Identification of Octyl Gallate, a Novel Apoptosis-inducing Compound for Colon Cancer Therapy, from Sanguisorba Officinalis L. by Cell Membrane Chromatography and UHPLC-(Q)TOF-MS/MS

Colon cancer is a common gastrointestinal malignancy that ranks third in incidence among gastrointestinal cancers. Therefore, screening bioactive compounds for treatment of colon cancer is urgently needed. Sanguisorba officinalis L. (SO) has been demonstrated that the extractions or monomers possess potential anti-tumor effect. In this study, we firstly used cell membrane chromatography (CMC) and ultra-performance liquid chromatography coupled with (quadrupole) time-of-flight mass spectrometry(UHPLC-(Q) TOF-MS/MS) to identify a novel active ingredient, octyl gallate (OG), from SO methanol extract (SO-MtOH). HCT116 and SW620 cells lines were used for in vitro research, which showed OG presents great anti-colon cancer effect by inhibiting proliferation, inducing apoptosis, and repressing the migration and invasion. Furthermore, SW620 bearing athymic nude mice was used to investigate the potential antitumor activity in vivo, which exhibited OG treatment remarkably lessened the tumor volume. Mechanism studies showed that OG downregulated the PI3K/AKT/mTOR signaling axis and induced apoptosis by upregulating the Bax/Bcl-2 protein and the cleaved caspase-3, caspase-9. In conclusion, our research innovatively applied the method of CMC to intriguingly unearth the potential anti-colon cancer ingredient OG and demonstrated its the great antineoplastic activity, which provide a new insight for researchers efficiently developing the novel apoptosis-inducing compound for colon cancer therapy.