Herb promise for Alzheimer's
doi:10.1038/nindia.2012.19 Published online 13 February 2012
Medicinal shrub Withania somnifera, also known as Ashwagandha or Indian ginseng, has shown promise as a new drug candidate for the treatment of Alzheimer's Disease (AD)1.
Researchers from the National Brain Research Centre (NBRC), Haryana along with colleagues from the Montreal Neurological Institute of McGill University, University of Delhi and Indian Institute of Science, Bangalore have found that semi-purified extracts from the shrub reverses abnormal behaviour as well as the pathology associated with the disease.
Having worked on two different models of transgenic mice carrying mutations seen in familial Alzheimer's disease (AD), they say that further purification of the extract could lead to a potential new class of molecules for the treatment of the neurological anomaly.
Lead scientist Vijayalakshmi Ravindranath of the NBRC says the therapeutic effect was also seen in 22 to 24-month-old mice with AD, a fact not reported before. "The extract also lessened cerebral amyloid angiopathy – the deposition of beta amyloid in the blood vessels," she told Nature India.
In a healthy brain, beta amyloid protein fragments are broken down and eliminated but in AD, they get accumulated to form solid plaques between neurons.
A month-long course of semi puriﬁed extract of the root of W. somnifera reversed behavioral deﬁcits, plaque pathology, accumulation of β-amyloid peptides (Aβ) and oligomers in the brains of middle-aged and old Alzheimer's disease transgenic mice.
The most interesting aspect of the research, Ravindranath notes, is that increase in the expression of a liver protein called LRP (lipoprotein receptor related protein) resulted in pushing out the beta amyloids from the brain into the plasma.
"Since LRPs acts as a sink for beta amyloids, we have a new peripheral drug target for treatment of AD," Ravindranath points out.
- Sehgal, N. et al. Withania somnifera reverses Alzheimer's disease pathology by enhancing low-density lipoprotein receptor-related protein in liver. Proc. Nat. Acad. Sci. USA doi: 10.1073/pnas.1112209109 (2012)