Comparison of Phytochemical Composition and Antioxidant Activity of Seven Nepeta species Cultivated in Mashhad

In the present research, phytochemical composition and antioxidant activity of seven Nepeta species (Nepeta teucriifolia subsp. teucriifolia, N. assurgens, N. glomerulosa, N. cataria, N. binaloudensis, Na. racemosa var. crassifolia) from field cultivated plant (Research garden of Agricultural Faculty of Ferdowsi University of Mashhad) in a completely randomized design with 3 replications were investigated. Total iridoid, flavonoid content (FC), total phenol (TP) content and antioxidant capacities (AC), were determined using spectrophotometer. The essential oils, were analyzed by GC/MS. The TP content ranged from 186.47 to 464.25 mg of gallic acid equivalents (mg (GAE) 100 g-1 DW). The highest and the lowest amount of FC with values of 43.08 and 142.20 (mg quercetin equivalents 100 g-1 DW) for N. glomerulosa and N. teucriifolia subsp. teucriifolia respectively. The AC values of the species ranged from from 117 to 287.33 μg mg-1 DW extract (by DPPH method) and from 66.678 to 81.096 Mm Fe (by FRAP method) respectively. The highest and lowest amount of essential oil percent (v/w) was obtained in N. assurgens (0.74) and in N. fissa (0.06), respectively. Depending on the result of this research, on the basis of main compound identified in the essential oils, Nepeta species have been divided in to three groups. First group species like; N. teucriifolia subsp. teucriifolia and N. glomerulosa which contain Caryophyllene oxide and Humulene as their main compounds. The species of the second group contain Nepetalactone isomers and 1.8-cineole as their key compounds. These species including N. binaloudensis and N. assurgens species. The species of the last group contain Nepetalactone as their key compounds; this species including; N. cataria, N. kotschyi, N. racemosa var. crassifolia.