LC-ESI-MS/MS analysis of total oligomeric flavonoid fraction of Cyperus rotundus and its antioxidant, macromolecule damage protective and antihemolytic effects.

In the present investigation, we identified the phytochemical constituents of total oligomeric flavonoid fraction (TOF) of Cyperus rotundus by LC-ESI-MS/MS and also demonstrated its antihemolytic effects against 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH) induced hemolysis of rat erythrocytes. Our results of TOF extract exhibited DPPH, metal chelating, ABTS, NO and hydroxyl radical scavenging activities with an IC50 values of 23.72±1.6, 52.45±2.88, 9.8±0.42, 6.5±0.33 and 120±6.83μg/ml respectively, whereas total antioxidant and reducing power activities were 194±12.5μg GAE/mg extract and 145±8.3μg AAE/mg extract. The extract showed potent inhibitory activity against AAPH induced plasmid DNA damage, protein oxidation and lipid peroxidation. The TOF extract mitigates AAPH induced hemolysis and exhibits ∼50% antihemolytic activity. TOF pretreatment also preserved morphology of erythrocytes as observed and measured by light microscope and atomic force microscope analysis. Furthermore, the TOF fraction effectively inhibited AAPH induced LDH release, ROS generation and lipid peroxidation. Taken together, our data demonstrate the antihemolytic activity of C. rotundus against AAPH induced oxidative stress of erythrocytes, and was associated with the decrease in oxidative stress, cellular damage and protection of macromolecules. In conclusion, the effects might be correlated with high content of flavonoids and polyphenols identified in C. rotundus. This suggests the clinical application of TOF fraction of C. rotundus against ROS induced cell death.