Red Rhodiola

Crude Drug Identification

Identification

1. Microscopic Identification

(1) Cross-section of the root: The cork layer consists of 5–8 rows of cells; the cells of the inner cork layer are elliptical or subcircular. The stele occupies the vast majority of the cross-section and contains numerous vascular bundles arranged in 2–4 concentric rings. The outer ring of vascular bundles is larger and of the exarch type; the inner 2–3 rings of vascular bundles gradually decrease in size and are of the pericycle type.

(2) Cross-section of the rhizome: Mature rhizomes have 2–3 cork layer bands, while young rhizomes lack cork layer bands. The cork layer consists of several rows of cells, and the inner cork layer is not distinct. The cortex is narrow. The vascular bundles in the stele are large, pericyclic, and arranged in radial rings;the vascular tissues on the inner and outer sides of the vascular bundles are well-developed and arranged in opposite rows, with parenchyma in between; the phloem and xylem are nearly equal in length and are separated by secondary rays into slender strips; the cambium is distinct. The pith is broad, composed of parenchyma cells, with scattered pericyclic pith vascular bundles. The parenchyma cells contain brown secretions.

2. Physicochemical Identification

Weigh approximately 0.5 g of the powdered sample (passed through a No. 3 sieve) with precision, place it in a stoppered conical flask, add 10 mL of methanol with precision, seal tightly, and weigh the flask. Subject the mixture to ultrasonic treatment for 30 minutes, allow to cool, and weigh the flask again. Make up for the weight loss with methanol, shake well, filter, and take the filtrate as the test solution.Take an appropriate amount of Rhodiola glycoside reference standard, weigh it accurately, and dissolve it in methanol to prepare a solution containing 0.5 mg per mL; use this as the reference solution.Perform the test according to the Thin-Layer Chromatography method (General Chapter 0502). Pipette 10 μL each of the reference solution and the test solution and apply them separately to the same silica gel G plate. Develop using the lower layer of the mobile phase consisting of chloroform–methanol–acetone–water (6:3:1:1).until a distance of 18 cm is reached. Remove the plate, allow it to air-dry, and expose it to iodine vapor. In the test sample chromatogram, spots of the same color appear at positions corresponding to those in the reference standard chromatogram.

Properties of Crude Drugs

The rhizome is cylindrical, thick and short, slightly curved, with a few branches; it is 5–20 cm long and 2.9–4.5 cm in diameter. The surface is brown or dark brown, rough, and wrinkled; when the outer epidermis is peeled off, a membranous yellow epidermis with pink mottling is revealed. Remnants of old flower stalks are present, with the bases of the flower stalks covered by triangular or ovate membranous scales;The internodes are irregular; the cross-section is pink to purplish-red with a ring-like pattern; the texture is light and loose. The main root is cylindrical, thick and short, approximately 20 cm long, with an upper diameter of about 1.5 cm; lateral roots are 10–30 cm long; the cross-section is orange-red or purplish-red, sometimes with fissures. It has an aromatic odor and a slightly bitter and astringent taste that turns sweet afterward.

Properties of Processed Slices

The roots are round, subcircular, or irregularly lobed; the outer epidermis is brown, reddish-brown, or brown; in some specimens, peeling away the outer epidermis reveals a membranous yellow inner layer with pinkish patterns. The cross-section is pinkish to purplish-red, sometimes with fissures. The texture is light and loose. It has a fragrant aroma and a slightly bitter and astringent taste, followed by a sweet aftertaste.