Alzheimer's disease is a progressive neurodegenerative disorder primarily manifesting as a loss of memory. Alzheimer's disease is without doubt one of the most terrible afflictions of late-middle age to old age. It has often been termed 'brain failure'. Others have referred to it as amentia - death of the mind.

First of all it should be said that diagnosis is a problem. There are often confounding factors. Frequently there is some Parkinsonism. Often there is exogenous depression. In most cases the only certain diagnosis is post-mortem. Here the classical signs are neurofibrillary tangles (NFTs) in cortical pyramidal cells and elsewhere; areas of degerating neurites known as plaques; single electron-dense granules within neuronal perikarya termed granulovacuolar degeneration (GVD); rod-shaped eosinophilic inclusions known as Hirano bodies. In addition the gross appearance of the brain shows considerable atrophy and an enlargement and coarsening of the sulci.

The condition appears to be restricted to humans and perhaps the higher primates. This makes it difficult to study because there are no good animal models.

There are a few questions which need to be thought over:

• Is it an inherited condition?
• Is there an environmental cause?
• Could it be due to an infective agent?
• Is it due to the degeneration of a particular population of neurons?
• Could it be due to a breakdown of the blood-brain barrier and some autoimmune reaction?

Use of therapeutic agents based on the putative pathogenic etiology of the disease such as excitotoxicity, amyloidosis, aluminium accumulation, inflammatory mechanisms and free radical production is being evaluated.

HERBAL REMEDIES

Memory Tonic is a herbal tea with the following ingredients: Melissa officinalis, Rosmarinus officinalis, Ginkgo biloba, Salvia officinalis, Centella asiatica, Panax Ginseng, Eleutherococcus senticosus, Thymus vulgaris, Zingiber officinale, Avena sativa and Withania somnifera.

Ginkgo biloba is a plant extract used to alleviate symptoms associated with cognitive deficits, e.g., decreased memory performance, lack of concentration, decreased alertness, tinnitus, and dizziness. Pharmacologic studies have shown that the therapeutic effect of ginkgo is based on several active constituents with vasoactive and free radical-scavenging properties.

Salvia officinalis and Melissa officinalis have been found to have cholinergic activities(Perry, E.K. et al. 1998, 1999).

Active glycowithanolides of Withania somnifera have significant antioxidant function which is accomplished by increasing the activities of superoxide dismutase, catalase and glutathione peroxidase(Bhattacharya, S.K., et al. 1997).

Withania somnifera has cognition-enhancing and memory-improving effects. These effects could be partly explained because extracts from the plant caused an increase in cortical muscarinic acetylcholine receptor capacity (Schliebs, R., et al. 1997).

RESEARCH

Clinical trials on ginkgo biloba showed an effect on cognitive symptoms was within the range of a 25% reduction. Memory, concentration, and alertness were the first symptoms to be relieved, with tinnitus and dizziness improving somewhat later. A minimum of 4 to 6 weeks were needed before a pronounced effect could be expected (Soholm, B. (1998).

In Alzheimer's disease, there is degeneration of cholinergic neurons in Meynert's and other brain stem nuclei. Salvia officinalis and Melissa officinalis have been found to have cholinergic activities(Perry, E.K. et al. 1998, 1999).

Active principles of Withania somnifera increased the activities of superoxide dismutase, catalase and glutathione peroxidase. Results were comparable with effects induced by deprenyl, an agent with well documented antioxidant activity (Bhattacharya, S.K., et al. 1997).

Sitoindosides VII-X and withaferin-A from Withania somnifera enhanced M1-muscarinic cholinergic receptor binding in lateral and medial septum as well as in frontal cortices, whereas the M2-muscarinic receptor binding sites were increased in a number of cortical regions including cingulate, frontal, piriform, parietal and retrosplenial cortex. (Schliebs, R., et al. 1997).

REFERENCES

Bhattacharya, S.K., Ashok, Kumar Shibnath, Ghosal (1995). Effects of glycowithanolides from Withania somnifera on an animal model of Alzheimer's disease and perturbed central cholinergic markers of cognition in rats. Phytotherapy Research. 9(2);110-113.

Bhattacharya, S.K., Satyan, K.S., Ghosal, S. ((1997). Antioxidant activity of glycowithanolides from Withania somnifera. Indian J.Exp.Biol.35(3);236-9

Perry, E.K., Pickering, A.T., Wang, W.W., Houghton, P.J. and Perry, N.S. (1998). Medicinal plants and Alzheimer's disease: Integrating ethnobotanical and contemporary scientific evidence. J. Altern. Complement. Med. 4(4):419-28.

Perry, E.K., Pickering, A.T., Wang, W.W., Houghton, P.J. and Perry, N.S. (1999).Medicinal plants and Alzheimer's disease: from ethnobotany to phytotherapy. J. Pharm. Pharmacol. 51(5):527-34.

Schliebs, R., Liebmann, A., Bhattacharya, S.K., Kumar, A., Ghosal, S. and Bigl, V. (1997). Systemic administration of defined extracts from Withania somnifera (Indian Ginseng) and Shilajit differentially affects cholinergic but not glutamatergic and GABAergic markers in rat brain. Neurochem. Int. 30(2):181-90.

Soholm, B. (1998). Clinical improvement of memory and other cognitive functions by Ginkgo biloba: review of relevant literature. Adv. Ther. 15(1):54-65.

Vance, D.E., Ehmann, W.D. and Markesbery, W.R. (1988). Trace element imbalances in hair and nails of Alzheimer's disease patients. Neurotoxicology. 9(2); 197-208.

HERBAL BLESSINGS
Georges-Louis Friedli, PgDip., MSc., CHt., RH., PhD.
drfriedli@friedli.com