Journal of Mazandaran University of Medical Sciences (May 2024)
Evaluation of Antioxidant and Antihypoxic Activities of Convolvulus Fruticosus in Mice
Abstract
Background and purpose: The Convolvulus genus (Convolvulaceae) is one of the medicinally and economically important genera, including about 250 species broadly distributed worldwide. Many researchers have paid attention to this genus because of its important phytochemical composition, biological activities, and safety. The Convolvulus genus contains various chemical profiles such as flavonoids, phenolic acids, coumarins, tannins, and essential oils. All the parts of these plants possess pharmacological activities such as antimicrobial, anticancer, and antioxidant activities. This investigation was designed to study the antioxidant and antihypoxic activities of C. fructicodus. Materials and methods: The aerial parts were extracted by maceration with methanol as a solvent. In this experimental study, antioxidant activities were evaluated by four methods, DPPH and nitric oxide radical scavenging activities, iron chelatory capacity, and reducing power. Total phenolic and flavonoid contents were also investigated. High-performance liquid chromatography was used for the determination of phenolic compounds. The protective effects of extract at 62.5-250 mg/kg were evaluated against hypoxia-induced lethality in mice by three experimental models of hypoxia, i.e. asphyctic, haemic, and circulatory. The time it took for the mice to die (latency for death) was recorded in minutes. The Institutional Animal Ethical Committee of Mazandaran University of Medical Sciences approved the experimental protocol. In the asphyctic hypoxic model, phenytoin (50 mg/kg, i.p.) and in the next two tests, propranolol (20 mg/kg, i.p.) were used as the positive control. Normal saline (0.5 ml, i.p.) was used as the negative control. Analysis of variance was performed followed by Newman-Keuls multiple comparisons (by GraphPad Prism 8) to determine the differences in means. The extract did not show any metal-chelating activity in the chelating test. Results: Total phenolic and flavonoid contents of the extract were 113.37 GAE and 20.32 QE, respectively. IC50 of extract for DPPH radical-scavenging activity and nitric oxide-scavenging were 85.28 and 177.40 µg/ml, respectively. The extract showed a good effect in reducing the power test and there was no significant difference between extract and standard in higher concentrations (p>0.05). In the haemic model, the extract showed a good and dose-dependent effect in all tested doses. The extract at 62.5 mg/kg increased the survival time by about 2 minutes (P<0.01). At 250 mg/kg, the extract showed a similar effect to propranolol. In the circulatory model, it showed very good completely dose-dependent effects. At 62.5 mg/kg, the extract increased the survival time by more than 2 minutes (P<0.01). The extract at 250 mg/kg increased the survival time by about 8 minutes (P<0.0001). The effect of the extract at 62.5 mg/kg was similar to propranolol. In the asphyctic model, the extract did not show activity in any of the tested doses. Conclusion: The presence of phenolic compounds in the extract can be responsible for the antioxidant activity observed in the plant extract. By conducting anti-hypoxia tests in two models of haemic and circulatory models, the extract was able to show good protective effects in increasing the survival time of mice. The good antioxidant activity of this extract can be a possible mechanism for the anti-hypoxia activity.
