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Azamatov Azizbek Azamat o'gli, Junior Scientific Researcher of Department of Pharmacology and Toxicology of Institute of Chemistry of Plant Substances, Academy of Sciences of Republic of Uzbekistan, Tashkent
Rejepov Jumadilla,
Leading Scientific Researcher of Department of Pharmacology and Toxicology of Institute of Chemistry of Plant Substances, Academy of Sciences of Republic of Uzbekistan, Tashkent
Tursunkhodjaeva Firuza Muratovna, Senior Scientific Researcher of Department of Pharmacology and Toxicology of Institute of Chemistry of Plant Substances, Academy of Sciences of Republic of Uzbekistan, Tashkent,
E-mail: [email protected]
Rakhimov Shukhrat Berdukulovich, Senior Scientific Researcher of Alkaloids Chemistry Laboratory of Institute of Chemistry of Plant Substances, Academy of Sciences of Republic of Uzbekistan, Tashkent Vinogradova Valentina Ivanovna, Senior Scientific Researcher of Alkaloids Chemistry Laboratory of Institute of Chemistry of Plant Substances, Academy of Sciences of Republic of Uzbekistan, Tashkent
ANTIXYPOXANT, ANTI-NARCOTIC ACTIVITY AND ACUTE TOXICITY OF N-METHYLCYTISINE
Abstract: Nootropic drugs are widely used in disorders of cerebral circulation, cranio-cerebral trauma, diseases of the central nervous system accompanied by a decrease in intellectual and mnestic functions, Alzheimer's disease, brain function disorders caused by alcoholism and drug addiction, in acute alcohol and narcotic drugs poisoning, and acute neuroinfections. Recent years, in many countries of the world, derivatives of quinolizidine alkaloid cytisine are positioned for treatment of the mentioned disorders. The aim of this work is to study the antihypoxant, anti-narcotic activity and toxicity of N-methylcytisine. N-methylcytisin has a stimulating effect on the central nervous system, increases the motor-orientation and exploratory reactions, shown a pronounced antihypoxant and antinarcotic effect equal to those of Piracetam.
Keywords: N-methylcytisine, antixypoxant, anti-narcotic activity, acute toxicity.
Introduction clinical studies, improve the neurological outcome, but do
Recent years, neurodegenerative diseases (NDDs) are not reduce the lethality in such diseases [8, 131-136]. In diagnosed in 50-75% of the world population [1, 492-494] this regard, the development, creation and implementation and have become a serious problem of healthcare [2, 4, of new effective and safe drugs for the prevention and treat-19-23]. Nootropic drugs are widely used in complex treat- ment of NDDs are the urgent tasks [9, 26-47]. Recent years, ment of NDD. They are prescribed in disorders of cerebral in many countries of the world, derivatives of quinolizidine circulation, cranio-cerebral trauma, diseases of the central alkaloid cytisine are positioned for the treatment of NDDs nervous system accompanied by a decrease in intellectual [10,1256-1262; 12, 555-567].
and mnestic functions, Alzheimer's disease, brain function The Pilot manufacture of academician S. Yu. Yunusov
disorders caused by alcoholism and drug addiction, in acute Institute of the Chemistry of Plant Substance, Academy of alcohol and narcotic drugs poisoning, and acute neuroinfec- Sciences of Uzbekistan every year processed tens tons of tions [5, 169; 7, 675]. Thermopsis alterniflora to produce cytisine [13, 50]. The sum
Despite advances in the development of drugs for NDDs of alkaloids from Thermopsis alterniflora along with cytisine therapy, the most of them, according to results of multicenter contains up to 60% N-methylcytisine [14, 33-56].
The aim of this work is to study the antihypoxant, anti-narcotic activity and toxicity of N-methylcytisine.
Antihypoxant activity of N-methylcytisine was compared with Piracetam, the drug with a pronounced nootropic effect. Antihypoxant activity is the most important manifestation of Piracetam action.
Materials and methods of research. The effect on the CNS physiological activity was studied in an open field device. Behaviour changes of the experimental and control animals were observed during 2 minutes. The number of horizontal movies along the number of intersected squares, the number of stands on the hind legs, and the number of the surveyed holes were recorded. The mean values ofthe parameters for the group were calculated. All animals before the experiment were kept in the same conditions with free access to water and food.
N-methylcytisine was administered subcutaneously at doses of 1-2.5-5 mg/kg for 30 minutes before the starting of experiment. Each dose was tested on 10 mice. The sterile water for inj ection was administered to control group of animals under the same experimental conditions.
Antihypoxant activity was studied in experiments on white male mice on the model of normobaric hypoxia with hypercapnia. Mice of the same mass were placed one by one in 250 cm3 hermetic cans, the survival time (reserve time) of
the animals was recorded under hypoxia conditions, and the percentage of the reserve time increase was counted relative to the control group.
The analeptic effect of N-methylcytisine in ethanol (24% -6 g/kg intraperitoneally) and sodium ethaminal (0.4% - 40 mg/kg intraperitoneally) intoxication was evaluated in mice. The substance was administered in doses of 1-2.5-5 mg/kg subcutaneously for 30 minutes before ethanol and ethaminal sodium introduction.
The acute toxicity was studied on white mice in subcutaneous application of the substance. The mean lethal dose was determined using the Litchfield-Wilcoxon method [15].
Neurotropic and antihypoxant activity of N-methylcy-tisine in all experiments was compared with Piracetam at a dose of 400 mg/kg.
Results and discussion
In the abovementioned studies N-methylcytisine showed high stimulating activity. The drug at a dose of 1 mg/kg and 2.5 mg/kg significantly increased locomotor activity in open field, increased the spontaneous locomotor activity of mice in squares crossed horizontally, the number of stands on hind legs and the number of examined holes. In a dose of dose 5 mg/kg, the substance had no stimulating effect (Table 1).
Table 1. Effects of N-methylcytisine on mice orientational and exploratory behavior in the open field
№ Animals group Horizontal movies number Number of stands on hind legs Holes examination
1. Control 15.6 (9.4 * 23.8) 2.4 (1.8 4 3.2) 3.5 (2.2 4 5.0)
2. Piracetam 400 mg/kg 22.4 (15.4 4 31.0) ON 1 3. 4.6 (4.1 4 5.2)
23.1 3.0 4.4
N-methylcytisine (16.0 4 32.1) (2.3 4 3.8) (3.8 4 5.3)
3. 1 mg/kg 27.2 3.8 4.5
2.5 mg/kg (20.2 4 36.4) (3.0 4 4.7) (3.6 4 5.5)
5 mg/kg 16.0 2.0 3.1
(9.0 4 24.4) (1.5 4 2.5) (2.5 4 37.8)
Experiments on the study of antihypoxant activity of N-methylcytisine on the model of normobaric hypoxia with hypercapnia showed a distinct protective effect of the substance, Table 2.- Mice survival in the conditions
which was expressed in an increase in the reserve survival time relatively to the control group of mice and Piracetam
(Table 2).
of normobaric hypoxia with hypercapnia
№ Animals group Survival time, min. Survival time increase,%
1 2 3 4
1. Control 33.5 (32.6 4 34.6) -
2. Piracetam 400 mg/kg 38.7 (37.5 4 40.0) 15.5
1 2 3 4
3. N-methylcytisine 1 mg/kg 2.S mg/kg 5 mg/kg 46.2 (45.3 - 47.3) 37.9
4S.S (47.6 - 50.2) 45.6
31.9 (30.9 - 33.0) - 4.S
As seen from (Table 2), N-methylcytisin at doses of 1.0-2.5 mg/kg had a good protective effect, increased the reserve survival time relative to the control group of mice by 37.9 and 45.6%, respectively, and compared to piracetam -by 12.2 and 20.7%.
Table 3.- N-methylcytisine antinarcotic effects in
The results of N-methylcytisine antinarcotic effects in ethyl alcohol and ethaminal sodium intoxication are presented in (Table 3).
ethyl alcohol and ethaminal sodium intoxication
Introduced substance Dose, mg/kg Duration of narcosis (min.) caused by
ethanol ethaminal sodium
Control (water) 0.2 ml 10S.6 102
N-methylcytisine 1 mg/kg 54.2 105
2.5 mg/kg 36.2 53.7
5 mg/kg 34.9 40.S
In the control group, intraperitoneal application of etha-nol at a dose of 6 g/kg causes narcosis (sleeping in lateral position) with an average duration of 108 minutes in all animals. Preliminary subcutaneous application of N-methylcytisine reduced ethanol narcosis duration for two times at a dose of 1 mg/kg, and for three times at doses of 2.5-5.0 mg/kg in compare to the control group.
In the second series of experiments the intraperitoneal administration of ethaminal sodium (control) at a dose of 40 mg/kg in all control mice causes an narcosis average for 102 minutes. Preliminary subcutaneous administration of N-methylcytisine at a dose of 1 mg/kg did not significantly affect the duration of sleeping in lateral position. At a dose of 2.5 mg /kg, it had an analeptic effect and reduced the narcotic state
for 1.9 times. At a dose of 5 mg/kg N-methylcytisine reduced the duration of the lateral position of the mice for 2.5 times as compared to the control group.
N-methylcytisine acute toxicity in mice (LD50) in subcutaneous administration was 38 (33.6 ^ 42.9) mg/kg, in oral administration 145 (127.1 ^ 165.3) mg/kg.
Conclusion
1. N-methylcytisin has a stimulating effect on the central nervous system, increases the motor-orientation and exploratory reactions.
2. It has a pronounced antihypoxant and antinarcotic effect.
3. Antihypoxant and antinarcotic activity of N-methylcytisine is equal to those of Piracetam.
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