Identification of an Impurity in Commercial Sources of the Tomato Glycoalkaloid Tomatine

Abstract

Abstract Three commercial sources of tomatine showed 2 peaks of approximately equal size when determined by liquid chromatography (LC). Analysis by liquid chromatography/mass spectroscopy (LC/MS) showed one LC peak having an [M + H] ion at 1035, which corresponds to tomatine. The other peak had an [M + H] ion at 1033, which indicates a tomatine-like molecule that has tomatidenol for the aglycone instead of tomatidine or solasodine. Ultraviolet data support a delta C-5–C-6 double bond in the aglycone. LC of tomatine hydrolysate indicated the presence of tomatidine and tomatidenol and the absence of solasodine. Thus, the impurity was dehydrotomatine. Purity calculations based on mass spectral data showed that the tomatine standards were 80% pure.