Changes and mechanisms of terrestroside B and terrestrosin K in stir-frying Tribuli Fructus

Abstract

The contents of terrestroside B and terrestrosin K in Tribuli Fructus with different degree of stir-frying were determined by high performance liquid chromatography with evaporative light-scattering detector( HPLC-ELSD). The results showed that the contents of terrestroside B and terrestrosin K were increased at first and then decreased,and both of them had the highest content at the best time of heating. The results of simulated processing of Tribulus Terrestris saponins showed that when the processing time kept constant,the contents of terrestroside B and terrestrosin K were decreased gradually with the increase of processing temperature from 180 ℃ to240 ℃. At a certain temperature,the content of terrestrosin K was increased first and then decreased with the prolongation of processing time,and reached the highest level at 5 min. However,the content of terrestroside B was increased first and then decreased with the increase of processing time only at 180 ℃,and reached the highest level at 10 min. When the processing temperature was controlled at200,220 and 240 ℃ respectively,the content of terrestroside B was decreased gradually with the increase of processing time. The simulated processing products of tribuluside A,terrestroside B and terrestrosin K were qualitatively characterized by ultra-performance liquid chromatography-time of flight mass spectrometry( UPLC-TOF/MS). It was proved that tribuluside A and terrestrosin Ⅰ containing C-22-OH were dehydroxylated in the processing of Tribuli Fructus and transformed respectively into terrestroside B and terrestrosin K containing C-20-C-22 double bond. As a result,the contents of terrestroside B and terrestrosin K were increased. The sugar chains at C-3 and C-26 positions of terrestroside B and terrestrosin K could be deglycosylated and converted into monosaccharide chain saponins and short sugar chain saponins,so the contents of terrestroside B and terrestrosin K were reduced. The study provides reference for further revealing the processing principle of Tribuli Fructus.