Atractylodes Rhizome
Atractylodis Rhizoma
Atractylodes Rhizome is the rhizome of Atractylodes japonica Koidzumi ex Kitamura (Wa-byakujutsu), or is the rhizome of Atractylodes macrocephala Koidzumi (Atractylodes ovata De Candolle) (Kara-byakujutsu) (Compositae).
Description:
(1) Wa-byakujutsu.Periderm-removed rhizome is irregular masses or irregularly curved cylinder, 3 – 8 cm in length, 2 . 3 cm in diameter; externally light grayish yellow to light yellowish white, with scattered grayish brown parts. The rhizome covered with periderm is externally grayish brown, often with node-like protuberances and coarse wrinkles. Difficult to break, and the fractured surface is fibrous. A transverse section, with fine dots of light yellow-brown to brown secrete.
Odor, characteristic; taste, somewhat bitter.
Under a microscope, a transverse section reveals periderm with stone cell layers; fiber bundles in the parenchyma of the cortex, often adjoined to the outside of the phloem; oil sacs containing light brown to brown substances, situated at the outer end of medullary rays; in the xylem, radially lined vessels, surrounding large pith, and distinct fiber bundle surrounding the vessels; in pith and in medullary rays, oil sacs similar to those in cortex, and in parenchyma, crystals of inulin and small needle crystals of calcium oxalate.
(2) Kara-byakujutsu.Irregularly enlarged mass, 4 - 8 cm in length, 2 - 5 cm in diameter; externally grayish yellow to dark brown, having sporadic, knob-like small protrusions. Difficult to break; fractured surface has a light brown to dark brown xylem remarkably fibrous.
Odor, characteristic; taste, somewhat sweet, but followed by slight bitterness.
Under a microscope, a transverse section usually reveals periderm with stone cells, absence of fibers in the cortex; oil sacs containing yellow-brown contents in phloem ray and also at the outer end of it; xylem with radially lined vessels surrounding large pith, and distinct fiber bundle surrounding the vessels; pith and medullary ray exhibit oil sacs as in cortex; parenchyma contains crystals of inulin and small needle crystals of calcium oxalate.
Identification:
Macerate 0.5 g of pulverized Atractylodes Rhizome with 5 mL of ethanol (95) by warming in a water bath for 2 minutes, and filter. To 2 mL of the filtrate add 0.5 mL of vanillin-hydrochloric acid TS, and shake immediately: a red to red-purple color develops and persists.
Purity:
(1) Arsenic . Prepare the test solution with 0.40 g of pulverized Atractylodes Rhizome according to Method 4, and perform the test (not more than 5 ppm).
(2) Atractylodes lancea rhizome.To 2.0 g of pulverized Atractylodes Rhizome add exactly 5 mL of hexane, shake for 5 minutes, filter, and use this filtrate as the sample solution. Perform the test with the sample solution as directed under Thin-layer Chromatography. Spot 10 μL of the solution on a plate of silica gel for thin-layer chromatography. Develop the plate with a mixture of hexane and acetone (7:1) to a distance of about 10 cm, and air-dry the plate. Spray evenly 4-dimethylaminobenzaldehyde TS for spraying on the plate, and heat at 100oC for 5 minutes: no green to grayish green spot appears at the Rf value of between 0.3 and 0.6.
Total ash:
Not more than 7.0z.
Acid-insoluble:
Not more than 1.0z.
Essential oil content:
Perform the test with 50.0 g of pulverized Atractylodes Rhizome: the volume of essential oil is not less than 0.5 mL.
Containers and storage:
Containers.Well-closed containers.
