Free radical scavenging & Iron chelating capacity of Psidium guajavaand Persea americana leaf extract: A comparative study

Background: Oxidative stress is caused due to the discrepancy between reactive oxygen and nitrogen species with antioxidant system in the body. Free radicals which are produced endogenously destroy lipids, proteins and DNA biomolecules which results in cancer, ageing, autoimmune, cardiovascular and neurodegenerative disorders. Phytochemical constituents of plants such as Phenolic compounds, Flavonoids, Saponins and alkaloids act on free radicals which reduce oxidative stress induced complications. Present study was designed to compare the Free radical scavenging and iron chelating capacity of Psidium guajava and Persea americana leaf extracts. Methods: Ability to scavenge Hydroxyl radicals which was produced by Fenton reaction as described by Naskar et al26, using qurecetin as a standard. Iron chelating capacity of plant extract was determined by modified method described by Dinis et al25, using Disodium EDTA as standard. Results: At 10 μg concentration Psidium guajava and Persea americana displayed 77.92 ± 1.8 & 65.99 ± 4.17 % hydroxyl radical scavenging activity respectively, as compared to standard Qurecetin which displayed 89.84 ± 0.89 % scavenging activity. A dose dependent increase in scavenging activity was observed in the crude extracts. Chelating activity of plant extract was also observed to be increased in a dose dependent manner. At 10 μg concentration Psidium guajava and Persea americana displayed 57.49 ± 0.9 & 54 ±2.3% iron chelating activity respectively, as compared to standard Disodium EDTA that displayed 75.44 ± 0.33 % iron chelating activity. Conclusion: The results obtained from present in vitro study indicates that Psidium guajava and Persea americana are potential source of natural antioxidants. Psidium guajava leaf extract exhibited better in vitro antioxidant activity when compared to Persea americana.