Taxonomic and Anatomical Characterization of Flowering Medicinal Plants Restricted to Riverbank Habitats

Abstract

Mentha is among the most important flowering medicinal plants; they are also a perennial, aromatic plant. The Mentha genus belongs to the Lamiaceae family. The Mentha genus comprises approximately 30 species, 14 hybrids, and numerous varieties. Mentha species are characterized by high essential oil concentrations, which are widely used in the pharmaceutical industry. Mint species are of medicinal and nutritional relevance, but studies dealing with their identification and categorization are few, especially in Iraq. Therefore, the present study was carried out to identify and categorize the flowering medicinal Mentha species growing along the riverbanks in Iraq, using morphological, anatomical, and biochemical analysis. The three Mentha species studied were Mentha spicata, Mentha piperita, and Mentha longifolia. Morphological and anatomical studies were carried out on leaves, flowers, and stems of M. spicata, M. piperita, and M. longifolia, and the results revealed obvious changes in most features between the species. The results also revealed that M. spicata and M. piperita were highly comparable for some morphological leaf characters, but M. piperita and M. longifolia were highly similar for some anatomical leaf characters. The biochemical study results showed that M. piperita had the greatest levels of DPPH radical scavenging activity (60.17%), total phenolic content (TPC: 46.11 mg/g), total flavonoid content (TFC: 28.12 mg/g), and essential oil content (EOs: 0.57%), followed by M. spicata and M. longifolia. The study revealed that morphological, anatomical, and biochemical analyses are effective and complementary ways to identify and classify species of the same genus. Although these methods have been successful in identifying and classifying the three mint species, there is a need to extend the study to a larger number of species and ensure their correct identification. Therefore, this study suggests future research for better identification and characterization of a broader range of Mentha species by adding additional methodologies, e.g., molecular characterization.