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160 A. E. PARKES AND F. MAJOR: THE COMPOSITION AND

THE COMPOSITION AND ANALYSIS OF COMPOUND LIQUORICE POWDER. BY A. E. PARKES, F.I.C., AND E”. MAJOR, B.Sc. (Read at the Meeting, March 4, 1914.) THEanalysis of compound liquorice powder, which is a mixture of senna, liquorice root, fennel fruit, sublimed sulphur, and refined sugar, offers some difficulty to the analyst . No method of analysis or analytical standards are recommended by the Pharmacopceia ; and although several analysts have endeavoured to remedy these omissions (Liverseege, Year-Book of Pharmacy, 1906, 269 ; Scott-Smith and Evans, ANALYST,1911, 36, 1981, the only suggested standards at present available are those for moisture, ash, and extract (Gadd, Yeur-Kook of Pharmacy, 1901, 390; Moor, ‘‘ Suggested Standards for Foods and Drugs ”). A large number of samples of compound liquorice powder have been examined by us, and our method of examination has been devised with the object, as far as possible, of endeavouring to ascertain the quality of each ingredient, and also with a view to detecting the presence of exhausted drugs. Samples of senna, liquorice root, and fennel fruit, of undoubted purity were procured, and from these powdem were made up and examined similarly, the figures obtained being compared with those calculated from the several ingredients after they had been individually submitted to the same process, This method, of which the following is a description, can be advantageously used where the amount of sample available is limited in quantity. Chemical Examination.-Moisture and ash are estimated by the usual methods on the same portion (I grm.). The soluble ash and alkalinity of same may also be estimated; but the figures for these are of little value, owing to the disturbing influence of the sulphur (Evans, Pharm. J., 1905, 74, 363). The carbon disulphide extract is obtained by exhausting 5 grrns. with dry carbon

Published on 01 January 1914. Downloaded by University of Massachusetts - Amherst 25/10/2014 14:46:13. disulphidefor twelve hours in a Soxhlet. The sulphur in this extract is estimated by oxidising it with fuming nitric acid, and precipitating the sulphuric acid with barium chloride solution in the usual manner. The difference between the sulphur and the total extract is principally oil from the fennel, the senna and liquorice only yielding a comparatively small quantity of extract to carbon disulphide. The extracted powder, a,fter drying, is mixed with water and made up to a, volume of 250 c.c., and allowed to digest, with occasional shaking, for twelve hours. It is then left to settle and the supernatant liquid filtered. The aqueous extract is obtained by evaporating 50 C.C. of this filtrate, representing 1 grm. of powder, to dryness. Sugar is estimated by treating another 50 C.C. with lead acetate solution, and, after removal of the lead precipitate and excess of lead, polarising, or titrating with Fehling’s solution after inversion. The results are usually about 1 per cent. too low, The aqueous extract less sugar gives the extract from the combined drugs. A further 50 or 100 C.C. is submitted to what, for want of a better name, we have called the “ glycyrrhixin test.” The solution is acidified with a few drops of dilute View Article Online

ANALYSIS OF COMPOUND LIQUORICE POWDER 161 sulphuric acid, which precipitates glycyrrhizic acid and traces of other substances. When the precipitate has settled, the liquid is passed through a small filter, and the precipitate washed with a small quantity of cold water. The precipitate is then dissolved in dilute ammonia, passed through the same filter, which is afterward washed with a further quantity of the ammonia solution, the solution being then evaporated to dryness and the crude glycyrrhizin weighed.* Owing to the presence in the aqueous extract of small quantities of other closely allied bodies, it has been found impossible so far to isolate the glycyrrhizin in a pure state. At present no simple direct method suggests itself for the valuation of the senna, but, providing the carbon disulphide extract and the glycyrrhizin test are satisfactory, a low aqueous extract would point to the probability of the presence of exhausted senna. The presence of senna is indicated in the glycyrrhizin test. The sulphuric acid precipitates a small amount of material from the senna extract, which on being dissolved in the ammonia solution produces a fine cherry-red colour, easily observed even in the presence of the other colouring matters. This cherry-red colour is probably caused by those closely allied substances-chrysophanic acid and emodin- present in the senna (cf. Tutin, J. Chem. Soc., 1913, 103, 2006). It is not produced in the absence of senna, and we hope to investigate this reaction further to ascertain if it cannot be made available for the estimation of senna extract. For the estimation of the total sulphur, Squire (‘LCompanionto British Pharma- copia”) and Liverseege (ibid.) recommend extraction with carbon disulphide. The figure SO obtained is, however, at the best only approximately correct, though the loss in sulphur may be balanced by the fennel extract, Sublimed sulphur always contains a quantity of the insoluble variety, and we have found this in some commercial samples to amount to as much as 20 per cent. For the estimation, about 1 grm. of the powder is oxidised with fuming nitric acid and a little potassium nitrate or chlorate, as recom- mended by Alcock (Pharm. J., 1906, 77, 485) and Evans (&id.), and the sulphuric acid formed is precipitated with barium chloride. We have found this method to be successful in every case, and fairly rapid. The results obtained are generally about 0.1 per cent. too high. Published on 01 January 1914. Downloaded by University of Massachusetts - Amherst 25/10/2014 14:46:13. Substituted drugs must be sought for by the microscope. Microscopical Examination.-It is essential that the powder should be sub- jected to a thorough microscopical examination. Cf. Scott-Smith and Evans (&I.). The papers on senna by Greenish (Pharm. J.,1901,66,397) and Sayre (Am. J. Phawn., 1896, 68, 535-592; 1897, 69, 298-306) are also worthy of note. When examined in 50 per cent. chloral hydrate solution, and glycerol containing little iodine, the various structures are easily identified-the parenchymatous tissue and characteristic starch grains of the liquorice root, the typical one-celled warty hairs and stomata of the senna, and the oil cells and aleurone grains of the fennel fruit. With little experience it is possible to identify all the difYerent structures ; at the same time it is advisable to compere the powder with one made up with ingredients of known purity. The following list contains the maximum, minimum, and mean figures obtained on thirteen normal samples recently examined. The majority were purchased under the Sale of Food and Drugs Acts, and may be considered typical commercial samples. * This gives an indication of the quality of the liquorice root used. View Article Online

162 A. E. PARKES AND F. MAJOR : THE COMPOSITION AND The list also contains the figures obtained on the two prepared samples, and the calculated figures. TABLEI. -____ Standard Standard Maximum Minimum Mean. A. B. Calcuhted.

Per Cent. Per Cent. Per Cent. Per Cent. Per Cent. Per Cent. Loss at 100" C...... 7.9 3.0 4.7 3.3 3 *9 3 -8 Ash ...... 6-2 4.6 5-3 5.2 4.9 4.3 Carbon disulphide extract 10.7 9.2 10.3 9.7 9.5 9.7 Sulphur in extract ... 7.9 6.3 7.1 7.0 6-9 7 *1 Extract less sulphur .. . 3.6 2.6 3.1 2.7 2.6 2.6 Total sulphur ...... 9.2 7.8 8.6 8.5 8.6 8.4 Cold water extract ... 63-9 61.1 62.6 62.6 62.4 62.4 Ash of extract ...... 2.4 1*8 2 *o 1.9 1.9 2.0 Cane-sugar ...... 50.3 48.3 48.8 49.1 48.9 50.7 Extract less sugar ... 14.6 11.8 13.5 13.5 13.5 11.7 Crude glycyrrhizin .. . 2.9 1.2 1.9 2.7 2.6 2.0

So far we have not met with any case of substituted or exhausted drugs. Many cases of excess of sulphur and deficiency of sugar have been found which may have been due to careless mixing. For instance, we have found sulphur as high as 20 per cent., and sugar as low as 35 per cent. The drugs employed in making up the powders referred to above gave the following figures on examination : TABLE11.

A. B.

Fennel, Liquorice Seniia Liquorice Senna, Root, Alexan- Fennel, Nnnivelly Indian. opt. Roo dec. 2. drian. opt. Published on 01 January 1914. Downloaded by University of Massachusetts - Amherst 25/10/2014 14:46:13. ._~ -____ Per Cent. Per Cent. Per Cent. Per Cent. Per Cent. Per Cent. Loss at 100" c...... 8-2 9.1 8.9 9.1 10.5 10.1 Ash, total ...... 11.8 13.7 7.0 16.6 11.6 4.1

Insoluble ash ..I 8-8 8.3 5.2 13-3 7.4 1.9 Alkalinity of ash 3-0 C.C. 3.3 C.C. 1.6 C.C. 2.6 C.C. 3.5 C.C. 1.7 C.C. Carbon disulphide extract 6.4 16.1 1-3 2.9 20.0 0-8 Cold water extract ... 30.5 27.2 40.3 33.7 18-5 29.4 Ash of extract ...... 5.9 7 *3 2.5 5.8 4.3 2.4 Crude glycyrrhizin f- .. . (3.6) (0.5) 7.2 (1.7) (1.8) 7.3 Sugars ...... * 1.1 1.8 3.3 1.0 1.8 2.2 Sulphur ...... 0.08 0.37 0.04 0.28 0.41 0.33 Nitrogen ...... 2.34 2.32 1.75 2.31 2.81 1.54 p205 ...... 0.22 1.21 0.09 0.42 1.12 0.22

* The amount of acid required to neutralise the ash from 1 grm. of material, expressed in C.C. of 2: solution. 10 t The figures in parentheses represent the percentage of solids obtained by the glycyrrhizin test. View Article Online

ANALYSIS OF COMPOUND LIQUORICE POWDER 163

DISCUSSION. Mr. E. J. PARRYremarked that the proportion of glycyrrhizin in different kinds of liquorice-or at any rate in the extract therefrom, commonly known as liquorice juice-was very variable. For example, the extract from the Spanish root contained about 5 to 7 per cent. of glycyrrhizin ; that, from Sicilian root about 9 to 13 per cent. ; while the least valuable kind-namely, Smyrna root-yielded an extract containing 18 to 22 per cent. of glycyrrhizin. It would therefore be seen that the proportion of glycyrrhizin was by no means an index of the quantity of liquorice present. Moreover, the authors gave results obtained by the glycyrrhizin test in the case of the fennel and senna, but these substances contained no glycyrrhizin at alI. Mr. PARKESsaid that he quite agreed with Mr Parry as to the variation in the percentage of glycyrrhizin in liquorice root ; but in the compound powders that they had examined the figures were smaller and the variations not so great. The average figure was 1.9, and those given by the standard samples 2.6 and 2.7. According to their calculations, it should be about 2, including the precipitate yielded by the senna

and the fennel. They called this 6‘ crude glycyrrhizin,” it being of course obvious that it was not pure. It was the liquorice, however, that made the chief difference, since the quantities of fennel and senna were comparatively small, and the figures yielded by these ingredients were themselves also small. Published on 01 January 1914. Downloaded by University of Massachusetts - Amherst 25/10/2014 14:46:13.