Vol. 42 No. 1, May 1930
No. of Page: 13
Philippine Eucalyptus Oil
By Augustus P. West and H. Taguibao
Bureau of Science, Manila
Eucalyptus trees are native of Australia where they form about three-quarters of the vegetation of that continent. The eucalyptus have been introduced into many other warm countries where they are now cultivated. Over three hundred species of eucalypts are known. These trees are evergreens and some of them occasionally reach a height of over 400 feet (122 meters). In Australia they are called gum trees, but the exudation from these trees is not really a gum but rather resembles an astringent tannin known locally as kino. Eucalyptus trees are valuable for rapidity of their growth, the usefulness of their timber, and the essential oils contained in their leaves.
Eucalyptus trees have been growing for some years in the highlands of the Philippines. Recently we distilled the leaves of various species of these eucalypts. When calculated on the weight of moist green leaves the yield of oil obtained varied from about 0.01 to 1.96 per cent. The highest yields of oil were obtained from Eucalyptus globulus, E. tereticornis, E. polyanthemos, and E. citriodora. Some of these trees gave over 4 per cent of eucalyptus oil calculated on a moisture-tree basis. The quality and cineol content of oil obtained from E. globulus compared favorably with that of oil distilled from the same species in Australia.
In Australia, Baker and Smith have carried out many investigations on the composition of oils obtained from numerous species of eucalyptus trees. Their results have shown that the essential oils obtained from different species may vary considerably in composition and also in yield. Oil obtained from definite species grown in different localities usually has a comparatively constant composition. According to these authors, "this constancy of constituents . . . . . " read more