Bioassay-Guided Isolation and HPLC Quantification of Antiproliferative Metabolites from Stahlianthus thorelii

In folk medicine, Stahlianthus thorelii Gagnep. has been used to treat diseases related to inflammation, ulcers, and cancer. There are no reports concerning the chemical components and bioactivities of S. thorelii; thus, this study aims to explore the phytochemicals, quantify the main compounds, and test the anticancer activity of isolates from S. thorelii. Dried rhizomes were extracted with 95% ethanol and, then, partitioned, fractionated, and isolated. On the basis of the result of the antiproliferative activity of the fractions, seven isolates were yielded and were identified by spectroscopic analyses. The inhibition of cancer proliferation was determined by an MTT assay and the deployed IC(50) to value their efficacy. Seven compounds containing one new C-benzylated dihydrochalcone derivative, thorechalcone A (1) and 2–7 were isolated from S. thorelii. In terms of the bioactivity, compounds 1 and 3 displayed promising antiproliferative activity (WiDr, A549, and HepG2), with IC(50) values <40 µM. The HPLC-UV method of quantification of two major compounds (3 and 4) was also validated. This study presented the isolations of antiproliferative potentials of new chalcone and known flavonoid derivatives from S. thorelii. The validated simple, accurate, and rapid HPLC method could be deployed for the quality control of herbal drugs.