CHROMATOGRAPHIC DETECTION AND SPECTROPHOTOMETRIC DETERMINATION OF DIOSGENIN AND OTHER Δ⁵–SAPOGENINS IN CRUDE PLANT EXTRACTS

Abstract

When ?^5– sapogenin, such as diosgenin, was shaken with a 25 % solution of antimony trichloride in 60 % perchloric acid, a pink colour („kmax 500 nm) which obeyed Beer's Law was produced, at room temperature. The accurate determination of diosgenin in the presence of either phytosterol or a limited amount of fixed oil was achieved by the addition of a small amount of a mixture of chloroform and absolute ethanol, 1:1. The relative standard deviation was 3 % on 50 μg of pure diosgenin and 6 % on a crude extract (of Dioscorea deltoidea tuber) containing the equivalent of 50 μg of diosgenin. The procedure gives the ?^5– sapogenin content calculated as diosgenin. Detection of other ?^5– sapogenins is effected by TLC of the crude extract.