NIS - libdoc.who.int - World Health Organization

WHO monographs on medicinal plants commonly used in the Newly Independent States (NIS)
cally removed from the lymph nodes of inbred mice; the final concentration
of cells in culture was 2 × 10 6 cells/ml. The extract was tested at concentrations
ranging from 0.5 to 80 µg/ml; control cells were treated with
saline solution. The lymphocyte proliferation effect was mimicked by Ro
5-4864, a specific agonist of the peripheral benzodiazepine receptor and by
Pk 11195, an agonist/antagonist of the same receptor; these agents were
used as reference standards at a concentration of 5 × 10 -7 M. Maximum
stimulation of 170% was observed at a concentration of 20 µg/ml (p < 0.05).
The synergistic effect of the extract with Ro 5-4864 suggests that the extract
exerted its stimulatory action on cell proliferation by acting as a partial agonist
on peripheral-type benzodiazepine binding sites (56).
Antitumour activity
The antiproliferative action of various extracts: aqueous (1.5 g flowers in
20 ml of water), dichloromethane (9 g flowers in 200 ml of dichloromethane)
and ethanol (9 g flowers in 200 ml of ethanol) of Tilia cordata
flowers on BW 5147 lymphoma cells and non-tumour lymphocytes was
investigated. All extracts (at different concentrations) showed a selective
action on tumour cells, inducing apoptosis. In the case of normal lymphocytes,
these extracts suppressed mitogen-induced proliferation. The
aqueous, dichloromethane and ethanol extracts inhibited proliferation of
tumour and non-tumour cells in a concentration-dependent manner.
From EC 50
values, the dichloromethane extract proved to be the most
active: it showed the greatest inhibition of cell proliferation, as shown by
the EC 50
values for both tumour cells (4.84 µg/ml) and non-tumour cells
(14.12 µg/ml) (p < 0.05). Scopoletin, the main component in the dichloromethane
extract had an antiproliferative action on BW 5147 cells, suggesting
that it may be at least partly responsible for the activity displayed
by this extract (57).
Antimicrobial activity
An aqueous extract of a commercial sample of Flos Tiliae demonstrated
weak antibacterial activity in vitro against Escherichia coli and Staphylococcus
aureus at a median inhibitory concentration (MIC) of 1 mg/ml/
agar plate; Staphylococcus aureus strain Oxford at an MIC of 1.5 mg/ml;
and against Bacillus subtilis at an MIC of 3.1 mg/ml (58).
A methanol extract of the dried flowers exhibited weak antifungal activity
against Aspergillus niger in vitro at a concentration of 5 mg/ml/agar
plate (60).
A 10% aqueous extract of dried Tiliae flowers demonstrated antiviral
activity against influenza virus A2 (Manheim 57) in cell culture (60).
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