Biological activities, phenolic constituents and mineral element analysis of two endemic medicinal plants from Turkey: Nepeta italica subsp. cadmea and Teucrium sandrasicum

Abstract

Lamiaceae plants are widely used in traditional medicine as a cure for various disorders. Nepeta italica L. subsp. cadmea (Boiss.)A.L.Budantsev and Teucrium sandrasicum O.Schwarz are medicinal species belonging to the Lamiaceae family and are endemic to Turkey. The present study was designed to investigate the biological activities (antioxidant and toxicity)and phenolic content of these plants' extracts as well as to determine their mineral elements. The antioxidant properties of these plants were determined using the scavenging methods (DPPH and ABTS), total antioxidant test systems (ß-carotene/linoleic acid and phosphomolybdenum), metal chelating and reducing power assays. The phenolics were identified using HPLC and the brine shrimp lethality test was used to screen for possible toxicity. In addition, an evaluation was made of some mineral elements (P, Mg, K, Fe and Cu). The hydroethanolic extract of N. italica subsp. cadmea, showed the highest amount of antioxidant activity (ß-carotene, ~ 93%)among the extracts that were investigated. All the extracts exhibited chelating and reducing activities. There were statistical differences among the scavenging activities of the N.cadmea and T. sandrasicum extracts. The total antioxidant capacity of the extracts evaluated with the phosphomolybdenum test was in the range of 61.54–143.97 µg/mg and that these plants possess mineral elements. These types of investigations are important for gaining more information about the potential natural antioxidants from various Lamiaceae plants. The findings of the present study will provide additional information for understanding the efficacy of these medicinal plants as a food ingredient, as well as for use in medicinal applications. © 2019 South African Association of Botanists