Evaluation of antimitotic activity of herbal extracts using plant-based model systems and their cytotoxic potential against human colon carcinoma cells.

OBJECTIVE: The aim of this study was to screen plant extracts for antimitotic activity using Vigna radiata germination inhibition assay, followed by Allium cepa root tip assay and evaluation of their cytotoxic potential on colon carcinoma (HCT-116) cell lines. SUBJECTS AND METHODS: Aqueous extracts of Aconitum heterophyllum, Terminalia bellirica, Bauhinia variegata, Vanda roxburghii, and Cassia angustifolia were prepared by maceration method, and preliminary screening studies to check their antimitotic activity were done by V. radiata germination inhibition assay, followed by A. cepa root tip assay. Furthermore, cytotoxic actions were evaluated by cell proliferation assay. Effect of T. bellirica aqueous extract was analyzed to induce morphological changes, cell death, lactate dehydrogenase release, and cell survival of HCT-116 cells. STATISTICAL ANALYSIS USED: The data represented were analyzed by Student's t-test using SigmaStat 2.0 statistical analysis software. The normality of data was tested by the Shapiro-Wilk test before the Student's t-test. P values *P ≤ 0.05, **P ≤ 0.01, and ***P ≤ 0.001 were considered as statistically significant. RESULTS: All the plant extracts showed promising antimitotic activity. Out of all, T. bellirica was highly effective on HCT-116 cells and promising effect on cell proliferation assay and Annexin-propidium iodide staining revealed that T. bellirica efficiently induces apoptosis. CONCLUSIONS: T. bellirica inhibits cancer cell growth and induces apoptotic cell death. Collectively, it may hold potential for cancer therapeutics.

Structural insights into pharmacophore-assisted in silico identification of protein-protein interaction inhibitors for inhibition of human toll-like receptor 4 - myeloid differentiation factor-2 (hTLR4-MD-2) complex.

Toll-like receptor 4 (TLR4) is a member of Toll-Like Receptors (TLRs) family that serves as a receptor for bacterial lipopolysaccharide (LPS). TLR4 alone cannot recognize LPS without aid of co-receptor myeloid differentiation factor-2 (MD-2). Binding of LPS with TLR4 forms a LPS-TLR4-MD-2 complex and directs downstream signaling for activation of immune response, inflammation and NF-κB activation. Activation of TLR4 signaling is associated with various pathophysiological consequences. Therefore, targeting protein-protein interaction (PPI) in TLR4-MD-2 complex formation could be an attractive therapeutic approach for targeting inflammatory disorders. The aim of present study was directed to identify small molecule PPI inhibitors (SMPPIIs) using pharmacophore mapping-based approach of computational drug discovery. Here, we had retrieved the information about the hot spot residues and their pharmacophoric features at both primary (TLR4-MD-2) and dimerization (MD-2-TLR4*) protein-protein interaction interfaces in TLR4-MD-2 homo-dimer complex using in silico methods. Promising candidates were identified after virtual screening, which may restrict TLR4-MD-2 protein-protein interaction. In silico off-target profiling over the virtually screened compounds revealed other possible molecular targets. Two of the virtually screened compounds (C11 and C15) were predicted to have an inhibitory concentration in µM range after HYDE assessment. Molecular dynamics simulation study performed for these two compounds in complex with target protein confirms the stability of the complex. After virtual high throughput screening we found selective hTLR4-MD-2 inhibitors, which may have therapeutic potential to target chronic inflammatory diseases.