Patent GB-672874-A (GB)
Title: Process for the preparation of crystalline active principle from garlic
IPC: A61K36/8962
Filed: 1947-12-31
Abstract: In a process for the preparation from bulbs or cloves of garlics of a crystalline odourless active principle containing sulphur and nitrogen, the fresh undried material is ground whilst frozen and extracted with an alcohol containing not more than three carbon atoms, which is then distilled off and the remaining aqueous extract is either (a) treated with phenols or aliphatic carboxylic acids which are either liquid or which become liquid in contact with water, and are not wholly miscible with water, which are then separated together with the dissolved active principle from the aqueous layer, the aforesaid phenols or aliphatic carboxylic acids are removed by treating the solution with an aliphatic ether containing not more than eight carbon atoms or a chlorinated aliphatic hydrocarbon containing not more than two carbon atoms and the active principle is obtained from the remaining syrupy aqueous layer after evaporation to small volume in vacuo by adding a solvent which is acetone or a saturated alcohol containing not more than three carbon atoms, or (b) treated with a substantially anhydrous lower aliphatic alcohol containing not more than three carbon atoms and the aqueous alcoholic extract, after separation from the precipitated syrup containing a portion of the impurities, is evaporated to dryness preferably under diminished pressure, the impurities which are present in the residue are removed by extraction with anhydrous methanol and the active principle is obtained from this residue by crystallization from dilute acetone or a dilute aliphatic alcohol containing not more than three carbon atoms.  Methyl and ethyl alcohols are suitable lower alcohols, phenol, cresol, valeric and capronic acids are suitable phenols or aliphatic carboxylic acids. In examples, garlic cloves are frozen, mixed with solid carbon dioxide and ground and twice extracted with methyl alcohol whilst warming.  The extracts are in example (1) evaporated and centrifuged and the fatty layer rejected. The dark-coloured syrup is extracted twice with phenol just liquefied by the addition of water.  Further water is added and the whole stirred into ether and the separated aqueous syrupy solution is further extracted with ether and evaporated in vacuo.  The desired product is obtained by adding methyl alcohol to the residue and cooling.  In example (2) the extracts are concentrated, extracted with ether and again evaporated in vacuo.  The concentrate is poured into anhydrous ethyl alcohol.  A yellow syrup is separated and the supernatant alcoholic solution evaporated to dryness in vacuo. The residue is extracted with methyl alcohol and ether and is recrystallized from water and acetone.  The product melts at 163-165 DEG  C., is dextrorotatory [a ]D21=+62.8 DEG  C=2, and the empirical formula is C6H11O3NS. 1/2 H2O.  In aqueous solution a red colour is produced with alloxan and a positive ninhydrine reaction is obtained. On treating the product with an enzymatic solution prepared from garlic an anti - bacterial action ensues.  Specification 235,883, [Class 81 (i)], is referred to.