Effects of cadmium on phytochemical properties of licorice (Glycyrrhiza glabra L.)

The increasing popularity and trade of medicinal plants on the one hand, and the expansion of polluting water, soil and air resources on the other hand, have made the health, safety and quality of medicinal plants raw materials and their processed products a major concern of world organizations. Become more and more diverse and implement various research projects in this field. The present study aimed to investigate the effect of cadmium heavy metal on the phytochemical properties of licorice in a completely randomized design with cadmium treatment at 6 concentrations (0, 10, 20, 40, 80 and 160 (ppm)) and 4 replications. Potted cultivation (24 pots in total) was performed. After planting substrate and spraying cadmium heavy metal nitrate with above mentioned concentrations, licorice rhizomes were cultured in pots and kept in greenhouse for 7 months. Finally, dried and powdered plant samples (in two sections of aerial parts) were transferred to laboratory for measurement of phytochemical properties. The measured variables in the underground organs were glycyrrhizic acid, glabridine, liquoritin and in the aerial parts of routine and catechin flavonoids. Extraction was performed by ultrasonic and solvent methods. The best solvent for extraction of active substances in aerial and ground organs was determined after ethanol: water (70:30) tests and the measurements were performed by high performance liquid chromatography (HPLC). Comparison of mean cadmium concentrations in the studied concentrations showed that increasing the concentration of this element in soil had a significant effect on glycerolic acid, glabridine and liquoritin levels in groundwater and routine flavonoids and catechins in aerial parts of licorice. In this regard, glyceric acid and liquoritin were the most additive effects at concentration of 10 (ppm), 70.12 and 56.44%, and glabridine at concentration of 20 (ppm) at 51.70%, respectively. It also showed that the amount of active substances in licorice underground increased initially with cadmium treatment and then decreased with increasing concentration of heavy metal.