Neolignan derivatives from Penthorum chinense with antitumor activity in human colorectal cancer cells by regulating Wnt/β-catenin signaling pathway

In vitro cytotoxicity-guided isolation based on a MTT assay was conducted for Penthorum chinense Pursh. (Penthoraceae). In the active components (EtOAc extract of P. chinense), eight undescribed neolignans, penthoneolignans A–H (1–8), and two known analogs (9 and 10) were obtained and identified. Their absolute configurations were determined by experimental and computational comparison of electronic circular dichroism spectra analysis. The MTT experiment results of the obtained neolignans on HT29 and LoVo cells indicated previously undescribed neolignans, penthoneolignans A (1) and F (6), showed better cytotoxicity than the positive drug 5-fluorouracil. Then, functional technologies such as the 5-ethyny1-2′-deoxyridine, wound healing, Transwell, and Western blot assays indicated that they could significantly inhibit the proliferation of HT29 and Lovo cells, promote apoptosis by up-regulating Bax, and down-regulating B-cell CLL/lymphoma 2 and poly ADP-ribose polymerase. Furthermore, a Western blot assay combining the Dsh homolog 2 agonist IWP-L6 and the β-catenin agonist MG132 suggested their mechanism of action was closely related to the inhibition of the Wnt/β-catenin signaling pathway. In conclusion, previously undescribed neolignans, penthoneolignans A (1) and F (6), may intervene in the development and progression of colorectal cancer by inhibiting the Wnt/β-catenin signaling pathway and have the potential to be drug candidates.