Apigenin, a Component of Matricaria recutita Flowers,

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Instituto de BiologIa Celular, Facultad de Medicina, Paraguay 2155 (1121), Buenos Aires, Argentina Instituto de QuImica y Fisicoqulmica Biologicas, Facultad de Farmacia y BioquImica, JunIn 956 (1113), Buenos Aires, Argentina Institute de Investigaciones Biológicas "Clemente Estable", Avda Italia 3318, (11600) Montevideo, Uruguay Address for correspondence
Dried branchiets with flowers of Matricaria recutita were obtained in local herboristeries and their identification was made at the Museum of Botany, Facultad de Farmacia y BioquImica, Universidad de Buenos Aires, by its Director, Dr. J. L. Amorin. A voucher specimen (J. L. A. 3001) was deposited in the Museum.
muscarinic receptors, a1-adrenoceptors, and on the
binding of muscimol to GABAA receptors. Apigenin had
a clear anxiolytic activity in mice in the elevated plusmaze without evidencing sedation or muscle relaxant effects at doses similar to those used for classical benzodiazepines and no anticonvulsant action was detected. However, a 10-fold increase in dosage produced a mild
rameters were evident. The results reported in this paper demonstrate that apigenin is a ligand for the central benzodiazepine receptors exerting anxiolytic and slight
The plant material was crushed in a mechanical mill, and bOg of the resulting powder were suspended in 500 ml of water, boiled for 30mm, and filtered. The aqueous extract was lyophilized, the residue dissolved in a small volume of water, and extracted exhaustively with diethyl ether at pH 5. The collected
An LKB-Pharmacia chromatograph model 2150/
linear gradient of acetonitrile (ACN) in water (10% to 50% in
60 mm), at flow-rates of 1 mi/mm, or 3.5 ml/min, for analytical or semi-preparative runs, respectively. Detection was usually done at 280 nm.
PlantaMed. 61(1995)213—216 © Georg Thieme Verlag Stuttgart New York
ether extracts were evaporated at low temperature and the residue was submitted to reversed-phase high performance liquid chromatography (HPLC) fractionation. The C-I 8 columns used were: 201TP54 (0.46cm x 25 cm; 5 pm particle size; analytical) and 201TP510 (1.0cm x 25cm; 5pm particle size; semi-preparative), both from The Separation Group (Hesperia, CA, USA).
sedative effects but not being anticonvulsant or
myorelaxant.
Key words
Matricaria recutita, Asteraceae, chamomile, flavonoids, apigenin, sedation, anxiolytic effect, exploration, locomotion, convulsions.
sedative effect since a 26% reduction in ambulatory locomotor activity and a 35 % de•crement in hole-board pa-
of the benzodiazepine receptors (BDZ-R) with a K1 of 3 pM (3). Based on the above mentioned findings we decided to investigate the possthle presence of BDZ-R ligands, display-
H. Viola etal.
Table 1 Effects of Lp. administration of diazepam or apigenin on PTZ induced seizures in mice.
doses (mg/kg)a
N° of
% of mice
Binding assays to centralBDZ-B
Received: August 21, 1994; Revision accepted: November 19, 1994
Abstract
The dried flower heads of Matricaria recutita L. (Asteraceae) are used in folk medicine to prepare a spasmolytic and sedative tea. Our fractionation of the aqueous extract of this plant led to the detection of several fractions with significant affinity for the central benzodiazepine receptor and to the isolation and identification of 5,7,4' -trihydroxyflavone (apigenin) in one of them. Apigenin competitively inhibited the binding of flunitrazepam with a K, of 4pM and had no effect 011
washed synaptosomal membranes obtained from bovine cerebral cortex (3) and carried out as described by Medina et al. (4), either under control conditions or in the presence of the inhibitory materials, using 0.5 nM [3H1-Flunitrazepam as tracer. The type of displacement was established in saturation experiments using variable concentrations (0.2 nM— 10 nM) of [3H1-Flunitrazepam. Nonspecific binding was determined in the presence of 3pM Fluni-
ing anxiolytic actions, in aqueous extracts of M. recutita flowers by using a BDZ-R binding assay-guided purification. Materials and Methods Isolation of apigenin
Introduction
The dried flower heads of Matricaria recutita L. (Asteraceae; chamomile), have been reported to
exhibit antiphiogistic, antimicrobial, antiseptic, antifungal, antiherpetic, spasmolytic, and sedative properties. In Europe and in the United States chamomille is highly regarded and is used to prepare one of the most popular herbal infusions