The sandal tree (Santalum album L.) is expoited mainly for its scented heartwood which gives the fragrant sandalwood oil upon steam distillation. Yields are from 2.5-6.2% depending upon the age of the tree and the color of heartwood. The great fixative property and the tenacious aroma of sandalwood oil principally are because of its major odoriferous sesquiterpenic constituents—alpha and beta santalol, forming more than 90% of the oil. Some minor constituents like alpha and beta santalene (1.5-3.0%) and other oxygenated sesquiterpenes (2.5-4.0%) to some extent also contribute to the overall odor character of the oil.
Analysls of the Study
During the analysis of a large number of heartwood samples, we encountered some well grown sandal trees, producing heartwoods, which are less scented. On distillation, the heartwood of these trees produced a reduced amount of essential oil (1.5-3.0%). This lower oil content also was reflected in reduced amounts of alpha- and beta-santalol (65-75%) and increased amounts of alpha- and beta-santalene (5-8%), and other oxygenated sesquiterpenes (5-12%). These oils possess a poor odor quality as compared with the normal sandalwood oil. Because of this and their reduced santalol content, these oils have not been accepted as raw materials in the cosmetic and fragrance industries.
In the present study, the utilization of these less odorous sandalwood oil samples is examined. It has been found that direct esterification of the less odorous oil with caproic acid (hexanoic acid), cinnamic acid and isobutyric acid gave rise to highly fragrant products. Such aroma materials could become commercially valuable for their long-lasting stable notes; they could find extensive use in floral fragrances, essences and perfume blends.