10.22376/ijpbs.2019.10.1.p1-12 Volume 10 Issue 4 2019 (October-December) The present study was aimed to analyze the antioxidant and antimicrobial activity of essential oil (EO) from the rhizome of lessThan i greaterThan Cyperus corymbosus lessThan /i greaterThan Rottb. Further biological activity was correlated with its chemical constituents. The total phenol content present in EO was determined as 5.87 mg GAE/g EO. The EO recorded maximum inhibition of DPPH radicals (26.0 %) at 10% concentration with IC lessThan sub greaterThan 50 lessThan /sub greaterThan value of 21.46 %. Similarly, ABTS radical scavenging capacity of EO was found to be 30.7% at 10% concentration, and IC lessThan sub greaterThan 50 lessThan /sub greaterThan value was 16.04 %. The disc diffusion assay performed to analyze the antimicrobial activity of EO. Among the three ( lessThan i greaterThan Escherichia coli, Staphylococcus aureus lessThan /i greaterThan and lessThan i greaterThan Salmonella abony lessThan /i greaterThan ) bacterial species tested, lessThan i greaterThan Staphylococcus aureus lessThan /i greaterThan was found to be highly susceptible to EO, which recorded the highest of 2.3 mm zone of inhibition at 10% concentration of EO. Similarly, lessThan i greaterThan A. briselinesis lessThan /i greaterThan was found more susceptible, which recorded a 2.75 mm zone of inhibition at 10% concentration of EO. lessThan i greaterThan E. coli lessThan /i greaterThan was found resistant to EO, which recorded least of 0.5 mm zone of inhibition against highest concentration tested. The GC/MS studies of EO of lessThan i greaterThan C. corymbosus lessThan /i greaterThan rhizome indicates, presence of 42 different chemical compounds like Vulgarone-B - (27.04%), Nootkatone - (17.47%), Caryophyllene oxide - (15.07%), etc. This work revealed the potential of lessThan i greaterThan C. corymbosus lessThan /i greaterThan as a source of phyto-molecules for medicinal and pharmaceutical applications.  A. N. SANTHOSHKANNADA, M. K. MAHESH AND P. HARIPRASAD Cyperus corymbosus, Rhizome, DPPH, ABTS, Vulgarone-B 22-35