Phytochemical Analysis and Biological Investigation of Nepeta juncea Benth. Different Extracts

This study was carried out to screen the amount and the classes of secondary metabolites and to evaluate the antioxidant, cytotoxic, antifungal, and antibacterial activities of the methanolic, ethanolic, and water extracts of the roots, leaves, and flowers of Nepeta juncea Benth. The results show that the highest total phenol (69.54 &plusmn
0.31 mg gallic acid equivalents (GAE)/g dry weight), total flavonoid (41.37 &plusmn
0.17 mg quercetin equivalents (QE)/g dry weight), anthocyanin (6.52 &plusmn
0.21 mg cyanidin/100 g dry weight), and tannin (47.36 &plusmn
0.33 mg catechin/g dry weight) concentrations were recorded in the methanolic extract of the leaves of N. juncea. The gas chromatography&ndash
mass spectrometry (GC&ndash
MS) analysis of the extracts showed that 1,8-cineole, 4a&alpha
7&alpha
7a&alpha
nepetalactone, &beta
pinene, terpinen-4-ol, and &alpha
terpineol were the major compounds, respectively. The best 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and ferric-reducing antioxidant, cytotoxic, antifungal, and antibacterial activities were observed for the methanolic extract of the leaves. For the two latter activities, the best activity was revealed on Staphylococcus aureus, Bacillus cereus, and Candida albicans. The minimum inhibitory concentration (MIC) values for the antimicrobial of the methanolic extract from the leaves were in the range of 25&ndash
100 &micro
g/mL, whereas the minimum bactericidal concentration (MBC) values were in the range of 50&ndash
200 &micro
g/mL. The results reported herein show that, for the first time in the literature, N. juncea is a remarkable source of antioxidant, antifungal, and antibacterial compounds.