Rapid screening and identification of the differences between metabolites of Cistanche deserticola and C. tubulosa water extract in rats by UPLC-Q-TOF-MS combined pattern recognition analysis.

Cistanches Herba is a famous traditional Chinese medicine that has been in use for treating kidney deficiency, impotence, female infertility, morbid leucorrhea, profuse metrorrhagia, and senile constipation. With the exception of studies available for a few single active ingredients such as echinacoside, acteoside, and poliumoside, comprehensive and systematic studies on in vivo metabolism of Cistanches Herba are lacking despite its widespread clinical application. There is no comparative study yet on the metabolites resulting from the traditional usage of Cistanche deserticola and C. tubulosa water extract - two species that are recorded in Chinese Pharmacopoeia. This further restricts research on the therapeutic effect of Cistanches Herba to a great extent. In this study, a robust and unbiased UPLC-Q-TOF-MS combined pattern recognition analysis (orthogonal partial least squared discriminant analysis, OPLS-DA) was employed to rapidly screen prototype components and metabolites of C. deserticola and C. tubulosa water extract in rat urine, feces, and serum. A total of 71 metabolites from C. deserticola including 25 prototype components and 46 metabolites, and 45 metabolites from C. tubulosa including 18 prototype components and 27 metabolites were tentatively identified. Out of these, 10 metabolites were characterized for the first time in these two species. Results of this study indicate that phenylethanoid glycosides (PhGs) are mainly metabolized into degradation products in the gastrointestinal tract of rats. The chemical components cistanoside B, C, D, and E exist only in C. deserticola and release methylated hydroxytyrosol (HT) following metabolism. This factor contributes to the difference between metabolites of C. deserticola and C. tubulosa water extract in rats and is responsible for the differential therapeutic effect that these two species of Cistanches Herba have on the same diseases.