Phytochemical Analysis of the Medicinal Plant Terrestrial Orchid (Orchis Simia) in the Flowering Stage

Extended Abstract Background: As one of the medicinal plants from the Orchidaceae family, Orchis simia tubers are traded all over the world. The unmarketable parts are usually discarded (e.g., inflorescence, leaves, and stems) and produce a large amount of unused biomass. Medicinal effects of plants usually result from the composition of their secondary metabolites. Identification and quantification of secondary metabolites will play an important role in exploiting the medicinal potential of the plant. Orchids grow in different environments and habitats, mainly due to the presence of a unique set of secondary metabolites that help these plants tolerate stressful conditions. Therefore, following traditional approaches, these plants have been proposed as an important source for biological exploration. A number of compounds obtained from different parts of the orchid indicate biological activity. Alkaloids, flavonoids, phenanthrenes, terpenoids, bibenzyl derivatives, and other biologically active compounds have been reported in orchids. The present study identifies the phytochemical substances in Orchis simia orchid. Methods: To investigate the phytochemistry of the inflorescence, leaf, and stem of Simia orchid separately, the samples were collected from nature, washed with water, and dried in the shade. Each of the organs was then powdered separately, and methanolic extract was extracted by ultrasonic and centrifugation methods. Total phenol was evaluated by the Folin-Ciocalteau method. Antioxidant capacity was determined by the FRAP method. The main compounds were estimated quantitatively and qualitatively by high-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS) methods. Results: HPLC and LC-MS analyses of O. simia samples led to the isolation of 28 secondary metabolites (four compounds of bibenzyl derivatives, eight phenolic and flavonoid compounds, and 16 alkaloid compounds). Phenolic and flavonoid compounds identified in Simia orchid included benzoic acid, caffeic acid, m-coumaric acid, rutin, luteolin, kaempferol, quercitrin, and quercetin. In parallel, the total phenol content and total antioxidant capacity of the extracts were also measured in the extract. The results of variance analysis of the obtained data showed that the leaf, stem, and inflorescence samples were significantly different from each other at the 1% level in terms of total phenol content and total antioxidant capacity. Among the studied organs, inflorescence extract was superior to the other studied tissues in terms of 28 secondary metabolites as well as total phenol and antioxidant capacity. The average comparison results showed that the total phenolic compounds and antioxidant capacity in different organs of the O.s simia plant were not the same, and they were placed in three different groups. The highest total phenol content (138.65 mg GAE/g dry weight) was observed in orchid inflorescences. The highest and lowest levels of antioxidant activity were obtained from inflorescence (77.58 μmol/g) and stem (53.24 μmol/g) samples, respectively. Conclusion: A proper knowledge of the chemical composition of a plant leads to a better understanding of its potential medicinal value. In this research, therefore, the changes in biochemical compounds and antioxidant capacity of the extracts were studied in leaf, stem, and inflorescence organs. According to the results of this research, the inflorescence of O. simia is a potential source of antioxidant capacity, phenol, and alkaloids, which will have an important medicinal role. The secondary metabolites obtained from this plant are reported for the first time and will be useful for new medicinal developments and applications in the future. Moreover, this study will help reduce the waste of this orchid in industrial production because its aerial organs can be exploited for medicinal purposes.