neurodegenerative diseases, as it is able to reconstruct neuronal networks.Century COE program, Toyama Medical and Pharmaceutical Universit