Plants and their chemical compounds affecting β-amyloid and secretase activity as potential sources of neuroprotective herbal medicinal products. Part 1.
Abstract
Plant preparations, especially fractions of biologically active compounds may play an important
role in improving the life quality of patients with diagnosed dementia as well as
delaying the progress of neurodegenerative diseases through various mechanisms of pharmacological
action. Recent years have brought a number of reports on the issue, nevertheless,
it seems that there is still a lack of detailed, synthetical analysis.So far, main biological markers of Alzheimer’s disease pathogenesis which is currently
the most common form of dementia, are the β-amyloid plaques deposits, neurofibrillary
degeneration processes and atrophy of cholinergic neurons in the brain regions crucial for
memory processes maintenance. At present, acetylcholinesterase inhibitors are the main
drugs for the treatment of Alzheimer’s disease. In our previous review article, we pointed
out the interesting mechanisms of action such as inhibition of acetyl-, butyrylcholinesterases
and the antioxidant activity of bio-compounds of selected medicinal plants from
Lamiaceae family (including rosmarinic acid).
The aim of this paper is to systematize the knowledge about the influence of plant extracts
and isolated natural compounds (e.g. cryptotanshinone, epigallocatechin gallate) on the
pathway of β-amyloid formation and deposition in pharmacological models, especially by
interacting with the brain enzyme, α- and β-, γ-secretase or on their genes expression.
This is a long-established trend of research in search of new neuroprotective drugs from
natural sources which raises new therapeutic hopes. Salvia miltiorrhiza and Camellia sinensis,
medicinal plants from Asia, have interesting therapeutic potential in neurodegenerative
disorders. In addition to them, there are known at least 10 Asian plants extensively
researched in this area (e.g. Aralia cordata, Magnolia officinalis, Perilla frutescens, Polygala
tenuifolia, Punica granatum, Sophora flavescens). However, due to the fact that many aspects
of their phytochemical, neurochemical and pharmacological activities are not well known,
further studies should be performed in this field.