THE DETERMINATION OF CURCUMOL IN THE VOLATILE OIL OF CURCUMA AROMATICA BY PHLOROGLUCINOL SPECTROPHOTOMETRY

A method for the determination of curcumol in the volatile oil of Gurcuma aromatica by combined thin-layer chromatography and spectrophotometry was developed. The volatile oil (1:10 MeOH solution) was chromatographed on a silica gel G plate (5.5× 20 cm) with petroleum ether (30～60℃) -acetone-ethyl acetate (94:5:1) as the developing solvent. The curcumol spot was detected by exposing the plate to I₂ vapour for two minutes. After the I₂ had escaped, the spot was scraped into a 10 ml glass-stoppered fugal tube, 1.6 ml 20% phloroglucinol solution (in ethanol.) was then added. The mixture was shaken and allowed to stand for about twenty minutes, concentrated hydrochloric acid was added until the total volume reached 5.0 ml. After centrifugation, the absorbance was measured at 520 nm against a reagent blank. The reaction of phloroglucinol with curcumol is specific, and the method gives steady and reproducible results.