Pharmacological studies of neutral saponins (GNS) of Panax Ginseng root.

Pharmacological studies of neutral saponins (GNS) of Panax Ginseng root, were performed. GNS showed CNS-depressant action in inhibition of spontaneous and exploratory movements, and in potentiation of CNS-depressant. A specific blocking action of conditioned response by GNS was significantly confirmed in small doses and did not produce loss of righting reflex, motor incoordination or myorelaxation. Analgesic, anticonvulsant and antipyretic effects were recognized. From the tests described above in addition to those of traction, hypothermia, fighting behavior and ratio of two reflexes, GNS appears to have neuroleptic activity. There was neither hemolytic nor vasodilator action on the hind leg or coronary vascular beds. It is said that the Chinese medicine Ginseng root has some effect on the central nervous system and several reports concerning neuropharmacological properties of Ginseng root have so far been published (1-7). Stimulant action was proved by Brekhman and his co-workers with mice swimming in water (1), and running up an endless rope (2). Petkov (7) also reported the stimulant effect of water-alcohol extracts on the central nervous system and analeptic activity, while on the contrary, antialarm action has also been reported (3-6). In our laboratory, a number of relatively simple tests were employed to obtain a pharmacological spectrum of the activity of extracts, which had been supplied from Shibata et al. (8). From these results, a crude saponin fraction (G. NO. 3) and GNS, a mixture of neutral saponins, were estimated as having neuroleptic activity (9, 10). The present study is an attempt to investigate neuroleptic properties of GNS. MATERIALS AND METHODS GNS is a mixture of neutral saponins mainly composed of Ginsenoside-Rb1, -Rb2 and -Rc. Details of the separation have been described by Shibata et al. (8). The solution of GNS was prepared with physiological saline with the following methods being employed : 1) Acute toxicity in mice Male mice (ddy-strain), weighing 18-21 g, were used and the intravenous, intraperitoneal and oral LD,,, were determined. Mortality was recorded 72 hr after administration. Intraperitoneal and oral LD50 were calculated by the method of Behrens-Karber (11). Intravenous LD50 was done by the up and down method. H. NABATA, H. SAITO & K. TAKAGI 30 2) Hemolytic test The hemolytic effect of GNS was observed using rabbit blood following the method described by Fujita et al. (12). Pure saponin (Merck) was used as a control and hemolytic index was calculated. 3) Motor activity in mice A hole cross test described by Takagi et al. (13), was employed for the measurements of motor activity. A group of 10 male mice, weighing 18-20 g, was placed in the test cage 30 min after administration of the drug. Counting for a group was continued for 1 hr and recorded as a percent of the control value counted for the same group administered saline i.p. at the same time the day before the test. 4) Climbing test in mice The effect of GNS on exploratory movement was observed by the method of Sandberg (14). A group of 10 male mice, weighing 18-20 g, was placed in the test cage for 10 min and the number of animals climbing the net was counted. Drugs were given i.p. before the test. 5) Motor incoordination in mice 1) Rotating rod, 2) sliding angle and 3) spring balance tests described by Takagi et al. (15), were employed for the measurements of motor incoordination and relaxation of muscle tone. Male mice in groups of 8, weighing 18-20 g, were tested foll owing i.p. administration. 6) Traction test in mice Groups of 5 male mice, weighing 18-20 g, were suspended by the forepaws to a metallic wire, and the number of animals incapable of touching the wire with at least one of the hindpaws within 5 sec after placement on the wire was recorded. Tests were done 4 times: 30, 60, 90 and 120 min after i.p. administration of GNS. 7) Potentiation of hypnotic action of hexobarbital in mice Groups of 10 mice, weighing 22-26 g, were given GNS i.p., and 30 min later 70 mg/ kg of hexobarbital sodium was injected via the same route. Duration of loss of the righting reflex was measured. 8) Analgesic tests in mice i) Writhing induced by 0.7% acetic acid Male mice in groups of 6, weighing 20-23 g, were given GNS orally, and 30 min later an i.p. injection of 0.7 % acetic acid. The number of writhings per mouse was recorded for a period of 10 min, beginning 10 min after administration of acetic acid. ii) Tail pressure test The method used was as described by Takagi et al. (16). Groups of 5 male mice, weighing 18-20 g, were tested after i.p. administration of GNS. 9) Anticonvulsant test in mice i) Convulsions induced by electroshock Groups of 10 male mice, weighing 18-20 g, were given test substances orally, and 30 min later subjected to the maximum electroshock (Corneal electrodes with 25 mA and PHARMACOLOGY OF PANAX GINSENG ROOT 31 0.17 sec), in order to observe tonic extension of hind legs and death. ii) Convulsions induced by chemicals Male mice in groups of 10, weighing 22-26 g, were given the test compound i.p. 30 min before automatic i.v. infusion of pentylenetetrazol (0.05 %), strychnine sulfate (0.01 %) and nicotine tartarate (0.08 %) given at a rate of 0.33 ml/sec. Two end-points were taken : the first appearance of convulsion, and death. 10) Hypothermia in mice Groups of 10 male mice, weighing 22-26 g with 37-38°C rectal temperature, were given the test substance by the i.p. route and rectal temperature was recorded every 30 min for 2 hr at room temp. of 25•Ž. 11) Antipyretic test in mice Male mice in groups of 10, weighing 22-26 g with 37-38•Ž rectal temperature, were given the test substance i.p. 30 min after i.v. administration of TTG (pyrogen, Fujisawa Chemical Industry Co. Ltd.) in a dose of 100 ƒÊg/kg, and rectal temperature was recorded every 30 min for 4 hr. Aminopyrine was used as a control. 12) Ratio of reflexes in mice This method was described by Witkin et al. (17). Groups of 10 male mice, weighing 18-20 g, were given GNS by the i.p. route. Corneal and pinna reflexes were tested using