In Vitro Anticancer Effects of a Traditional Sri Lankan Polyherbal Decoction and Its Individual Components Against Colorectal Cancer Cells

Background Colorectal cancer is globally the third highest prevalent and second highest mortality malignancy. Modern treatments were failed to reduce the cancer deaths to the expected level via producing exceptional side effects. On the contrary, traditional herbal medicine is gaining more attention in cancer remedies mainly due to its high efficacy and fewer side effects. The current study was aimed at investigating the anticancer and antioxidant properties of a poly-herbal decoction prescribed in Sri Lankan traditional cancer treatments. A polyherbal decoction (PHD) prepared using the Adenanthera pavonina , Thespesia populnea , Tinospora cordifolia , and Withania somnifera , and decoctions prepared from these four individual plants were used commonly in Sri Lankan traditional medicine for colorectal cancer treatments. Methods investigated for their total polyphenolic content, anti-oxidant activity, in vitro anti-colon cancer and apoptosis inducing activity (in HCT116 cell line) using 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, Ferric Reducing Antioxidant Power (FRAP) assay, hydroxyl radical scavenging assay, 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay, caspase activity assay and Real-time quantitative Polymerase Chain Reaction (RT-qPCR) respectively. Results Out of the five decoctions, W. somnifera decoction (WSD) exhibited strong anti-colon cancer activity (EC₅₀ = 83.1 ± 1.1 µg/mL) while PHD and other decoctions exhibited limited anti-cancer activity (EC₅₀ >100 µg/mL). WSD suppressed colony formation and induced caspase dependent programmed cell death, and lactate dehydrogenase (LDH) leakage. Up regulation of tumor suppressor p53 gene expression and down regulation of expression of key oncogenic and anti-apoptotic genes MMP-2, MMP-9, STAT3, JAK2, Cyclin D1, VEGF, and Bcl-XL were observed. Conclusions Overall findings validates the traditional use of Poly Herbal Decoction and W. somnifera decoction against colon cancer.