Improved Chiral Separation of (R,S)-Goitrin by SFC: An Application in Traditional Chinese Medicine

Abstract

Like chemical drugs, research and development of herbal medicine also have a need to resolve enantiomers. To help illustrating the antiviral bioactivity of Isatidis Radix, a widely used traditional Chinese medicine (TCM), supercritical fluid chromatography (SFC) was used for analytical and preparative separation of (R,S)-goitrin, which was reported as the active ingredient of the herbal. Improved resolution was achieved on Chiralpak IC column, using acetonitrile as the organic modifier, representing a tenfold increase in speed, compared to the previous normal phase HPLC (NPLC) method. The newly developed chromatographic method was validated in terms of linearity, precision, limit of detection (LOD), and limit of quantitation (LOQ). Scale-up purification of (R)-goitrin and (S)-goitrin was performed on a preparative column with >90% total recovery. The absolute stereochemical assignment of the purified isomers was determined through optical rotation study. This attempt explored SFC's application in chiral research of traditional Chinese medicine.

Stereospecific Assay of (R)- and (S)-Goitrin in Commercial Formulation of Radix Isatidis by Reversed Phase High-Performance Liquid Chromatography

“…The migration order of the enantiomers is the same as that from the reported SFC method but is the opposite to that from the NPLC method [29, 30]. …”

“…(R, S)-Goitrin reference (product number 111753) was obtained from National Institutions for Food and Drug Control (Beijing, China) with content of 100%. (R)-Goitrin and (S)-goitrin were previously prepared by the SFC method [30]. All the experiments used purified water from a Direct-Q 3 system (Millipore, Bedford, USA).…”

“…Later, we developed an SFC methodology for the fast and high-throughput separation and preparation of (R)- and (S)-goitrin [30]. However, the above two protocols are based on the normal phase chromatographic system, which uses low-polarity solvents such as n -hexane and CO 2 as the mobile phase.…”

Antiviral activity of Isatidis Radix derived glucosinolate isomers and their breakdown products against influenza A in vitro/ovo and mechanism of action

“…Epigoitrin and goitrin were separated from (R, S)-goitrin reference standard (National Institutes for Food and Drug Control, Lot No. 111753-201706) by SFC chiral resolution on a Chiralpak IC column with acetonitrile and carbon dioxide as the mobile phase (Nie et al, 2016). The structures of the purified compound were confirmed by 1 H and 13 C NMR (Bruker DRX-500), MS (Waters SYNAPT G2) and optical rotation (Rudolph Autopol IV).…”

“…In addition, (R, S)-goitrin was first resolved by the authors (Nie et al, 2010) using normal phase liquid chromatography (NPLC). Later, novel supercritical fluid chromatography (SFC) and high performance liquid chromatography (HPLC) methods were developed for high-throughput chiral separation and stereospecific assay, respectively (Nie et al, 2016(Nie et al, , 2017. On the other hand, epigoitrin and goitrin were verified as breakdown products of their glucosinolate prototypes, epiprogoitrin ((R)-hydroxy-3-butenylglucosinolate) and progoitrin ((S)-hydroxy-3-butenylglucosinolate), on the effect of myrosinase ( Fig.…”