Identification method of licorice extract

Licorice Extract is a medicinally valuable ingredient extracted from licorice
.

The licorice extract generally contains: glycyrrhizin, glycyrrhizic acid, licorice, licorice flavonoids, cinnabar, formononetin, quercetin,
etc.

Identification method of licorice extract: (1) The cross section of this product: the cork layer is a series of brown cells
.

The cortex is narrow
.

The rays of the phloem are broad, more curved, and often have cracks; the fibers are mostly bundled, not lignified or slightly lignified, and the surrounding parenchyma cells often contain calcium oxalate cubes; the sieve tube group is often deformed by compression
.

Intrabundle cambium is evident
.

The xylem rays are 3 to 5 rows of cells wide; there are many vessels, and the diameter is about 160 μm; the wood fibers are bundled, and the surrounding parenchyma cells also contain calcium oxalate cubes
.

Root center without pith; rhizome center with pith
.

Powder light brownish yellow
.

The fibers are bundled with a diameter of 8-14 μm, the wall thickness is slightly lignified, and the surrounding parenchyma cells contain calcium oxalate square crystals to form crystal fibers
.

Calcium oxalate crystals are more common
.

The bordered pit ducts are larger, and the reticulate ducts are rare
.

Cork cells reddish brown, polygonal, slightly lignified
.

(2) Take 1 g of this product powder, add 40 ml of ether, heat under reflux for 1 hour, filter, add 30 ml of methanol to the drug residue, heat under reflux for 1 hour, filter, evaporate the filtrate to dryness, add 40 ml of water to the residue to dissolve, and extract with n-butanol 3 times, 20ml each time, combine n-butanol solution, wash 3 times with water, evaporate to dryness, add 5ml methanol to the residue to dissolve, and use it as the test solution
.

In addition, 1 g of licorice reference medicinal material was taken, and the reference medicinal material solution was prepared by the same method
.

Then take the ammonium glycyrrhizinate reference substance, add methanol to make a solution containing 2mg per 1ml, as the reference substance solution
.

According to the thin-layer chromatography (Appendix VI B) test, draw 1-2 μl of each of the above three solutions, and place them on the same silica gel G thin-layer plate prepared with 1% sodium hydroxide solution.
Acetic acid-water (15:1:1:2) was used as the developing agent, unfolded, taken out, air-dried, sprayed with 10% sulfuric acid ethanol solution, heated at 105 ℃ until the spot color was clear, and inspected under ultraviolet light (365nm)
.

In the chromatogram of the test substance, the fluorescent spots of the same color are displayed on the corresponding positions of the chromatogram of the reference medicinal materials; the same orange-yellow fluorescent spots are displayed on the corresponding positions of the chromatogram of the reference substance
.