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Category  Sedative.

       Valerian is a dried, whole or fragmented underground parts of Valeriana officinalis L. (Family Valerianaceae), carefully dried at a temperature below 40°, including the rhizome surrounded by the roots and stolons.  It yields not less than 0.4 mL of volatile oil from each 100 g of drug and contains not less than 0.17 percent w/w of sesquiterpenic acids, calculated as valerenic acid, C₁₅H₂₂O₂, on the dried basis.

Origin of plant  Valerian is native to Eurasia, especially in damp woods, ditches and along the streams in Europe.

Constituents  Valerian contains valepotriates and sesquiterpenes of the volatile oil, such as acetoxyvalerenic acid, valerenic acid and valerenal.

Description  Odour, characteristic, penetrating, resembling that of valeric acid and camphor; taste, initially sweetish then camphoraceous and slightly bitter.
Macroscopical  Rhizome:  entire or longitudinally cut , 2 to 5 cm long, 1 to 3 cm in diameter, yellowish grey to greyish brown; base elongated or compressed, covered by and merging with numerous roots; apices usually bearing cup-shaped scars from aerial parts; stem base rarely present; fracture revealing pith with a central cavity; longitudinal cut showing transverse septum.  Roots, numerous, yellowish grey to greyish brown with longitudinal stripes, slender, cylindrical, about 10 cm long and up to 3 mm in diameter, with a few filiform, fragile secondary root; fracture, short.  Stolon pale yellowish grey, showing prominent nodes separated by longitudinally striated internodes, each of which 2 to 5 cm long; fracture fibrous.
Microscopical  Transverse section of the rhizome shows epidermis, cork, cortex, endodermis, pericycle, vascular bundles, and xylem.  Epidermis:  slightly thick-walled polygonal cells.  Cork:  up to 7 layers of slightly suberized, large, polygonal, brownish cells.  Cortex:  thick-walled parenchyma containing numerous starch granules and traversed by numerous root traces.  Endodermis:  a single layer of tangentially elongated cells containing volatile oil globules.  Pericycle, parenchymatous.  Vascular bundle, collateral, in a ring and surrounding a very large parenchymatous pith, containing starch granules and sometimes scattered groups of pitted, thick-walled sclereids with a narrow lumen.  Xylem, with few slender, annular, spiral and pitted vessels. 
Transverse section of the branch shows components similar to those of the rhizomes, but with a prominent endodermis and a well-defined ring of vascular bundles showing secondary thickening.
Transverse section of the root shows a piliferous layer of papillose cells, exodermis, cortex, endodermis, and primary xylem.  Piliferous layer of papillosed cells, some developed into root hairs.  Exodermis:  a single layer of suberized-walled quadrangular to polygonal cells containing volatile oil globules.  Cortex:  parenchyma cells with numerous starch granules; the outermost cells containing volatile oil globules.  Endodermis:  a layer of radially thick-walled cells.  Primary xylem:  3 to 11 arches surrounding a small central parenchymatous pith containing starch granules, sometimes showing a cleft or stellate hilum. 
Powdered drug of Valerian Root possesses the microscopical characteristics of the unground drug with abundant simple or 2- to 6-compound starch granules characterized by an indistinct cleft or a radiate hilum.

Packaging and storage  Valerian shall be kept in well-closed containers, protected from light and stored in a cool and dry place.

Identification
Carry out the test as described in the “Thin-Layer Chromatography” (Appendix 3.1).
     Standard solution   Dissolve 5 mg of acetoxyvalerenic acid and 5 mg of valerenic acid in 20 mL of methanol.
     Test solution  Suspend 1 g of the powdered drug in 10 mL of methanol and sonicate for 10 minutes.  Filter the supernatant through a 0.45-µm membrane filter.  Use the filtrate.
     Adsorbent  Silica gel G (TLC or HPTLC plate).
     Mobile phase  Glacial acetic acid, ethyl acetate, and cyclohexane (2:38:60).
     Application  Apply 20 µL (or 5 µL) each of Standard solution and Test solution as 10-mm (or 8-mm) bands.
     Development and drying  Allow the solvent front to ascend 10 cm (or 6 cm) above the line of application.  Dry the developed plate in air.
     Detection  Spray the plate with anisaldehyde TS, heat at 105° for 5 to 10 minutes and examine immediately under visible light.  Observe the result.
     Results  When examined under visible light, the test solution shows a violet band due to acetoxyvalerenic acid in the lower third and a violet band due to valerenic acid in the upper third of the chromatogram, corresponding in colour and R_f to the bands shown by the standard solution. 

Loss on drying  Not more than 12.0 per cent w/w after drying at 105° for 2 hours (Appendix 4.15).

Acid-insoluble ash  Not more than 5.0 per cent w/w (Method II, Appendix 7.6).

Total ash  Not more than 12.0 per cent w/w (Appendix 7.7).

Assay
FOR VOLATILE OIL  Carry out the method for the “Determination of Volatile Oil” (Appendix 7.3), using 40 g, in No.500 powder, freshly prepared and accurately weighed.  Use 500 mL of water as the distillation liquid and a 2000-mL flask.  Distil at a rate of 3 to 4 mL per minute for 4 hours.  Use 0.50 mL of xylene in the graduated tube.
FOR SESQUITERPENIC ACIDS   Carry out the determination as described in the “Liquid Chromatography” (Appendix 3.5). 
     Standard preparation  Dissolve Valerian Dry Extract RS in methanol to contain 1.0 mg of valerenic acid and dilute to 10.0 mL with the same solvent.  Sonicate for 10 minutes and filter through a 0.45-µm membrane filter. 
     Assay preparation  Transfer about 1.5 g of Valerian, in No. 710 powder, accurately weighed, to a 100-mL round-bottomed flask with a ground-glass neck.  Add 20 mL of methanol.  Mix and heat on a water-bath under a reflux condenser for 30 minutes.  Allow to cool and filter.  Transfer the filter with the residue to the 100-mL round-bottomed flask.  Add 20 mL of methanol and heat on a water-bath under the reflux condenser for 15 minutes.  Allow to cool and filter.  Combine the filtrates and dilute to 50.0 mL with methanol, rinsing the round-bottomed flask and the filter.
     Mobile phase
          MOBILE PHASE A  Acetonitrile for chromatography and a 0.5 per cent w/v solution of phosphoric acid (20:80).
          MOBILE PHASE B  Acetonitrile for chromatography and a 0.5 per cent w/v solution of phosphoric acid (80:20).

The step gradient of mobile phases is as follows:

                   Chromatographic System
                        DETECTOR  Ultraviolet light (220 nm) 
                        COLUMN  A stainless steel column (25 cm × 4.6 mm), packed with octadecylsilyl bonded to porous silica or ceramic microparticles (5 µm).
                        COLUMN TEMPERATURE   35°
                        FLOW RATE  1.5 mL per minute
                   System Suitability
                        Sample Standard preparation  
(Note  The relative retention with reference to valerenic acid for acetoxyvalerenic acid is about 0.5, where the retention time for valerenic acid is about 19 minutes.)
Procedure  Separately inject equal volumes (about 20 mL) of Standard preparation and Assay preparation into the chromatograph, record the chromatograms,  and measure the responses for the major peaks.  Identify the peaks due to acetoxyvalerenic acid and valerenic acid in the assay preparation using the retention time of acetoxyvalerenic acid and valerenic acid in the standard preparation.
Calculation  Calculate the contents of sesquiterpenic acids, calculated as valerenic acid, using the following expression:

 (A_u1+A_u2)W(5P) ,

A_sw

in which A_u1 and A_u2 are the areas of the peak due to acetoxyvalerenic acid and to valerenic acid obtained from Assay preparation; A_s is the area of the peak due to valerenic acid obtained from Standard preparation; w is the weight, in g, of Valerian in Assay preparation, W is the weight, in g, of Valerian Dry Extract RS in Standard preparation; P is the declared content of C₁₅H₂₂O₂ in Valerian Dry Extract RS.

VALERIAN, POWDERED

Complies with the requirements for Contents of volatile oil and valerenic acid, Packaging and storage, Identification, Loss on drying, Acid-insoluble ash, and Total ash stated under Valerian and with the following requirement.

Description  Light brown.  Diagnostic structures:  numerous fragments of parenchyma composed of rounded or elongated cells containing simple or 2- to 6-compound starch granules; occasional cells filled with light brown resin; rectangular sclereids with pitted walls, 5 to 15 µm thick; xylem vessels isolated or in small groups, 10 to 50 µm in diameter; root hairs and fragments of cork also present.