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Titre : Pharmacological Screening of Selected Sudanese Medicinal Plants for Analgesic, Antinociceptive, Antipyretic and Sedative Effects

Auteur : Muna Gafaar Idris Nabag

Université de soutenance : University of Khartoum

Grade : Ph.D. in Pharmaceutical Sciences (Pharmacology) 2022

Résumé partiel
Plant-based therapies are widely used in Sudan and around the world. Acacia gerrardii Benth (السلجم), Asparagus flagellaris (Kunth) Baker (السريح) and Tephrosia uniflora Pers (عرق التيس) from Eastern Nuba mountains are frequently used in folk medicine for many ailments including pain. The current study aimed to assess the analgesic, antinociceptive, antipyretic and sedative effects of the above-mentioned plants. Acute oral toxicity of the extracts was also investigated by determining the LD50. ● Methods : Dichloromethane and ethanolic extracts of the leaves and roots of the selected plants were tested in albino rats of both sexes weighing (110- 210g). For each test 17 groups of rats ( n=6) were used, the doses were (100, 200, and 400 mg/kg orally) from each extract in each of the tests and normal saline 10ml/kg used as control. Extracts were investigated for analgesic and antinociceptive activities using the acetic acid-induced writhing test, formalin-induced paw licking test, tail flick method and hot plate method. Morphine (5mg/kg) was used as standard drug. The mechanism of action elucidated through pre-treatment with naloxone (1 mg/kg) in hot plate test for the ethanolic extracts of A. flagellaris. Sedative effect was examined by open field test and hole board tests and diazepam (1mg/kg) was used as standard drug. The antipyretic effect of the selected plants was evaluated by Brewer’s yeast test, and paracetamol (150mg/kg) was the standard drug. Ethanolic extracts were tested for acute oral toxicity. Firstly three groups (n=3) were fed with single oral dose of the extract (10, 100, and 1000 mg/kg), when no mortality after observation for 24 hours a second test carried for three groups (n=1) for doses of (1,600, 2,900, and 5000 mg/kg). The animals were closely observed for any general and behavioral changes for 24 hours, and then LD50 value was calculated. Data analysis : Results were calculated as mean ± standard error of the mean, by using one-way ANOVA flowed by Tukey post hoc test in SPSS. P value (p<0.05) was considered significant. ● Results : Ethanolic extract A. flagellaris leaves (400mg/kg) recorded 87.92% (p≤ 0.001) in acetic acid writhing, 86.51% and 79.89% (p≤ 0.001) in early and late phases of formalin test respectively, while ethanolic extract A. flagellaris roots exhibited the highest retention 14.97±0.19 seconds at 120 minutes (p≤ 0.001) in the tail flick test. In hot plate test, the highest significant (p≤ 0.001) latency was 27.31±0.79 seconds displayed by the ethanolic extract A. flagellaris leaves with latency being reduced to time close to that of the control normal saline when rats pretreated with naloxone. When the sedative effect examined by the open-field method ; ethanolic extracts of T. uniflora roots (400mg/kg) had significantly (p≤ 0.001) decreased the squares crossed to 2.80±0.20 square at 120 minutes.

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