This section is from the book "A Text Book Of Materia Medica, Being An Account Of The More Important Crude Drugs Of Vegetable And Animal Origin", by Henry G. Greenish. Also available from Amazon: A Text Book of Materia Medica : Being an Account of the More Important Crude Drugs of Vegetable and Animal Origin.
The term ' elemi' is a generic one and is applied to a number of oleo-resins having certain physical properties in common. Tschirch enumerates no fewer than 46 varieties, all of which are derived from plants belonging to the natural orders Burseraceoe or Butacoe. The most important and formerly official variety is exported from Manila and distinguished as Manila elemi.
Manila elemi is an oleo-resin obtained from a species of Canarium, probably C. luzonicum, Gray (N.O. Burseraceoe). It is obtained by making incisions in the tree and promoting the flow of oleo-resin by the application of heat. When first obtained it is probably a clear, viscid, honey-like liquid which, however, rapidly becomes crystalline. It is exported chiefly from Manila, and arrives in this country in tins or lead-lined cases, in a more or less solid condition.
Elemi when fresh and of good quality is pale yellow in colour, soft and granular, resembling a crystalline honey, but on keeping it gradually becomes darker in colour, firmer and finally hard. It is soluble in alcohol and ether, partially only in petroleum spirit. It has a fragrant, balsamic odour recalling fennel and mace, and a spicy, rather bitter taste. Under the microscope it is seen to contain an abundance of acicular crystals.
Manila elemi, in the soft condition in which it is usually imported, contains about 20 to 30 per cent, of volatile oil associated with amorphous and crystalline resin acids, bitter principle, etc.
The volatile oil (sp. gr. 0.87 to 091) consists chiefly of terpenes; the aromatic constituents have not been examined.
The resin contains a- and β-manelemic acids (soluble in solution of ammonium carbonate), a- and β-manamyrin (insoluble in ammonium carbonate and in alcohol), maneleresene (insoluble in ammonium carbonate, soluble in alcohol), bryoidin, and bitter principle. The composition of the drug may be seen from the following table:
a-Manelemic acid ...
5 to 6
β-Manelemic acid ...
8 to 10
a- and β-Manamyrin ...
20 to 25
30 to 35
Volatile oil ...
20 to 25
Bitter principle and impurities .
6 to 8
α-Manelemic acid is crystalline and forms crystalline salts; a- and β-manamyrin are both crystalline, as is also bryoidin.
Elemi has been employed in the form of ointment, as a stimulant and antiseptic application. It is now seldom prescribed.
East African Elemi, from Boswellia Frereana, Bird-wood (Somaliland); in stalactitic masses; fragments pale amber yellow.
Brazilian Elemi, from Protium heptaphyllum, March (N.O. Bur-seraceoe); small brown nodules, almost free from odour, mixed with fragments of bark.
Yucatan Elemi, from Amyris Plumerii, de Candolle (N.O. Bur-seraceoe); yellow translucent pieces curved on one side, very aromatic.
All these varieties of elemi resemble Manila elemi in composition.