ROS, RNS, and carcinogenic metabolites generate excessive oxidative stress, which changes the basal cellular status and leads to epigenetic modification, genomic instability, and initiation of cancer. Epigenetic modification may inhibit tumor-suppressor genes and activate oncogenes, enabling cells to have cancer promoting properties. The nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor that in humans is encoded by the NFE2L2 gene, and is activated in response to cellular stress. It can regulate redox homoeostasis by expressing several cytoprotective enzymes, including NADPH quinine oxidoreductase, heme oxygenase-1, UDP-glucuronosyltransferase, glutathione peroxidase, glutathione-S-transferase, etc. There is accumulating evidence supporting the idea that dietary nutraceuticals derived from commonly used fruits, vegetables, and spices have the ability to produce cancer chemopreventive activity by inducing Nrf2-mediated detoxifying enzymes. In this review, we discuss the importance of these nutraceuticals in cancer chemoprevention and summarize the role of dietary terpenoids in this respect. This approach was taken to accumulate the mechanistic function of these terpenoids to develop a comprehensive understanding of their direct and indirect roles in modulating the Keap1-Nrf2-ARE signaling system.

Background: Operculina turpethum (OT) is widely known for its use in traditional treatment practices to heal several diseases, such as bronchitis, pectoralgia, arthralgia, diarrhea, obesity, helminthiasis, gastropathy, ascites, sporadic fever, leucoderma, inflammation, pruritis, ulcers, erysipelas, tumors, jaundice, hemorrhoids, ophthalmia, etc. In this report, the antidiarrheal potential of the O. turpethum (EEOT) stem was assessed in an animal model along with a molecular docking study of previously isolated compounds to determine the mechanism involved in identifying prospective phytocompounds against diarrhea. Methods: Ethanolic stem extract was used in a mouse model of castor oil-induced in vivo antidiarrheal syndrome. In silico molecular docking analysis was performed using the ‘Vina Wizard’ program in PyRx – Python Prescription 0.8. Results: At 250 and 500 mg/kg, the EEOT stem dose-dependently demonstrated significant differences in antidiarrheal potential. During molecular docking analysis, out of four previously isolated compounds from O. turpethum stem, three (22,23-dihydro-α-spinosterol-ß-D-glucoside, 3-(4-hydroxy-phenyl)-N-[2-(4-hydroxy phenyl)-ethyl]-acrylamide and β-sitosterol-β-D-glucoside) have shown satisfactory binding affinity against the target M3 muscarinic acetylcholine receptor compared with the reference standard drug loperamide. Conclusion: The EEOT stem has significant potential to prevent diarrhea, which can be rationalized by molecular docking analysis, in which secondary plant metabolites were found to bind promisingly to their target receptor.

Operculina turpethum is widely known for its use in traditional treatment practices to heal several diseases, such as bronchitis, pectoralgia, arthralgia, diarrhea, obesity, helminthiasis, gastropathy, ascites, sporadic fever, leucoderma, inflammation, pruritis, ulcers, erysipelas, tumors, jaundice, hemorrhoids, and ophthalmia. In this study, the antidiarrheal potential of the ethanolic extract of O. turpethum stem was assessed in an animal model, and molecular docking of previously reported stem-derived compounds was performed to determine the possible mechanism of action. The in vivo antidiarrheal effect was assessed using a castor oil-induced mouse model. In silico molecular docking analysis was performed using the ‘Vina Wizard’ program in PyRx 0.8. The stem extracts at 250 and 500 mg/kg produced significant, dose-dependent antidiarrheal activity. Among the four previously isolated compounds, three (22,23-dihydro-α-spinosterol-ß-D-glucoside, paprazine, and sitogluside) showed satisfactory binding affinity against the target M3 muscarinic acetylcholine receptor, comparable to the reference standard drug loperamide. These findings suggest that the O. turpethum stem has significant potential to prevent diarrhea that warrants further phytochemical, pharmacological, and mechanistic investigations.