ABSTRACT
Oxidative stress is the root cause of many diseases, affecting the humans by deranging the balance between the oxidants and antioxidants. Pathologies, such as Alzheimer’s, Parkinson’s, diabetes and cancer have been well associated with the production of free radicals during various metabolic processes. Many medicinal plants are used to treat such kind of diseases since ancient times. Here, we evaluated the medicinal herb Rheum spiciformis Royle (RS), used commonly in folklore to treat many aliments for its potential against oxidative stress. Five different extracts (aqueous, chloroform, ethyl acetate, methanol and PET ether) of RS were evaluated against oxidative stress generated in vitro. Phytochemical constituents were assessed followed by total phenolics, DPPH, reducing power, hydroxyl radical scavenging activity and in vitro calf thymus DNA damage. The highest phenolic content (TPC) of 1191.65 mg GAE/g was observed in RS-MeOH extract. DPPH radical scavenging activity was found to be highest in RS-MeOH (96.60%) with IC50 125.91 µg/mL. The reducing power of the extracts increased in a concentration dependent manner. Again superoxide radical scavenging activity of RS extracts with IC50 values 34.10 µg/mL (RS-MeOH) for methanol was highest. The H2O2 scavenging activity 84.76 µg/mL shown by RS-MeOH extract at 250 µg/mL of plant extracts was the maximum. RS-MeOH showed great effect to scavenge free radicals as such prevents Calf thymus DNA damage induced by Fenton reaction. These results clearly indicate that RS-MeOH and RS-EtA among the five extracts possesses the highest positive modulatory effect on free radical scavenging on wide variety of free radicals as such can be employed as potential antioxidant and anti-inflammatory agent against various oxidative stress related pathological conditions.