The Mealiness and Quality of Herbal Medicine: Licorice for Example

Background: The morphological identification is an effective and simple quality evaluation method in Chinese drugs, and the traits of mealiness and color were widely used in the commercial market of Chinese drugs. Objective: The objective of this study was to explore the correlation between mealiness of herbal drugs and its quality; licorice was selected as an example. Materials and Methods: The mealiness of licorice was graded by its weight; meanwhile, the content of glycyrrhizic acid and liquiritin was determined by high‑performance liquid chromatography‑diode‑array detection method; the content of polysaccharides, soluble sugars, pectin, total starch, amylose, and amylopectin was measured by colorimetric method; and the number and diameter of starch granule were observed by microscope. Results: The results showed that the mealiness of licorice which collected from wild and cultivated plants is positively correlated with the content of glycyrrhizic acid, liquiritin, the ratio of amylose to total starch, and the number of starch granules whose diameter was over 5 μm. However, the mealiness is negatively correlated with the total starch. Further, the formation mechanism of starch granule was discussed. Conclusion: It is for the first time to report the positive correlation between the mealiness and the starch granule size, the ratio of amylose to total starch, which can provide rationality for the quality evaluation using the character of mealiness in herbal medicine.