Study of anti-anxiety activity of Nicotiana tabacum and Humulus lupulus extracts on Danio rerio fish in the "Novel Tank" test

Ekaterina Alexandrovna Morozova; Морозова Екатерина Александровна; Yulia Konstantinovna Isayeva; Исаева Юлия Константиновна; Anna Igorevna Bradik; Брадик Анна Игоревна; Ludmila Ivanovna Lashchenova; Лащенова Людмила Ивановна; Valentina Nikolaevna Perfilova; Перфилова Валентина Николаевна

Study of anti-anxiety activity of Nicotiana tabacum and Humulus lupulus extracts on Danio rerio fish in the "Novel Tank" test

Authors: Morozova E.A.¹, Isayeva Y.K.¹, Bradik A.I.¹, Lashchenova L.I.¹, Perfilova V.N.¹
Affiliations:
1. Volgograd State Medical University
Issue: Vol 14 (2025): Материалы XXI Международного Бурденковского научного конгресса 24-26 апреля 2025
Pages: 380-382
Section: Фармакология
URL: https://new.vestnik-surgery.com/index.php/2415-7805/article/view/10466

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Abstract

Modern society is facing increasing levels of anxiety and stress, which requires the development of new pharmacological approaches to treat these conditions. One promising area is the use of plant extracts to reduce stress and anxiety. The aim. To study the effect of Nicotiana tabacum and Humulus lupulus extracts on the behavior of Danio rerio fish under chronic stress using the "Novel Tank" test. Materials and methods. The study was carried out on five groups of fish: "Intact", "Stress", "Stress + Hop Cone Extract", "Stress + Dried Tobacco Extract", "Stress + Fluoxetine". The substances were received when the fish were immersed in a solution of a given concentration before the onset of stress. The stressors were applied for a week in the morning and evening, after which the behavior of the fish was evaluated in the "Novel Tank" test. Results. Fish receiving tobacco extract had reduced disorderly movements and freezing episodes and increased latency period before moving to the top of the tank compared to the control group. Conclusion. Nicotiana tabacum extract showed a pronounced anti-anxiety effect, which confirms its promise for further studies. It's superior to Humulus lupulus extract and comparable to fluoxetine in terms of efficacy.

Keywords

anxiolytic activity, stress, Danio rerio, Nicotiana tabacum, Humulus lupulus

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Introduction. Modern society is faced with increasing levels of stress, anxiety and depressive disorders, which requires the development of new approaches in the treatment of these conditions. One of the mechanisms of development of these diseases is disorders of neurotransmitter activity, in particular, imbalance in the serotonin and noradrenaline system, which play a key role in the regulation of mood and emotional state. To study behavioural disorders under stress, the Danio rerio fish model is often used, due to the high sensitivity of their nervous system to external influences and the similarity of some processes occurring in the human brain [1]. The extract of common tobacco (Nicotiana tabacum) due to nicotine content has an activating effect on acetylcholine receptors, thus improving emotional state [2, 3]. Curly hops (Humulus lupulus) containing flavonoids and hop acids, which are known for their calming and anxiolytic effects, making them promising for reducing anxiety and stress [4]. Therefore, the study of extracts of these plants is relevant in the context of finding safe drugs to reduce anxiety.

Aim of the work: To study the effect of Nicotiana tabacum and Humulus lupulus extracts on the behaviour of Danio rerio fish in the ‘Novel Tank’ test after exposure to chronic stress.

Materials and Methods of Study. The model test systems were divided into 5 groups: 1. ‘Intact’ (n=16); 2. “Stress” (control) (n=15); 3. “Stress+Hop cone extract (HCE)” (n=15); 4. “Stress+Dried tobacco extract (DTE)” (n=13); 5. “Stress+Fluoxetine” (n=14). Groups 2-5 were subjected to stressor effects: being in the air, chase with a net, predator exposure, social isolation, low water level, crowdedness, temperature increase for 1 week 2 times a day. The investigated substances were administered by immersing fish for 60 min in a 1-litre tank before applying stressors in the morning. Concentrations of substances: HCE - 8 mg/l, DTE - 16 mg/l, fluoxetine - 0.1 mg/l. Animals from the control group were placed in a glass with dechlorinated water. On day 8 of the experiment, behaviour in the 'Novel Tank' test was investigated. The setup was a trapezoidal tank visually divided into 2 horizontal parts. The experiment was recorded using a webcam for 6 min for each fish. Delayed movement to the top of the tank, time spent at the top of the tank, number of indiscriminate movements, number of freezing episodes, and duration of freezing were evaluated. Statistical processing of the obtained data was carried out using Prism GraphPad programme.

Results of the study. It was found that the latent period before moving to the upper part of the tank in fish of the ‘Stress’ group was 1.9 times shorter than in the ‘Intact’ group (p<0.0001). In the ‘Stress+DTE’ group the index was 1.7 times longer compared to the ‘Stress’ group (p<0.0001), in the ‘Stress+HCE’ group it practically did not differ from the control group, in animals receiving fluoxetine it was 1.6 times longer than in the ‘Stress’ group (p<0.05). Delayed movement may be related to a defensive response to potential danger, being in the benthic part of the tank is more favourable.
The number of indiscriminate movements in the Stress group was 2.2 times higher than in intact fish (p<0.0001). In the ‘Stress+DTE’ group this index was 3.8 times lower (p<0.0001), in the ‘Stress+HCE’ group it did not differ, in those receiving fluoxetine - it was 2.5 times lower (p<0.01) than in stressed fish without pharmacological correction.
In the ‘Stress’ group there were no episodes of freezing, whereas in intact fish the index was 0.68±0.2 (p<0.0001). The number of hiccup episodes in the 'Stress+DTE' group was 0.07±0.02, in fish receiving HCE, 0.26±0.08 (p<0.001), and in the comparison drug group, 0.28±0.09 (p<0.001).
The duration of freezing was similar in the groups with the studied substances, the animals receiving fluoxetine were immobile for the longest time.
Constant movement, especially disorderly movement, increased activity may indicate stress or depression-like state, as fish cannot adapt to the new environment and show disturbance of normal behaviour [5].

Conclusion. The results of this study show that Nicotiana tabacum extract has a pronounced anti-anxiety effect on Danio rerio fish under stress conditions, it is superior to Humulus lupulus extract and comparable in efficacy to fluoxetine in some parameters.

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