Liquiritin Research Articles

Effects of space flight on DNA mutation and secondary metabolites of licorice (Glycyrrhiza uralensis Fisch.).

Licorice (Glycyrrhiza uralensis Fisch.) seeds were flown on a recoverable satellite for 18 days(the average radiation dose in the flight recovery module was 0.102 mGy/d, the distance from flight apogee to earth was 350 km, gravity 10−6). After returning to earth, the seeds were germinated and grown to maturity. The parallel ground-based seeds were also planted under the same conditions. The leaves of licorice were used for inter-simple sequence repeat (ISSR) analysis and the two main secondary metabolites in one-year-old roots were analyzed by high performance liquid chromatography (HPLC). Among 22 random primers used in this experiment, 6 primers generated different DNA band types. Analysis of HPLC showed that the content of glycyrrhizic acid (GA) and liquiritin (LQ) in the roots from seeds flown in space was respectively 2.19, 1.18 times higher than that of the control group. The results demonstrated that the extraterrestrial environment induced mutagenic effects on licorice and affected its secondary metabolites. These changes indicated that extraterrestrial orbit is possible means of breeding of licorice so as to preserve this endangered medicinal plant.

Liquiritigenin, a licorice flavonoid, helps mice resist disseminated candidiasis due to Candida albicans by Th1 immune response, whereas liquiritin, its glycoside form, does not

Licorice (the root of Glycyrrhizae plant) has been used as an oriental herbal medicine for thousands of years. The licorice flavonoid components are reported to possess immunomodulatory activities. In this present study, we investigated the immunomodulatory effects of liquiritigenin (LG) and liquiritin (LQ), licorice flavonoid components, against disseminated candidiasis due to Candida albicans, a dimorphic fungus, that causes severe disease via hematogenous dissemination and local diseases such as vaginitis and thrush. Results showed that direct interaction of LG or LQ with C. albicans yeast cells resulted in no growth-inhibition, in vitro. When tested in a murine model of disseminated candidiasis, mice given LQ intraperitoneally before intravenous challenge with live C. albicans yeast cells had similar mean survival times (MST) as untreated mice groups. On the contrary, mice given LG in the same manner as LQ above had longer MST than the untreated mice groups ( P < 0.05). In one experiment, 3 out of 5 LG-treated mice survived during the entire period of the 55-day observation. Furthermore, the 3 survivors were cured—shown by a lack of CFU (colony forming unit) in the kidneys. This protection was nulled when mice were pretreated with anti-CD4+ antibody before LG-treatment and challenge with the yeast. However, the protection was transferable by the CD4+ T cells isolated from LG-treated mice not infected with the yeast. In addition, mice given CD4+ T cells that were pre-treated with LG, in vitro were also protected against disseminated candidiasis. ELISA analysis revealed that in LG-treated mice IFNγ and IL-2 were dominantly produced compared to IL-4 and IL-10. When LG-given mice were treated with anti-mouse IFNγ, the protection was again nulled. Combined together, these results indicate that LG protects mice against disseminated candidiasis by the CD4+ Th1 immune response.

Extraction of nutraceutical compounds from licorice roots with subcritical water

Subcritical water (SBW) extraction of licorice root (LR) was carried out at four different temperatures (50, 100, 200, and 300 °C) for 10, 30, or 60 min, and nutraceutical compound levels of the SBW extracts were evaluated. SBW treatment of LR increased the antioxidant activity of extracts. Higher radical scavenging activity, reducing power, and total phenol content of the LR extracts were found when SBW extraction was carried at 200 °C for 60 min or at 300 °C for more than 30 min. The main active compounds such as glycyrrhetic acid (GA) and glycyrrhizin (GL) showed different extraction patterns. GA and GL were present at maximum levels following SBW extraction at 100 °C for 30 and 60 min, respectively. However, liquiritin (LQ), another nutraceutical compound of LR, showed the highest levels following extraction at 300 °C for 60 min. The results indicated that the temperature and time of SBW extraction significantly affected the antioxidant activities and nutraceutical compound levels of LR extracts.

Microwave-assisted Micellar Extraction and Determination of Glycyrrhizic Acid and Liquiritin in Licorice Root by HPLC

Abstract The feasibility of employing non-ionic surfactant (Triton X-100) as an alternative and effective solvent for the microwave-assisted extraction of glycyrrhizic acid (GA) and liquiritin (LQ) from licorice root was studied. The optimal extraction parameters based on the microwave-assisted micellar extraction technique were determined. Under the optimal conditions, i.e. 5% (by volume) Triton X-100, microwave-assisted extraction for 3—5min at 373K, the percentage extraction of active ingredients reached the highest value. The preconcentration factor for GA and LQ (about 13.5) and the extraction efficiency for these two ingredients approached 100% showed the coupling of microwave-assisted extraction and cloud-point extraction could be employed as a new and effective technique for the rapid extraction and preconcentration of pharmacologically active ingredients from medicinal plants such as licorice root without disturbing chromatographic analysis.

Separation of glycyrrhizic acid and liquiritin from licorice root by aqueous nonionic surfactant mediated extraction

Aqueous two-phase extraction with nonionic surfactant is a new class of extraction system due to their many unique properties such as safe and environmental friendly chemicals. In this study, investigation has been carried out to determine the suitability of a nonionic surfactant micellar extraction in replacing volatile organic solvents for extraction and separation of glycyrrhizic acid from aqueous licorice extraction solutions. New experimental data for the partitioning of two ingredients, glycyrrhizic acid (GA) and liquiritin (LQ), between water and micellar coacervate phase, at different pH values have been reported. The results confirm the suitability of this micellar extraction system for the purification of GA. GA from leaching solution of licorice root was quantitatively recovered in the coacervate phase, with the recovery of 95%, and it was subsequently separated from the surfactant by twice could point extraction with the recovery of 90.3%. The results also show that the partitioning of GA between coacervate and water phase is highly influenced by the pH of the solution as well as their chemical structures.

Separation of glycyrrhizic acid and liquiritin from Glycyrrhiza uralensis Fisch extract by three-liquid-phase extraction systems

Some stable three-liquid-phase extraction systems have been used for isolation and separation of glycyrrhizic acid (GA) and liquiritin (LQ) in aqueous Glycyrrhizia uralensis Fisch extract. Partition behaviors of two compounds were investigated at various conditions. Organic extractants and the pH of solution were two main factors to affect their partitioning among the phases and separation strategies. Different extraction profiles showed that the stronger the electron-donating capability of extractants, the higher the upper-limit of pH in the region for co-extracting GA and LQ, and the higher the lower-limit of pH in the region for stripping GA or LQ from the organic phase. Of all the investigated systems, the three-liquid-phase system containing poly(ethylene glycol-ran-propylene glycol) (EOPO2500) and tri-butyl phosphate (TBP) was the most suitable for separation and purification of licorice extract. FTIR and fluorescence spectroscopic investigations showed that hydrogen bond interaction and hydrophobic interaction among the phases were the main driving forces to affect the partition behaviors of two compounds.

Analysis and comparison of Radix Glycyrrhizae (licorice) from Europe and China by capillary-zone electrophoresis (CZE)

A simple capillary-zone electrophoresis (CZE) method for the analysis of plant specimens, Glycyrrhiza glabra L., G. uralensis Fisch. and G. inflata B at. (Leguminosae) as well as commercial licorices from Europe and China was developed. Contents of glycyrrhizin (GL), glycyrrhetic acid (GA), glabridin (GLAB), liquiritin (LQ) and licochalcone A (LC A) in ethanolic extracts were investigated. Optimum separation was achieved with sodium tetraborate buffer (pH 9.22; 70 mM); voltage, 25 kV. Recovery rate for GL was found to be 101.90 ± 2.54%. Adequate correlation was observed between GL contents measured by CZE and HPLC ( r = 0.977). Advantages over conventional HPLC analysis of Glycyrrhiza species are short analysis time (<15 min), simple running buffer preparation and the none-use of organic solvents. Using the present CZE method, it was demonstrated that (1) G. glabra was distinguished from G. uralensis especially by phenolic compounds GLAB ( G. glabra: 0.19 ± 0.11%; n = 53) and LQ ( G. uralensis, 1.34 ± 0.34%, n = 10); (2) on average, GL contents were higher in Chinese commercial licorices; (3) relatively high LC A contents were especially detected in a Chinese commercial licorice (origin estimated as G. inflata); (4) Glycyrrhiza species were also distinguished by applying PCA on the basis of CZE peak area data of GL, GLAB, GA, LQ and LC A; and (5) liquiritin apioside was found in all samples.

Permeability of the flavonoids liquiritigenin and its glycosides in licorice roots and davidigenin, a hydrogenated metabolite of liquiritigenin, using human intestinal cell line Caco-2

The present investigation focused on the transepithelial flux of liquiritigenin (LG), davidigenin (DG), liquiritin (LQ), and liquiritin apioside (LA) using the human colonic cell line Caco-2 as a model of human intestinal absorption. Apparent permeability coefficients ( P app) for the apical to basolateral flux of LG and DG were (16.0±0.727)×10 −6 cm/s and (18.2±1.67)×10 −6 cm/s, respectively. These P app were higher than that of the transcellular transport marker propranolol (13.5±0.34)×10 −6 cm/s ( P<0.01). P app for the apical to basolateral flux of LQ and LA were (0.26±0.12)×10 −6 cm/s and (0.075±0.005)×10 −6 cm/s, respectively. These P app were lower than that of the paracellular transport marker mannitol (0.64±0.04)×10 −6 cm/s (LG, P<0.01; LA, P<0.001). These data suggested excellent absorption of LG and DG through the human intestinal epithelial cell line. On the contrary, poor absorption of LQ and LA was expected due to the little transepithelial flux of these compounds in the human colonic cell line Caco-2.