Sample preparation of Hedyotis diffusa Willd. for two-dimensional gas chromatography-time of flight mass spectroscopic analysis enhanced chemical profiling

Hedyotis diffusa Willd., a herbal remedy for cancer, has a complex chemical profile that is difficult to analyze in detail. Here, we introduce an optimized sample preparation method coupled with two-dimensional gas chromatography-time-of-flight mass spectrometry (GC ​× ​GC-TOF/MS) to enhance the chemical profiling of H. diffusa. By employing dichloromethane extraction for nonpolar compounds, aqueous extraction, and solid-phase extraction fractionation into moderately polar and polar fractions, we extracted and analyzed a comprehensive range of chemicals from H. diffusa. GC ​× ​GC-TOF/MS analysis revealed a rich chemical landscape, identifying 185, 325, and 483 peaks in the dichloromethane extract, solid-phase extraction elution, and unretained fractions, respectively. Library matching against known compounds confirmed 155, 178, and 184 hits with a similarity of 80% or greater. Notably, this method also involves group-type elution of steroids and anthraquinones, facilitating the identification and screening of similar compounds. This comprehensive approach to herbal chemical analysis offers a high-dimensional perspective and greatly advances our understanding of the chemical constituents of H. diffusa.