Molecular Docking of Volatile Oily Constituents of Chinese Herbal Medicine Asari Radix et Rhizoma and CYP1A2 Enzyme / 中国实验方剂学杂志

Objective::To study the mechanisms of action of four volatile oil components (safrole, myristicin, methyleugenol and asarone) and the reactive metabolites of safrole and myristicin with CYP1A2. Method::The inhibitory effects of the volatile oil components of Asari Radix et Rhizoma on the human liver microsomal enzymes CYP1A2, CYP2D6, CYP2E1, CYP3A4 and CYP2C19 were screened by the " Cocktail" probe substrate method. The ability of the volatile oil components and intermediates in binding to CYP1A2 enzyme was studied by means of semi-flexible molecular docking. Result::The screening results showed that the components had a strong inhibitory effect on CYP1A2.Molecular docking scores were 3.048 7 kcal·mol-1 (safrole), 6.016 4 kcal·mol-1 (myristicin), 16.969 2 kcal·mol-1 (methyleugenol), 16.013 8 kcal·mol-1 (asarone), 23.923 3 kcal·mol-1 (safrole reactive metabolites) and 25.594 3 kcal·mol-1 (myristicin reactive metabolites). Conclusion::Molecular docking results indicate that safrole metabolic intermediate and myristicin metabolic intermediate have the strongest ability in binding to CYP1A2 enzyme. This study further confirms that safrole and myristicin are the mechanism-based inhibitors of CYP1A2 enzyme, which is consistent with the results of previous IC50-shift and glutathione capture experiments.

An important mechanism of herb-induced hepatotoxicity: To produce RMs based on active functional groups-containing ingredients from phytomedicine by binding CYP450s / 中草药·英文版

Reactive metabolites (RMs) generated by hepatic metabolism are thought to play an important role in the pathogenesis of drug-induced liver injury (DILI). Like many synthetic drugs undergoing metabolic activation to form RMs which are often associated with drug toxicity, it is recognized that some herbal components may be also converted to toxic, or even mutagenetic and carcinogenic metabolites by cytochrome P450s (CYP450s). This review focuses on the metabolic activation of herbal components and its liver toxicological implications. By summarizing references, we found that hepatotoxic herbal components via producing RMs have some certain structural dependence. There is a correlation between the generation of RMs and the structures, which provides a good chance for the early discovery of toxic ingredients in Traditional Chinese medicines (TCMs): i) A potential hepatotoxic component information database based on active functional groups can be built, which might provide an early information for the basic research of hepatotoxic substances in TCMs; ii) RMs can combine with CYP450s to form a complete antigen, which eventually leads to an antigen-specific immune response. RMs-CYP450 protein complete antigen can be set up, and the potential idiosyncratic liver toxicity might be predicted by testing RMs-CYP450 protein antibody in plasma.

A Review of Formation, Toxicity of Reactive Oxygen Species by Heavy Metals and Tolerance in Plants

Aims: This whole review tells about origin of ROS, Cell death, role of ROS, defense system in numerous developmental pathways.Methodology: In plant reactive oxygen species are the main factor of cell mechanism deterioration. The stability of the reduction and regeneration is disturbed under stress environment. ROS continuously damages the main organelles of cell in plants as well as inactivate several enzymes. Break down of lipids, nucleic acid, proteins, pigments, damages in membrane which may lead to cell death.Conclusion: ROS is diffusible measures in pathways of signal transduction in numerous developmental pathways in plants. ROS acts as a messenger. Plants protect cell from misbalancing and also damages ROS production. ROS produced in excess amount rather than required for numerous metabolic reaction. In aerobic respiration ROS is produced

Reactive metabolites and antioxidant gene polymorphisms in type 2 diabetes mellitus.

Type 2 diabetes mellitus (T2DM), by definition is a heterogeneous, multifactorial, polygenic syndrome which results from insulin receptor (IR) dysfunction. It is an outcome of oxidative stress caused by interactions of reactive metabolites (RMs) with lipids, proteins and other molecules of the human body. Production of RMs mainly superoxides (•O2 −) has been found in a variety of predominating cellular enzyme systems including nicotinamide adenine dinucleotide phosphate oxidase, xanthine oxidase, cyclooxygenase, endothelial nitric oxide synthase (eNOS) and myeloperoxidase. The four main RM related molecular mechanisms are: increased polyol pathway flux; increased advanced glycation end‑product formation; activation of protein kinase C isoforms and increased hexosamine pathway flux which have been implicated in glucose‑mediated vascular damage. Superoxide dismutase, catalase, glutathione peroxidase, glutathione‑S‑transferase and NOS are antioxidant enzymes involved in scavenging RMs in normal individuals. Functional polymorphisms of these antioxidant enzymes have been reported to be involved in the pathogenesis of T2DM. The low levels of antioxidant enzymes or their non‑functionality results in excessive RMs which initiates stress related pathways thereby leading to IR and T2DM. An attempt has been made to review the role of RMs and antioxidant enzymes in oxidative stress resulting in T2DM.