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          Hog Creeper Vine Dry Extract is prepared from the powdered Hog Creeper Vine by extraction with ethanol (50 per cent).  It contains not less than 90.0 per cent and not more than 110.0 per cent of the labelled amount of genistein-7-O-[α-rhamnopyranosyl-(1^_→6)-β-glucopyranoside]; the labelled amount of genistein 7-O-[α-rhamnopyranosyl-(1^_→6)-β-glucopyranoside] is not less than 0.5 per cent, calculated as genistein (C₁₅H₁₀O₅) and  on the dried basis. 

Description  Yellowish to yellow-brown powder. 

Packaging and storage  Hog Creeper Vine Dry Extract shall be kept in well-closed containers, protected from light, and stored in a cool and dry place. 

Labelling  The label on the container states the equivalent amount of genistein-7-O- [α-rhamnopyranosyl-(1^_→6)-β-glucopyranoside], calculated as genistein; (2) the expiration
date.

Identification 

       A. To 500 mg of the sample, add 10 mL of methanol, boil in a water-bath for 5 minutes and filter.  To the filtrate, add 1 or 2 pieces of magnesium ribbon, shake well, mix with a few drops of hydrochloric acid, and warm in a water-bath:  a reddish brown colour develops.

       B. To 500 mg of the sample in a test-tube with screw-capped, add 10 mL of water and shake for 30 seconds:  a persisting foam is produced for over 15 minutes.

Loss on drying  Not more than 6.0 per cent w/w after drying at 105° to constant weight; use 1.0 g (Appendix 4.15). 

Assay Carry out the test as described in the “Liquid Chromatography” (Appendix 3.5). 
      Mobile phase A  Use acetonitrile.   
      Mobile phase B  Prepare a 1 per cent v/v solution of acetic acid.
          Standard preparation  Dissolve about 5 mg of Genistein RS, accurately weighed, in ethanol (50 per cent), dilute to 50.0 mL and mix.  Transfer 2.0 mL of this  solution to a 20-mL volumetric flask, dilute with the same solvent to volume, mix and filter.
       Assay preparation  Transfer about 500 mg of Hog Creeper Vine Dry Extract, accurately weighed, to a 200-mL volumetric flask, add about 150 mL of ethanol (50 per cent), sonicate for 30 minutes, dilute to volume, and mix.  Transfer 5.0 mL of this solution to a 10-mL volumetric flask, dilute with the same solvent to volume, mix, and filter.
       Chromatographic system  The chromatographic procedure may be carried out using (a) a stainless steel column (25 cm x 4.6 mm) packed with octadecylsilane chemically bonded to porous silica or ceramic microparticles (3 to 10 μm) equipped with the similarly packed guard column, (b) Mobile phase at a flow rate of about 1 mL per minute (the retention time is about 32 minutes for genistein.) and (c) an ultraviolet photometer set at 260 nm.  The step gradient of mobile phases is as follows: 

      To determine the suitability of the chromatographic system, chromatograph Standard preparation, and record the peak responses as directed for Procedure:  the relative standard deviation for replicate injections is not more than 2.0 per cent, the symmetry factor is not more than 2.0 per cent and the relative retention times are about 0.5 for genistein 7-O-[α-rhamnopyranosyl-(1^_→6)-β-glucopyranoside] and 1.0 for genistein. 

       Procedure  Separately inject equal volumes (about 20 μL) of Standard preparation and Assay preparation into the chromatograph, record the chromatograms and measure the responses for the major peaks.
       Calculation Calculate the content of genistein-7-O-[α-rhamnopyranosyl-(1^_→6)-β-glucopyranoside], calculated as genistein, in the portion of the Extract taken, using the declared content of C₁₅H₁₀O₅ in Genistein RS. 

Other requirements  Complies with the requirements described under “Extracts” (Appendix 1.16H).