Pritha Chatterjee : New Delhi, Tue Apr 02 2013, 02:10 hrs
It's a disease long associated with the elderly but is now diagnosed in younger people as well and with no permanent cure available till date.
However, in what could give hope to thousands suffering from Alzheimer's Disease (AD), the pharmacology department in AIIMS has identified Ayurvedic drugs which could have a role in preventing the onset of AD and also restricting its spread in affected patients.
AD is a degenerative neurological disorder leading to progressive loss of cognitive abilities, including the patient's memory due to a drop in chemicals — known as neurotransmitters — which transmits messages between brain cells.
The latest of these studies has been published in international journal Neurochemistry International, where symptoms of Alzheimer's were induced in rats by injecting them with a chemical, streptozotocin, which replicates the clinical symptoms of the disease.
When these rats were treated with the herb Shankpushapi or Evolvulus alsinoides, the cognitive functions of rats improved.
Joginder Mehla, who has been following therapeutic options for AD as part of his PhD project, said the rats showed functional improvement in areas like memory, aggression, mood swings, ability to think and take decisions, and lack of confusion.
Last year, the institute was also able to establish similar therapeutic effects of another Ayurvedic drug — Aparajita or Clitoria ternatea.
In Alzheimer's patients, there is a cascade of biochemical changes in the brain triggered by the release of free radicals that destroy the neurons, by a vicious cycle of exciting amino acids and releasing calcium.
Dr Y K Gupta, HoD of the pharmacology and the corresponding author of the articles, said, "We found that the herbal drugs control the symptoms of AD in two ways. First, their antioxidant properties are able to control the release of free radicals that damage the brain cells. Secondly, these drugs also inhibit the activity of an enzyme that destroys Acetylcholine — the chemical that acts as a neurotransmitter."
In normal people, the body naturally replenishes this neurotransmitter through a cyclic process, after the enzyme Acetylcholinesterase destroys it. In AD patients, this enzyme destroys the chemical much faster than it can be produced, leading to an unnatural loss of Acetylcholine, Dr Gupta said. Conventional chemical drugs can only supplement the neurotransmitter, but have little role in restricting the activity of the enzyme.
Male Wistar rats, weighing 250-300 grams, were divided into seven groups, including the control and experimental arms, and injected with the chemical streptozotocin to induce AD-like symptoms.
"While we were able to clinically replicate all symptoms of Alzheimer's, two changes which occur in the brain cannot be produced by this chemical. This includes the formation of plaques, or clusters of proteins, and Neurofibrillary Tangles — the twisted strands of another protein in nerve cells," Dr Gupta said.
Doctors said in the long run, there was enough evidence to suggest that the herbal drugs, in isolation or as a supplement to conventional drugs, may help in managing AD as well as other memory disorders .
