Objective: The aim of the study was to analyze phenolic compounds of three species of Ornithogalum viz Ornithogalum virens, Ornithogalum thyrsoides, Ornithogalum dubium and to assess their bioactivity in terms of antimicrobial and antioxidant potential.Methods: Extracts were prepared in 20% aqueous methanol. Each extract was subjected to phenolic and flavonoid estimation. Antioxidant activity was tested using DPPH method, and their antimicrobial activity was tested on six pathogenic strains namely Enterobacter cloacae, Serratia marcescens, Escherichia coli, Shigella dysenteriae, Staphylococcus aureus and Pseudomonas aeruginosa. The extracts were subjected to HPLC analysis with different standards namely gallic acid, caffeic acid, p-coumaric acid, syringic acid, sinapic acid, ferulic acid, methyl gallate, catechin, rutin, apigenin, quercetin, myricetin, and kaempherol.Results: O. dubium was found to have highest antioxidant activity (IC50 311 µg/g extract). Inhibition zone was minimum in S. marcescens and E. coli on the application of extracts of O. virens, and the consequent MIC was 670 µg and 650µg/g dry weight respectively. None of the three extracts was found to have any effect either on S. aureus or P. aeruginosa. HPLC analyses have shown that myricetin was the primary flavonoid constituent of the extract of O. dubium and gallic acid of O. virens.Conclusion: O. dubium shows maximum antioxidant and antimicrobial activity. Extracts of O. virens also shows maximum polyphenol content. From the HPLC results, it is evident that the flavonoids present in O. dubium are myricetin, rutin, p-coumaric acid along with some phenolic compounds, which confers bioactivity to the extract.Keywords: Ornithogalum, Phenolic acid, Flavonoids, HPLC, Antioxidant activity, Antimicrobial activit
