Sesame (Sesamum indicum L.) leaves (SLs) are used as vegetables and traditional medicines in Asian and African countries. We investigated in vitro antioxidant and anti-colon cancer efficacy of ethanol extract of SL (SLE) and its major bioactive component. SLE contained appreciable amount of major classes of antioxidant phytochemicals, such as total polyphenols, total flavonoids, and carotenoids, and correspondingly exhibited antioxidant activities, such as radical scavenging activity and ferric reducing antioxidant power (FRAP). A cell viability assay showed that SLE time- and dose-dependently attenuated the growth of human colon cancer cells, HT29 and HCT116. Flow cytometry analysis showed that SLE increased sub-G1 (in HT29 and HCT116) and G2/M (in HCT116) cell populations, suggesting that the growth inhibition by SLE was due to induction of apoptosis and G2/M cell cycle arrest. Trans-well and wound-healing assays showed that SLE alleviated invasion and migration of HT29 and HCT116 cells in non-cytotoxic conditions. High-performance liquid chromatography analysis revealed that pedaliin (6-hydroxylueolin 7-methyl ether 6-glucoside; pedalitin-6-O-glucoside) was a major constituent of SLE. Moreover, FRAP, growth-inhibitory, anti-invasive, and anti-migratory activities of pedaliin were found. These results demonstrated that SLE possesses in vitro antioxidant and anti-colon cancer activities and that pedaliin is a major component contributing to such activities.

Colorectal cancer is one of the most common cancers in both incidence and mortality among men and women worldwide. Sesame (Sesamum indicum L.) leaves (SL) are used as vegetables and traditional medicines in Asian and African countries. In the current study, we aimed to investigate the effects of ethanol extract of sesame leaves (SLE) against key characteristics of cancer cells, including unrestricted growth, resisted apoptosis, and activated metastasis, and to evaluate whether thermal treatment of SL alter the inhibitory effects. Two human colon cancer cell lines were used in this study, HT29 colon adenocarcinoma cells and HCT116 colorectal carcinoma cells. In 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, treatment with SLE at the concentrations of 50-500 µg/mL for 24-72h resulted in dose-dependent and time-dependent growth inhibition in HT29 and HCT116 cells. In cell cycle analyses, SLE caused significantly increased cell population at sub-G1 (in HT29 and HCT116) and G2/M (in HCT116) phases, suggesting that the observed growth inhibition is associated with induction of apoptosis and cell cycle arrest. SLE at non-cytotoxic concentrations was effective in inhibiting critical events during metastasis in HT29 and HCT116, such as invasion (determined by matrigel-coated transwell assay), migration (determined by wound-healing assay), and adhesion (determined using fibronectin-coated plates). Thermal treatment of SL (at 150°C for 15 min) resulted in significantly enhanced inhibitory activities of SLE against the invasion, migration and adhesion in HCT116 cells, but did not change the growth-inhibitory and apoptosis-inducing activities. These results suggest that SLE possesses in vitro anti-cancer activities against colon cancers and that thermal treatment of SL enhances the anti-metastatic activities of SLE. Further studies are needed to verify whether similar effects are reproduced in vivo and to identify active ingredients of SLE responsible for the inhibitory activities. Citation Format: Seoyun Kim, Jihyeung Ju. Inhibitory activities of Sesamum indicum L. leaf extract against the growth, invasion, migration, and adhesion of human colon cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr LB-168.