doi:10.1038/nindia.2013.172 Published online 30 December 2013
Modern medicine is yet to find a cure for neuro-degenerative disorders of old age like Huntington's disease that affects muscle coordination or Alzheimer's disease, the most common form of dementia. Now researchers at the Benaras Hindu University (BHU) in Varanasi report that a possible cure for these might exist in Ayurveda, India's traditional system of healthcare .
Their experiments with fruit flies (Drosophila melanogaster), a widely used genetic model for various human diseases, have provided scientific evidence that two traditional Ayurvedic preparations suppress neurodegeneration. "Our findings are of general significance in view of the increasing burden of neurodegenerative diseases," Subhash Lakhotia, Professor Emeritus at BHU's cytogenetics laboratory, who led the research team, told Nature India.
According to Lakhotia, these diseases result from the failure of protein quality control mechanisms of the cell. He and his colleagues examined two formulations called Amalaki Rasayana (AR) derived from Indian gooseberry (Emblica officinalis) and Rasa-Sindoor (RS), an organo-metallic ash in the form of nano-sized crystals of mercuric sulphide. Both are traditionally used as part of the rejuvenating Rasayana therapy, one of the eight major branches of Ayurveda. These formulations are believed to minimize old age ailments.
In earlier studies, the BHU team had found that food supplemented with 0.5% (weight/volume) of AR or RS promoted a general well-being of fruit flies. They noticed that the Rasayana preparations significantly improved the flies' tolerance to thermal or starvation stresses and enhanced cellular levels of various heterogeneous nuclear RNA-binding proteins which have key roles in gene expression and RNA processing. "Our present study, building upon our previous work, not only provides a more detailed insight into the mode of action of the selected Ayurvedic formulations but also reveals an impressive suppression of neuro-degeneration associated with Huntington's and Alzheimer's disorders in fly models."
The researchers used well-established transgenic fly models for Huntington's and Alzheimer's disorders. For Alzheimer's they used a fly stock carrying four copies of a transgene called GMR-Aβ42 which synthesizes a polypeptide that leads to development of eyes with amyloid plaques characteristic of Alzheimer's. Likewise, for Huntington's, a mutated human gene producing part of the Huntingtin protein with a stretch of 93 glutamine residues was directed to be expressed in developing eyes which showed accumulation of inclusion bodies characteristic of Huntington's disease. In both cases, many of the eye cells died resulting in highly disorganized and damaged eyes.
The experimental larvae of both models were reared on fly-food mixed with AR or RS, while the control larvae were kept on the standard diet of agar, corn meal, sugar and yeast. They found that the Alzheimer's larvae reared on normal food showed a progressive age-dependent severe disruption of their compound eyes, becoming almost completely blind in 10 days. In contrast, AR or RS-supplemented diet suppressed neurodegeneration in the flies' eyes with greatly reduced accumulation of the toxic amyloid deposits in Alzheimer's model or the inclusion bodies in the Huntington's model.
The experiments suggest that AR or RS feeding improves protein homeostasis pathways. This clears toxic protein aggregates from the cells and the source of toxicity itself is eliminated. Inhibition of induced programmed cell death by dietary AR or RS further facilitates survival of neuronal cells that may have otherwise died due to toxicity of the residual protein aggregates. The researchers said neither of these formulations had any adverse side-effects.
"More such studies in other models would not only provide a better understanding of Ayurveda but also better and safe remedies for the increasing burden of inherited and life style disorders", they said.