Document Type : Full Paper
Author
Department of Agriculture, Medicinal Plants and Drugs Research Institute, Shahid Beheshti University, Tehran, Iran
Abstract
Keywords
Main Subjects
Extended Abstract
Introduction
Licorice (Glycyrrhiza glabra L.), as a strategic and very valuable plant in Iran, is overused and is endangered. Although the government has adopted strict regulations to prevent the extinction of licorice, the destruction of its habitat, due to improper and indiscriminate exploitation is still a serious threat. Since the propagation and reproduction of many endangered medicinal species is prolonged and the speed of their habitat renewal is lower than the speed of their exploitation from nature, the issue of their protection becomes more important. Licorice is a perennial herbaceous plant with antioxidant, antimicrobial, antiviral, anti-inflammatory and anticoagulant properties Licorice is one of the most valuable economic plants in the world, which is widely used in cosmetics, tobacco, pharmaceutical and food industries, and Iran is one of the major exporters of licorice roots. Given the importance of licorice phytochemical compounds such as glycyrrhizic acid, glabridin, liquiritigenin, and liquiritin as well as the increasing demand for their utilization in industry, the present study aimed to introduce genotypes rich in phytochemical compounds from cultivated Iranian G. glabra populations. This study not only introduced superior genotypes in terms of phytochemicals, but also focused on comparing these medicinal compounds in cultivated populations. These introduced populations can be used in future breeding programs to release new bred licorice cultivars for commercial cultivation.
Matrial and methods
In this study, the variation in phytochemical traits among different Iranian licorice landraces cultivated in field conditions, was investigated. Rhizomes of different populations were collected from different regions of Iran in 2019 and were planted in a randomized complete block design with 5 replications in the medicinal plants collection of Shahid Beheshti University. The rhizomes of plant samples were harvested at the end of the season (autumn) of the third year of cultivation. Then, after washing, the samples were transferred to the laboratory and dried at 25 °C. In order to extract the samples, they were powdered by an industrial mill. The studied traits were glycyrrhizic acid, glabridin, liquiritigenin, liquiritin, rosmarinic acid, rutin, total phenol, flavonoids content and antioxidant activity. Glycyrrhizic acid, glabridin, liquiritigenin, liquiritin, rosmarinic acid and rutin content were measured by High Performance Liquid Chromatography (HPLC). The total phenol content, total flavonoid content and antioxidant activity were measured by the folin–Ciocalteu, aluminum chloride and DPPH methods, respectively.
Results and Discussion
According to the results, the highest content of glycyrrhizic acid (155.17 mg.g-1 dry weight) and glabridin (19.46 mg.g-1 dry weight) were observed in Kazerun and Ilam populations, respectively. The population of Yasuj had the greatest amount of liquiritin (5.32 mg.g-1 dry weight) and liquiritigenin (12.16 mg.g-1 dry weight). The maximum content of total phenol (8.36 mgGAE.g-1 dry weight) and total flavonoid (27.28 mgQUE.g-1 dry weight) was observed in Kashmer and Baft populations, respectively. Bradsir and Kazerun had the highest concentration of rutin (5.93 mg/g dry weight) and rosmarinic acid (0.624 mg.g-1 dry weight), respectively. The results also showed that the glycyrrhizic acid content had a positive and significant correlation with liquiritigenin content at 5 % probability level. A positive and significant correlation was observed between glabridin and liquiritin contents at 5% probability level, but it had a significant negative correlation with IC50. Based on the results of cluster analysis, 22 licorice populations were categorized into five main groups comprising ten, two, two, one and seven populations, respectively. Factor analysis showed that the first four factors explained 69.21% of the total variance. The first to fourth factors accounted for 24.26%, 17.10%, 15.49% and 12.34% of the total variance, respectively.
Conclusion
Knowledge of different phytochemical characteristics helps breeders in the improvement and domestication of plants. This was a practical research study to create the possibility of selection in order to select desirable populations of licorice. The results of this research showed that there are high levels of diversity among licorice populations in terms of phytochemical characteristics including glycyrrhizic acid, glabridin, liquiritigenin and liquiritin contents. In general, this study showed that different licorice populations have high phytochemical potential and diversity, so that Kazerun, Ilam, and Yasouj were superior populations in terms of glycyrrhizic acid, glabridin, liquiritigenin and liquiritin contents, respectively, and depending on the industry's needs, they can be used for breeding programs, domestication and introduction to the licorice cultivation system.
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