دراسة تصنيفية لأنواع مختارة من الجنس Centaurium من العائلة Gentianaceae وإختبار فعاليتها التثبيطية ضد نوعين من الفطريات الممرضة في العراق

A Taxonomic Study of Selected Species of the Genus Centaurium from the Family Gentianaceae and Testing Their Inhibitory Effectiveness Against Two Species of Pathogenic Fungi in Iraq

The current research dealt with a taxonomic study of the species:
Centaurium pulchellum (Sw.)Druce, Centaurium spicatum (L.) Fritsch and Centaurium tenuiflorum (Hoffmanns. & Link) Fritsch. From the Gentianacea family, it focused a studying of the vegetative and reproductive parts from several aspects, such as morphology, anatomy, indumentum, a scanning electron microscope study, and chemically active materials, in addition to that, a study of the inhibitory effectiveness of the species’ extracts against some pathogenic fungi and yeasts.
The study was conducted in the laboratories of Biology Department / College of Education for Pure Sciences / University of Karbala, in cooperation with the Electron Microscope Imaging Unit / College of Engineering / Amirkabir University in Tehran and the laboratories of Al-Zahra University of Medical and Pharmaceutical Sciences for the period from November 2023 – June 2024.
The Morphological study included a study of the quantitative and qualitative characteristics of each of the leaves, flowers, fruits, seeds, and pollen grains, and it yielded a number of interesting characteristics that distinguished between the species, including the shape of the leaves and the shape of their apex , the color of the petals, their shapes, and the shapes of their apex, the shape of the sepals, the shape of the stigmas, the shape of the fruit and seeds, and dimensions. The vegetative parts, such as the height of the plant, the dimensions of the leaves, and the number of sepals, were larger in the species C. tenuiflorum, as well as the dimensions of the floral parts, such as the petals, sepals, stamens, and pistils, which were larger in the same type mentioned above, while the smallest dimensions were recorded for most of the external and floral parts in the species C. spicatum. As for the anatomical aspect, the characters of the upper and lower epidermis were measured and described for the leaves, bracts, floral parts, stem and root epidermis, as well as the transverse sections of the stem and root. It turned out that many of these characters are important in diagnosing the two species, as C. pulchellum and C. spicatum were distinguished by stomata with an Anomocytic type, while C. tenuiflorum had a Anisocytic stomatal type. The cuticles of all studied vegetative parts were characterized by their lack of surface covering, except for C. tenuiflorum. It is distinguished by the presence of papillae in the epidermis of the stems, and these characters are extremely important for the taxonomic isolation of species. Also, microscopic morphological study using the scanning electron microscope(SEM) revealed many characters, such as the type of surface decoration of the leaf epidermis, as the lower and upper epidermis ranged from smooth to reticulated, and were characterized by cells of irregular shape and devoid of indumentum, and the presence of two types of Anomocytic and Anisocytic of stomata that distinguished between the species, in addition to the pattern and nature of the wavy walls to highly wavy, as well as the characters of the surfaces of the stem epidermal cells, which was useful in taxonomically isolating the species due to the presence of papillae in the species C. tenuiflorum and shape of the stomata, which ranged from thin elliptical to elongated circular. The precise morphological characters of the surfaces of the floral parts were studied, such as the upper and lower surfaces of the petals, which were striped transversely and gave The importance in isolating species taxonomically is the pattern and nature of the walls and crests on the surfaces of the cells that protrude longitudinally, and the pattern of decoration on the surfaces of the crests. This is also the case for the characteristics of the surfaces of the anthers, the filaments , and the pistils with their parts, the ovary, the styles, the stigma, and the surfaces of the floral bracts and the floral calyx. All of these parts are characterized by the protrusion and convexity of their surfaces with a striped decoration, or transversely on the cells, as in the surfaces. The petals or longitudinally on the surfaces of the rest of the plant parts, and the precise phenotypic characteristics of the pollen grains were identified, such as the surface decoration, as the species under study were characterized by the irregularly striated to reticulated decoration. The characters of the shapes of the pollen grains in tropical and polar appearance gave importance in isolating the species taxonomically, as the species C.pulchellum was distinguished by its pollen grains. It has a rectangular shape with straight side walls, while the species C. spicatum and C. tenuiflorum have shapes that range from oval to elliptical with curved walls. This is also the case with the polar view. species C. pulchellum and C. spicatum are characterized by a spherical shape, but in the species C. tenuiflorum they are triangular in shape.The study also examined the chemical content of the ethanolic extract of the vegetative and floral parts of the species. The compounds were identified using Gas Chromatography Mass Spectrometry (GC-MS) technology. It was found that there were nine chemical compounds in the C. pulchellum species, three compounds in the C. spicatum species, and seven compounds in the species C.tenuiflorum, resulting from secondary metabolism, which has an effective role in medical treatments and as a means of defense for plants. It included many compounds belonging to phenols, organic silicon, alkaloids, terpenes, steroids, esters, unsaturated fats, and essential oils, and was characterized that the extracts of the two species C. pulchellum and C. tenuiflorum had an increase in the percentage of phenols represented by
paracetamol by more than 80-90%, while in the species C. spicatum the percentage of organic silicon compounds increased by 90%. The active compounds had an effective role in distinguishing between the species taxonomically, and the importance of those The compounds were tested for their effectiveness against some fungal pathogens (Aspergillus flavus and Candida albicans), which showed the lethal inhibitory activity of the species extracts at concentrations of 15% and 20% against fungi and yeasts. The variation in inhibitory activity gave distinction between the species.
The study concluded by confirming the current taxonomic status of the species Centaurium pulchellum (Sw.)Druce, Centaurium spicatum (L.) Fritsch and Centaurium tenuiflorum (Hoffmanns. & Link) Fritsch. It belongs to the Gentianaceae family.