Micromorphological Characterizations and Phytochemical Contents of Some Phlomis Species from Iran

Objective: Microscopic characterization of a plant is a valuable method for accurate identification of the plant powder. The plants of Phlomis genus (Lamiaceae) are mostly distributed in the north and west of Iran with about 10 endemic species. In the present investigation, microscopic characterization of some Phlomis species including Phlomis bruguieri, Phlomis rigida, Phlomis kurdica, and Phlomis olivieri were assessed along with their phytochemical contents. Methods: The powders of the mentioned plants were analyzed using Zeiss microscope attached to a digital camera. Phytochemical contents of the plants extracts including total phenol, tannin, and polysaccharide were measured as well as a radical scavenging activity using the 2,2-diphenyl-1picryl-hydrazyl method. Results: The results of this study indicated that diacytic stomata, glandular trichome, stellate trichome, and crystals were the characteristic features of the examined species. Total phenol, tannins, and polysaccharides of the plants were assessed ranging 66.0-101.8 μg gallic acid equivalent in mg dry extract (μg GAE/mg EXT), 6.9-9.5 μg tannic acid equivalent in mg dry extract (TAE/mg EXT), and 512-559 μg glucose equivalent in mg dry extract (GE/mg EXT), respectively. Moreover, half maximal inhibitory concentration (IC50) values of radical scavenging activity of the extracts were calculated according to the plot of inhibition percentage against different concentrations of each extract as 218.6, 112.0, 113.3, and 58.7 μg/ml, respectively. Conclusion: The observed differences between Phlomis species can be applied in the accurate identification of these medicinal plants particularly in dried powdered materials regarding their microscopic characterizations and phytochemical contents.