Biological Activity and Characterization of Volatile Compounds ofTeucrium orientaleVar.glabrescensby SPME and GC-FID/MS

Abstract

This study describes the constituents of phenolic acids, volatile components, antioxidant and antimicrobial activities of Teucrium orientale var. glabrescens. Antioxidant activity of methanolic and aquous extracts were examined by three different methods, namely ferric reducing antioxidant power, cupric reducing antioxidant capacity and 2,2‐diphenylpicrylhydrazyl radical scavenging activity. The phenolic constituents were also determined by reverse phase‐high performance liquid chromatography. Solid phase microextraction of Teucrium orientale var. glabrescens was analyzed by Gas Chromatography‐Flame Ionization Dedector/Mass Spectromerty, Solid‐Phase Microextraction (GC‐FID/MS, SPME). The antimicrobial activity was studied by agar diffusion method. Extracts showed strong antioxidant and antimicrobial activity and contained large amounts of antioxidant compounds. Rosmarinic acid, p‐coumaric acid and p‐hydroxybenzoic acid were detected in methanolic extract of plant. Aquous extract was especially effective against Mycobacterium smegmatis. The main chemical classes identified consisted of aldehydes (32.5%), hydrocarbons (29.8%) and monoterpene hydrocarbons (29.8%). Common volatile components of plant detected included nonanal, thuja‐2,4 (10)‐diene and tetracosane. Practical Applications Medicinal plants are natural resources used in the treatment of various ailments. Teucrium species have been widely used in folk medicine as a remedy for gastritis, parasitic worms, colds, digestive ulcers, etc. Teucrium species are the subject of growing interest because of their biological properties. Although studies on screening the antimicrobial, and antioxidant activity of the Teucrium species have been done densely, studies on phenolic compounds of Teucrium orientale var. glabrescens are very limited. Teucrium orientale var. glabrescens extracts studied proved to be a good source of antioxidants, antimicrobial agents and volatile components that might serve to protect health and fight against several diseases.

Morphology and phytochemistry of Teucrium chamaedrys L. (Lamiaceae) cultivated at the Ghirardi Botanic Garden (Lombardy, Northern Italy)

“…Indeed, although the sesquiterpene hydrocarbons invariably constituted the dominant chemical family, a high level of variability emerged among the most abundant compounds. Only β-caryophyllene resulted common to our samples, T. marum, T. flavum and T. polium (Djabou et al, 2013a;Sagratini et al, 2012;Yildirmiş et al, 2017;Zouaoui et al, 2020). Concerning the other two main compounds of our samples, muurolene and cubebene occurred as alpha isomers in the Algerian species with relative abundances <2.0% (Zouaoui et al, 2020), while they were absent in the other literature profiles.…”

“…Phytochemical investigations on the volatile components referred to two studies on the characterization of the Volatile Organic Compounds (VOCs) spontaneously emitted by leaves of Turkish specimens using the Direct Thermal Desorption (DTD) technique (Karimi et al, 2011;Özel et al, 2006). In addition, the volatile profiles of congeneric species of different origins, including T. marum, T. orientale, T. polium, and T. flavum, were characterized by means of Headspace Solid-Phase Microextraction (HS-SPME) analysis (Djabou et al, 2013a;Sagratini et al, 2012;Yildirmiş et al, 2017;Zouaoui et al, 2020). Furthermore, the composition of the essential oils from aerial parts of T. chamaedrys of different origins was analysed (Bezić et al, 2011;Djabou et al, 2013b;Hajdari et al, 2020;Kaya et al, 2009;Sajjadi and Shookohinia, 2010).…”