With the technological development in biologically orientated industries more and more natural products in powdered form are being handled and processed. Three differently comminuted liquorice rhizome products were classified into 23 narrow size fractions to investigate the particle and bulk characteristics of the material, and to study the influence of particle shape on powder flowability. The morphology of the fibrous particulate was investigated by using a Quantimet 720 Image Analyser. The perimeter (P), projected area (A), breadth (B), length (L), horizontal and vertical projected lengths (P V and Pi) and the horizontal and vertical Feret diameters (FV FH) were measured from which four dimensionless shape factors were evaluated, [P2/47rA, PHxPV/A, L/B, FV/FH]. The surface texture of the particles was measured by fractal analysis. The influence of particle shape and size on the mean flow rate, coefficient of flow variation and flow uniformity were measured using a specially designed inclined tube flowmeter. The failure properties of powdered liquorice when sheared under known normal compressive stresses were measured and from a series of yield loci the unconfined yield strength, major consolidation stress and effective angle of internal friction were obtained. The effects of particle shape and size on the angle of internal friction, wall friction, bulk and packed densities were. investigated and the experimental correlations expressed in terms of mathematical equations. These relationships, together with the failure function plots, indicate that comminuted liquorice powder behaves as a "simple" powder.

With the technological development in biologically orientated industries more and more natural products in powdered form are being handled and processed. Three differently comminuted liquorice rhizome products were classified into 23 narrow size fractions to investigate the particle and bulk characteristics of the material, and to study the influence of particle shape on powder flowability. The morphology of the fibrous particulate was investigated by using a Quantimet 720 Image Analyser. The perimeter (P), projected area (A), breadth (B), length (L), horizontal and vertical projected lengths (P V and Pi) and the horizontal and vertical Feret diameters (FV FH) were measured from which four dimensionless shape factors were evaluated, [P2/47rA, PHxPV/A, L/B, FV/FH]. The surface texture of the particles was measured by fractal analysis. The influence of particle shape and size on the mean flow rate, coefficient of flow variation and flow uniformity were measured using a specially designed inclined tube flowmeter. The failure properties of powdered liquorice when sheared under known normal compressive stresses were measured and from a series of yield loci the unconfined yield strength, major consolidation stress and effective angle of internal friction were obtained. The effects of particle shape and size on the angle of internal friction, wall friction, bulk and packed densities were. investigated and the experimental correlations expressed in terms of mathematical equations. These relationships, together with the failure function plots, indicate that comminuted liquorice powder behaves as a "simple" powder. / Darou-Pakhsh Pharmaceutical Company

Introduction: Dark spots appearing on the skin caused by hyperpigmentation results from the action of tyrosinase, an enzyme whose activity leads to the production of the skin pigment melanin. Extracts of the plant Glycyrrhiza glabra, also known as liquorice, are commonly used to treat a range of conditions including skin hyperpigmentation. This study aimed at isolating and identifying compounds in extracts from South African liquorice root and assaying these compounds as to their antioxidant activity, their ability to inhibit the tyrosinase enzyme and their level of cytotoxicity. Methods: The ability of plant extracts to scavenge free radicals was tested using the 2,2-diphenyl-1-picrylhydrazyl (DPPH), [2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonicacid)] (ABTS) and the ferric ion reducing power (FRAP) tests. The polyphenolic content of extract fractions was determined and extract compounds were identified using UHPLC-QToF-20 MS. In vitro anti-tyrosinase activity was also investigated as well as cytotoxicity in HepG2 liver and SK-MEL-1 melanoma cells using the MTT cell viability assay. Results: Of the four fractions prepared from the 70% methanolic extract of liquorice root, fraction 3 (F3) showed increased polyphenolic content and antioxidant properties with IC50 of 56.1 ± 6.32, 39.14 ± 1.1 and 66.34 ± 1.4 μg/ml against DPPH, ABTS and FRAP, respectively. The anti-tyrosinase activity of this fraction showed an IC50 of 358.54 μg/ml compared to Kojic acid (0.75 mM) used as the control. In addition, this fraction showed reduced liver toxicity as a higher percentage cell viability was noted in the HepG2 cells compared to the SK-MEL-1 skin melanoma cells. However, both cell types showed higher percentage viability compared to acetaminophen that was used as cytotoxic control. The LC-MS analysis revealed the presence of a wide variety of compounds including 4-azido-3-benzyl-coumarin, ferulic acid, glycyrrhizin, quercitrin, cirsilineol, gentioflavine and 4'',6,7-trihydroxyisoflavone. The literature indicates the use of these compounds regarding antioxidant and anti-tyrosinase activity. Significantly, cularidine was identified in this study, a compound not previously reported in studies involving liquorice root. Conclusion: The results from this study concur with previous reports as to the anti-tyrosinase and antioxidant activities associated with liquorice roots, activities perhaps due to the relatively high polyphenolic content in extracts from South African liquorice root. / Life and Consumer Sciences / M. Sc. (Life Sciences)