Abstract

Free radical scavenging and antibacterial activity of essential oil and solvent extracts of Iris planifolia (Mill) was investigated. The essential oil was analyzed by Gas chromatography mass spectrometry (GC-MS) and a total of 38 types of volatile organics were identified. The essential oil consists chiefly of alkanes (36.5%), acids (19.1%), ketones (11.7%), alcohols (9.0%), arylpropanoids (6.8%) and aldehydes (4.1%) accompanied by relatively much smaller amounts of monoterpenes (1.0%). The antimicrobial activity of essential oil and ethanolic extract shows an important activity against Salmonella typhimurium and Klebsiella pneumoniae with minimum inhibitory concentration (MIC) of 3.12 mg/ml. Furthermore, the free radical scavenging assay of the essential oil and extracts were determined using a 2,2-diphenyl-1-picrylhydrazyl (DPPH) test system. The dichloromethane and water extract possessed strong radical scavenging activity with the lowest IC₅₀ value of 0.1 mg/ml followed by the aqueous extract with an IC₅₀ value of 0.12 mg/ml. Phytochemical analysis revealed the presence of flavonoids, terpenoids, saponins, alkalois and tannins which may be responsible for antimicrobial and antioxidant activities.

Key words: Iris planifolia (Mill), essential oil, GC, GC/MS, phytochemical prospecting, antimicrobial and free radical scavenging.