Phytochemical profile and biological activity of a therapeutic orchid from Anatolia: Dactylorhiza romana subsp. georgica

Abstract

In Anatolia, the tubers of Dactylorhiza romana subsp. georgica orchid are consumed as food and frequently used in folk medicine to alleviate the symptoms of some disorders. However, these properties have not been scientifically studied until the present day. In this research, we aimed to identify phenolic profile of the orchid tubers and determine their several features and functions. Among these, there are the antioxidant and antimicrobial effects and the inhibitory effect against diabetes related enzymes (α-amylase and α-glucosidase). In this sense, total phenolic content (Folin–Cicalteu assay), total antioxidant capacity (Phosphomolybdate method), antioxidant (ABTS and DPPH assays) and enzyme inhibition effects of tuber extracts obtained with different solvents (chloroform, ethyl acetate, methanol, ethanol, or hexane) were determined by using spectrophotometric methods, and the phenolic profile was also analysed by HPLC. In addition, antimicrobial activity of the extracts against 3 g (+) and 3 g (−) bacteria and 2 forms of yeasts was determined by disc diffusion and micro dilution methods. Based on our findings, the total phenolic content and antioxidant properties of ethyl acetate extract were considerably higher than the others. The most abundant among the screened phenolic standards was found to be benzoic acid. The highest α-amylase and α-glucosidase enzyme inhibition was measured in methanol and chloroform extracts, respectively. The highest antibacterial (B. cereus) and anticandidal (C. tropicalis and C. albicans) activities were detected in the chloroform and ethyl acetate extracts, respectively. In short, it was clearly seen that the D. romana subsp. georgica tuber had a great potential for being used in food and drug industries as a source of bioactive compounds.