INTRODUCTION:

Stress brings various changes in physiological condition of the organism, but various mechanism of the body will counteract to maintain homeostasis. In some situations, body’s adaptation to stress is like reward, which is responsible for improvement of body’s performance beyond its capacity. However if organism suffer strong acute or chronic stress, body is unable to maintain homeostasis. Under this condition, various types of diseases and disorders will develop, and even it may lead to death, if it is not managed at proper time. When the organism is exposed to cold condition of environment, it leads to stress resulting in damage to the body¹. Various diseases and disorders caused by stress are hyperglycemia, elevated blood pressure, gastric ulcers, chronic stress induced depression and suppression of immunity². Environmental stress brings down immunity of organism, which is indicated by rise of stress markers³. Adaptogens are food supplements or medicinal plants acting as antistress agents by improving resistance and tolerance of the body to any stress situation⁴. Adaptogen or antistress agents improve physical and mental working capacity in severe stress circumstances, and improve tolerance of the body to extreme conditions of environment and climate. Adaptogens are like general tonic which enhance health and wellbeing of human body by providing strength and immunity to the body, arresting ageing etc.⁵

An attempt is made to review briefly screening models for evaluation of adaptogenic potential of medicinal agents.

Screening Models for evaluation of adaptogenic activity:

1. Swimming Endurance test:

Purpose and rationale:

In this method, the anti-stress effect of test substance is evaluated by determining the improvement in swimming endurance period and overall performance of the animals, when subjected to swim in restricted space like water vessel.^6,7

Animals:

In this method experimental investigation is carried out using mice of either sex, weighing between 25 to 30 gm as per the guidelines provided by CPCSEA.

Treatment:

Prepare 1% w/v gum acacia in normal saline to be used as vehicle. Suspend the test substance in distilled water containing 1% w/v gum acacia. Suspend Geriforte used as standard drug, in 1%w/v of gum acacia in saline.

Dose selection:

Select the dose of test substance based on body weight of animals. The dose of Geriforte is 100mg/kg body weight of animal. Use the vehicle dose of 10ml/ kg body weight of animal.^8,9

Treatment protocol:

Randomly assign Mice of either sex into groups, each group consisting of six mice as follows:

Group 1: Stress control group- administer vehicle only before subjecting animals for swimming stress

Group 2: standard group, administer with Geriforte at the dose of 100mg/kg body weight of animals and expose them to swimming stress.

Group 3: treatment group 1- administer the test drug (dose 1) and subject to swimming stress

Group 4: treatment group 2- administer the test drug (dose 2) and subject to swimming stress.*

* - Treatment groups for test substance is based on number of dosing strength being evaluated.

Method:

Treat all groups with vehicle, test substance and geriforte by oral route for 10 consecutive days. On 10^th day, expose mice to swimming stress by making them swim in the transparent tub containing water at room temperature. The height and diameter of the transparent tub were 30cm and 25cm respectively. Maintain the water level to the height of 25cm in the transparent tub, so that mice are unable to touch the bottom or escape from the top. The swimming of these mice is not restrained and they are allowed to swim till they are exhausted. The end point of this swimming endurance is drowning and death of the mice. Record the swimming endurance of each mouse by observing duration of survival time, during swimming stress.^10,11

2. Chronic stress model (CS) in Rats.

Purpose and rationale:

This method is based on the principle that immobilization of animals increases their stress response. It activates the hypothalamic pituitary axis to generate increased corticosteroid level that lead to increase in production of cortisol from adrenal gland as a result of it activation of corticosterone. The major advantage of using immobilization as a model of stress is that it produces an inescapable physical and mental stress to which adaptation is seldom exhibited (animal stress model).¹²

Animals:

Experimental investigation is carried out using wistar rats of either sex, weighing between 150 to 200gm. Conduct the experiment in compliance with the guidelines provided by CPCSEA.

Treatment:

Prepare 1% w/v gum acacia in normal saline to be used as vehicle. Suspend the test substance in distilled water containing 1% w/v gum acacia. Suspend Buspiron used as standard drug (10mg/kg), in 1%w/v of gum acacia in saline.

Dose selection:

Select the dose of test substance in mg/kg body weight of animals based on previous reported studies. Use the vehicle dose of 10ml/kg body weight of animal.

Treatment protocol:

Randomly assign Wistar rats of either sex into six groups, and each group consisting of six rats as follows:

Group 1: Control group, administer animals with vehicle and do not subject for chronic stress.

Group 2: Disease control group, administer animals with vehicle (distilled water using 1% w/v gum acacia) and then subjected for chronic stress.

Group 3: Standard group, administered with standard substance i.e. Omeprazole at the dose of 10mg/kg body weight and subject for chronic stress.

Group 4: Administer Wistar rats of this group with test substance at suitable dose (Dose 1) in mg/kg body weight and subjecte for chronic stress.

Group 5: Administer Wistar rats of this group with test substance at suitable dose (Dose 2) in mg/kg body weight and subject for chronic stress.

METHOD:

Select adult male albino wistar rats of 150- 200gm and divide into 05 groups. Each group consisting of 06 animals.

Group 1 serves as a control while group 2 as a positive control (received vehicle. P.o). The group 3 serves as a standard and receives omeprazole 10mg/kg. Group 4 and 5 to be given test compound. Follow the treatment as stated above for 10 days, 1 hour before the exposure of stress. Induce stress by immobilizing rats with head down supine position by fixing fore limbs and hind limbs to a wooden board daily for 2 hour (12pm to 2pm) for a period of 10 days.

Secure and sacrifice rats on operating table and open the abdomen. Incise the anterior abdominal wall muscle of rat using a sharp scalpel. Carefully dissect out the stomach from the body of rat. Open the glandular portion of the stomach along greater curvature and gently rinse with water. Stretch the stomach and pin on soft foam board in such a way that mucosal site remains up. Record the weight of organs, such as liver, spleen, adrenal gland, and testes after washing with phosphate buffer per 10 % weight of organs.¹³

Assessment of ulcer¹⁴

Examine the mucosa under microscope with 10X magnification for evaluation of the numbers of ulcer and severity of ulcer.

Ulcer number: Count thy numbers of ulcers into the stomach.

Ulcer severity score: evaluate the severity of ulcer in the range of 0 to 3 scale. Severity of ulcer scale is as follows.

Stomach without ulcer = score 0

Stomach with superficial ulcers = score 1

Stomach with deep Ulcers = score 2

Stomach with perforation = score 3

Ulcer index: Determine the ulcer index for each rat as follows.

UI = UN+US+UP×10-1,

Where

UI = Mean ulcer index.

UN = Mean ulcer number of rat.

US = Mean ulcer severity score of rat.

UP = Ulcer percentage of rat.

4. Percentage of ulcer protection:

Calculate it as follows

% ulcer protection = (Mean ulcer index of control -Mean ulcer index of test) X 100 (Mean ulcer index of control)

Gastric secretion pH:

Collect the gastric contents by centrifuging it at 1000rpm for 10 min. take the supernatant sample dilute with distilled water and record the pH

Statistical analysis:

The data of investigation is subjected to one way analysis of variance, followed by Dunnet΄s test for comparison between the groups of treatment. Difference with p<0.05 is considered as significant.

CONCLUSION:

There is growing concern for combating stressful situations and its noxious effects on physical and mental health. Various medicinal plants have shown antistress activity such as Ashwagandha, Ginseng, and Tulsi. Many Polyherbal formulations have been developed for the management of stress. The need for effective and safe antistress adaptogenic agents both from synthetic and natural origin is high. This has prompted to carry research on evaluation of adaptogenic and immunomodulating potential of possible candidates in rodents.

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Received on 20.02.2021 Modified on 09.03.2021

Research Journal of Science and Technology. 2021; 13(2):147-150.

DOI: 10.52711/2349-2988.2021.00022