Study of morphological diversity, total phenolic contents and antioxidant activity in different populations of Nepeta nuda and Nepeta crassifolia in habitats of Ardabil and East Azerbaijan provinces

Nepeta L., belongs to Lamiaceae family, is containing different annual and perennial species which are found in different parts of Asia, Europe and North Africa. In order to evaluate the morphological diversity, total phenolic content and antioxidant activity between 6 populations of Nepeta nuda and Nepeta crassifolia, the aerial parts of these plants in flowering stages were collected in summer 2015 from Ardabil and east Azerbaijan provinces. The morphological traits included plant height, number of sub-branches, leaf length and width, number of nodes, inflorescence length, internode length and length of sub-branch were measured. Methanolic extract were obtained by maceration, phenolic content by Folin-Ciocalto method and antioxidant activity were measurement DPPH radical scavenging capacity method, respectively. The experiment was performed in a completely randomized design with 3 replications and the comparison of data average was done by LSD test at 5% probability level. Results were showed that the first population (Nepetacrassifolia - Razi) was superior in morphological characteristics compared to other populations of this species. The highest antioxidant activity (74.96%)and total phenolic content (9.88mg of gallic acid equivalents per gram of fresh weight), was obtained from the leaves and flowers of population 3 (Heyran), respectively. Maximum plant height, leaf length and width, number of nodes were observed in population 6 (Meshkin) of Nepeta nuda and also the highest antioxidant activity and total phenolic content were perceived in leaves of population 5 (Heris) and flowers of population 4 (Meshkin-Heris), respectively. Generally the most total phenolic content and antioxidant activity between two species were observed in population 3 (Heyran) which is belong to the Nepeta crassifolia. It seems that the height of sea level had significant effect on populations phenolic content and antioxidant activity. So the populations of 1 and 6, which both species were desirable at evaluated morphological traits so that these populations can be considered in breeding and domestication programs.