NIS - libdoc.who.int - World Health Organization

Folium Salviae
This study was an extension of earlier studies by Yasukawa et al. (81) and
Okuyama et al. (80).
Cholinergic activity
Studies were carried out to evaluate the cholinergic receptor-binding activity
of ethanol extracts prepared from leaves of S. officinalis. Plant extracts
were screened for their ability to displace [ 3 H]-(N)-nicotine from nicotinic
receptors and [ 3 H]-(N)-scopolamine from muscarinic receptors, in homogenates
of human cerebral cortical cell membranes. The most potent extracts,
prepared from three Salvia species had a median inhibitory concentration
(IC 50
) of < 1 mg/ml. The displacement curves of some of these extracts were
comparable with that of carbamylcholine chloride, a potent acetylcholine
analogue. Choline, a weak nicotinic ligand (IC 50
, 3 × 10-4 M) was found in
extracts at concentrations of 10 -6 – 10 -5 M. However, at the concentrations
studied, choline accounted for only 5% of the displacement activity observed.
Although most extracts screened expressed some nicotinic and muscarinic
activity, only a few showed dose-dependent receptor activity typical
of compounds with genuine cholinergic activity (57). Mnemogenic effects of
the ethanol extract from the leaves of S. officinalis (50 mg/kg, administered
intraperitoneally) were tested in rats. Interactions of the extract with the
cholinergic system in memory retention of passive avoidance learning were
investigated. Administration of the extract increased memory retention.
Stimulation of muscarinic and nicotinic cholinoreceptors by pilocarpine (0.5
and 1 mg/rat) and nicotine (0.1 and 1 µg/rat) potentiated the response of the
extract and increased memory retention (F 4,25
= 7.67, p < 0.001) (83).
Neuroprotective effect
The effect of a standardized extract of the leaves of S. officinalis and its
active ingredient rosmarinic acid on Alzheimer amyloid-β peptide (Aβ)-
induced toxic effects in cultured rat pheochromocytoma PC12 cells was
evaluated. Incubation of PC12 cells with Aβ (fragment 1-42) for 24 hours
caused cell death and this effect was reduced by the extract, and by rosmarinic
acid. Rosmarinic acid reduced a number of events induced by Aβ.
These included formation of reactive oxygen species, lipid peroxidation,
DNA fragmentation, caspase-3 activation, and tau protein hyperphosphorylation.
Moreover, rosmarinic acid inhibited p-p38 mitogen-activated
protein kinase, but not glycogen synthase kinase-3 activation. These
data demonstrated a neuroprotective effect of Salvia leaf extract against
Aβ-induced toxicity, which could support the use of this plant in the
treatment of Alzheimer disease. Rosmarinic acid could contribute, at least
in part, to the extract-induced neuroprotective effect (84).
351