Phytochemical Screening, Total Phenolic Contents and Biological Evaluation of Aerial Parts of Nepeta praetervisa

Summary: This study was designed to explore the phytochemical screening, total phenolic contents, radical scavenging potential and urease inhibitory activities in various fractions of the aerial parts of Nepeta praetervisa. Sub-fractions (n-hexane, chloroform, ethyl acetate, n-butanol, and aqueous) were prepared from the crude methanolic extract using partition chromatography. Phytochemical tests were performed and revealed the presence of various classes of secondary metabolites in various sub-fractions (Table-1). Total phenolic contents of all the fractions were determined using Folin-Ciocalteu (FC) reagent and the ethyl acetate sub-fraction was found to possess the highest level of phenolic contents (627.25 mg gallic acid equivalent (GAE)/g) as compared to the other fractions. The radical scavenging activity was determined at various concentrations ranging from 2.5 - 0.15µg /10µL by 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) method. At the lowest concentration level, the ethyl acetate sub-fraction showed maximum level of antioxidant activity (78%) compared to BHA used as standard. The decreasing order of activity was ethyl acetate>chloroform>aqueous>n-butanol>methanol>n-hexane. On the other hand when all these fractions were screened for urease inhibition activity using indophenols method, the ethyl acetate sub-fraction showed significant urease inhibitory activity (68 %) compared with the standard thiourea at the concentration of 50 µg /10 µL. The decreasing order of activity of various subfractions was ethyl acetate>chloroform>hexane>aqueous, while n-butanol sub- fraction was inactive.