In-vitro Study of Macelignan as a Potential Anticancer Drug against Colorectal Cancer using HCT116 Cell Line

Introduction: Many recent studies have shown that lignans from many plant sources have an effective impact on cancer treatment and it is evident that many medicinal plants are rich in lignans. Genus Leucas is known for its medicinal use and is rich in lignans. Macelignan a polyphenolic derivative might play significant roles as clinically useful anticancer agents in treating Colorectal Cancer (CRC).

Aim: Isolation, characterisation and pharmacological profiling of bioactive compound lignan from Leucas aspera and Leucas cephalotes and to assess the anticancer potential using in-vitro methods using Human Colorectal Cancer (HCT116) cell lines.

Materials and Methods: This in-vitro study was conducted from August 2018 to January 2020 at The Oxford College of Engineering in Bengaluru, Karnataka, India. Anticancer potential of Macelignan was evaluated through 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, Reactive Oxygen Species (ROS) measurement, cell cycle study, apoptosis analysis, and gene expression studies. One-way Analysis of Variance (ANOVA) was performed for the total phenolic content estimation and the results were expressed as mean±SD with n=3 trials.

Results: The MTT assay result indicated that macelignan has an IC50 value of 22.8 μM with 73% of cells showing inhibition, ROS production was enhanced 2.5-fold at a maximum concentration at 100 μM. Macelignan (12.5 μM and 25 μM) significantly prevented cell growth in G0/G1 and G2 phases of the cell cycle, while the apoptotic study showed that 12.5 μM and 25 μM macelignan induced early and late apoptosis in HCT116 cells with 21.28% and 19.17%, 21.54 % and 29.02% apoptosis at cellular level, respectively. This set of tests sought to examine the effect of macelignan on the Caspase 3 gene expression in HCT116 cells by semi-quantitative Polymerase Chain Reaction (PCR). The study showed that Caspase 3 expression was upregulated up to 1.98 and 2.87 folds when treated with macelignan.

Conclusion: The macelignan could serve as a potent drug derivative for the treatment of colon cancer with further study on the mechanism of action, structure-activity relation, toxicity profiling, bioavailability.