Importance of phenolics in populations of Teucrium chamaedrys (Lamiaceae) from serpentine soils

Abstract

The genus Teucrium includes perennial herbs or shrubs widespread all around the world. The wall germander (Teucrium chamaedrys L.) is widely used in traditional and modern medicine for various health disorders and recent research revealed that serpentine populations of this herb have increased antioxidant and respective medical potential compared with calcareous population. The present study aims to elucidate further the role of phenolic compounds for T. chamaedrys growth on serpentine soil. Methanol extracts from two serpentine and two non-serpentine (calcareous and siliceous) Bulgarian populations were obtained and analysed for total quantity of phenolics and flavonoids, and antioxidant activity. The serpentine soils acted as an elicitor of the antioxidant response in T. chamaedrys plants and the increased phenolics level correlated with enhanced antioxidant activity. The calcareous population had lower values but still higher than the siliceous population which had the lowest antioxidant values, although the flavonoid quantity that was equal to the serpentine populations. A gas chromatography-mass spectrometry (GC-MS) assay for identifying phenolic acids pointed to caffeic acid as a dominant compound, with additional cinnamic and benzoic acid derivatives with putative roles as antioxidants, in cell wall lignification for heavy metals chelation, and for interspecies interactions.