Myrrh Absolute

#### Myrrh Absolute. A true **Absolute**** ****of**** ****Myrrh**** **should be prepared from myrrh resinoid (see monograph) by alcohol extraction and subsequent evaporation of the chilled and filtered extract. However, the usual method of producing an alcohol-soluble extract of myrrh, is the direct alcohol-extraction of the crude botanical. The resulting product which in pharmaceutical terms would be an extract, is commercially known as a “resin-absolute”. There are various types of resin-absolute according to the method of extraction. The comminuted crude Myrrh is treated with cold or lukewarm ethyl alcohol, the extracts are mixed, filtered and chilled after a precipitation period. The extract is then produced by evaporation under reduced pressure. The so-called “hot-extraction” yields a different “resin-absolute”. Its advantage is in the reduced extraction time, its disadvantage in the fact that certain components of the crude myrrh are dissolved which at a later moment will not dissolve readily in cold alcohol. The natural resin-acids form small amounts of odorous esters with the alcohol, thereby influencing the overall odor of the extract. Accordingly, cold-extracted “resin-absolutes” are preferred for their true-to- nature odor and good solubility. They may show a superior odor strength in many cases since they contain less of the odorless resinous components than do the hot-extracted products. Besides, cold-extracted resin-absolutes are generally lighter in color. A solvent-free resin-absolute of myrrh is not pourable at room temperature. This is a drawback in perfume compounding and handling of the material. It is customary to adjust the amount of liquid phase in the extract in the following manner: Towards the end of the evaporation, a high- boiling, odorless solvent is added which acts not only protectively against “burning” of the residual extract in the evaporator, but also as a plasticizer so that the **Myrrh Absolute **becomes pourable at room temperature and more handy in compounding operations. In this case, it is correct to label clearly how much solvent has been added, e.g. **“Myrrh Absolute, **75%, with 25% **Diethyl Phthalate**”, or the like. It is not correct to omit all mention of diluent. If the alcoholic extracts are prepared “cold” (i.e. room temperature), and the mixed extracts are not evaporated, one may obtain a concentrated **Tincture of Myrrh**. Starting with 20 parts of crude myrrh, and ending up with 100 parts of alcoholic extract, it is customary to label the product “**Myrrh Tincture**, 20%”. The content of extractive matter (i.e. essential oil + resin) in this tincture will be about 6 to 8 percent since the alcohol-insoluble gum is disposed of. Myrrh tinctures are used in pharmaceutical and dental preparations, rarely in perfumery. **Myrrh Absolute **is a very dark reddish-brown or orange-colored, viscous mass, only slightly more plastic than the resinoid. The absolute, if free from solvents or plasticizers, is not pourable, but it should be soft and sticky at room temperature. Its content of essential oil may be as high as 18 to 20%, in rare cases, higher. Stronger tinctures of myrrh can be prepared either directly from the crude Myrrh, or by dissolving myrrh absolute in the required amount of alcohol. The latter solution is even more easily achieved when the alcoholic extracts of myrrh, during the preparation of cold-extracted **Myrrh Absolute**, are evaporated to a previously calculated weight. This processing requires accurate knowledge of the yield of alcohol-soluble matter in the myrrh in order to prepare a uniform concentrated **Myrrh Tincture**. *Example: *1000 grams of **Myrrh **is extracted with alcohol until the last menstruum (i.e. fresh alcohol) does not dissolve any more of the myrrh. In this part of the process there is a distinct difference between “hot” extraction and “cold” extraction. The hot process is usually carried out as a boiling of the myrrh and alcohol under reflux. The temperature in this mixture will be considerably in excess of 80°C. Cold extraction is carried out under vigorous stirring of the comminuted myrrh with alcohol at room temperature. A few manufacturers may use percolation of a mixture of washed sand and comminuted myrrh with alcohol. The sand prevents “clogging” of the myrrh with the saturated resin-solution during the beginning of the extraction. The mixed extracts are filtered and weighed. The weight is 4300 grams (example). A preliminary, small-scale extraction of the same **Myrrh**** **has shown that it contains 30% alcohol-soluble matter. Our alcoholic extract is then evaporated under suitable vacuum until the pot residue is 600 grams. The finished product is a viscous, dark-orange or reddish liquid which represents a 50% solution of **Myrrh**** ****Absolute,**** **it can also be called **Myrrh**** ****Extract**** **6 = 10, which means that 6 parts of our extract contains the soluble ingredients from 10 grams of **Myrrh**. A true and purified **Absolute of Myrrh **can be produced by hot extraction (reflux) of the comminuted myrrh with a hydrocarbon solvent. A resinoid is prepared by evaporation of this extract. If the hydrocarbon extract is washed free from resin-acids with weak aqueous alkali prior to evaporation, a neutral resinoid is produced. This may subsequently be extracted with hot alcohol to produce a “purified” absolute. The yield is significantly smaller than the yield by ordinary and total extraction, but the product is superior in respect to odor and performance in soaps, etc. The purified absolutes are generally lighter of color. **Myrrh Absolute **or concentrated **Myrrh Extracts **are used in perfumery in circumstances similar to those described under **Myrrh Resinoid**. They have a lower acid index and slightly higher essential oil content than the resinoids, and they are soluble in all perfumery materials. **Myrrh**** ****Extracts**** **which contain alcohol are not clearly soluble in vegetable oils or mineral oil and they may cause slight turbidity with certain other solvents occasionally used in perfumery. The extract mentioned in the above example can be made oil-soluble if a calculated amount of diethyl phthalate is introduced prior to the evaporation of the alcoholic extract. The alcohol may then be recovered quantitatively, leaving the high-boiling solvent in the extract.