Spectrophotometric Characterization of Some Authentic Oil of Bergamot and a Few Related Oils

Abstract

Steam distillation separates oil of bergamot into a volatile fraction (85—95% of the original pressed oil) which has a qualitatively significant IR absorption but no appreciable UV absorption in the 270—375 mμ, range. The relatively small steam nonvolatile fraction, however, has significant absorption in the 270—375 mμ range; maximum at 313 mμ, minimum at 277 mμ, and a ratio of 2.45 ± 0.07 for A313/A277. The steam nonvolatile fraction of bergamot consists primarily of the furocoumarin bergaptene. These compounds classed as psoralens have been reported to induce sensitization of the skin under the influence of sunlight or UV irradiation. Initial studies to separate bergamot oil constituents from mixtures have been partially successful. Work on commercial mixtures, and on characterizing the nonvolatile fraction by chemical and physical means, will be continued.

Essential oils and related products

“…Bergamot oil was characterized by the infrared and ultraviolet spectra of its volatile and nonvolatile fractions as described by Rotonclaro (531). The technique also has application for lemon and orange oils.…”

Deterpenation of Citrus Essential Oils by Solvent Partition with Dimethyl Sulfoxide

“…Essential oils are readily extracted from plant tissue by a variety of aliphatic, aromatic, or chlorinated solvents. The terpene hydrocarbons can be separated from oxygenated components by steam distillation (Langenau, 1948;Burchfield and Storrs, 1962;Rotondaro, 1964) or silicic acid chromatography (Kirchner and Miller, 1952). Dimethyl sulfoxide (DMSO) is a polar solvent in which most aromatic and unsaturated hydrocarbons are soluble but in which paraffinic hydrocarbons are only slightly soluble.…”