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

Abstract

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 sub-fractions was ethyl acetate>chloroform>hexane>aqueous, while n-butanol sub- fraction was inactive.