Amelioratory Effect of Nanoconjugated Vancomycin on Spleen during VRSA-Induced Oxidative Stress

A review on oxidant and antioxidant effects of antibacterial agents: impacts on bacterial cell death and division and therapeutic effects or adverse reactions in humans

Reactive oxygen species (ROS) are produced in the mitochondrial respiratory pathway and cellular metabolism. They are responsible for creating oxidative stress and lipid peroxidation. In living organisms, there is a balance between oxidative stress and the antioxidant system, but some factors such as medicines disturb the balance and cause many problems. These effects can impact bacterial death and division and also in humans can induce therapeutic or adverse reactions. Web of Science and Pubmed databases were used for searching. This review focuses on the oxidant and antioxidant effects of different classes of antibacterial agents and the mechanisms of oxidative stress. Some of these agents have beneficial effects on killing bacteria due to their antioxidant or oxidant effects. However, some of their side effects may be due to their oxidative effects. Based on the results of this review, minocycline is an antioxidant, but aminoglycosides, chloramphenicol, glycopeptides, antituberculosis drugs, fluoroquinolones, and sulfamethoxazole agents have oxidant effects. Furthermore, cephalosporins, penicillins, metronidazole, and macrolides have both oxidant and antioxidant effects in different studies. It is concluded that some antibacterial agents have oxidant and other antioxidant effects. These activities may affect their therapeutic effects or side effects. Some antioxidants can prevent the adverse effects of antibacterial agents. Clarifying the exact oxidant and antioxidant effects of some antimicrobial agents needs more research projects.

Anti-inflammatory and antioxidant effect of methanol extract of latex of Calotropis procera in rat model of colorectal cancer

ETHNOPHARMACOLOGICAL RELEVANCE

Preparations derived from the plant Calotropis procera, have been used for medicinal purpose though the plant is known for its toxic effects. The aerial parts of the plant contain latex in plenty and have been found effective in treating disorders of gastrointestinal system and cancer.

AIM OF THE STUDY

This study evaluated the efficacy of C. procera dried latex extract prepared in methanol (MeDL) against inflammation and oxidative stress in experimental model of colorectal carcinoma (CRC).

MATERIALS AND METHODS

Two subcutaneous injections of chemical carcinogen, 1,2-dimethylhydrazine (DMH; 150 mg/kg) were given at an interval of one week to induce CRC in rats. The MeDL (50 and 150 mg/kg) and aspirin (60 mg/kg) were given daily and their effect was evaluated on markers of oxidative stress and inflammation after completion of 8 weeks following second injection of carcinogen. A comparison was made with normal and experimental control groups. The colon tissue levels of glutathione (GSH), thiobarbituric acid reactive substances (TBARS), superoxide dismutase (SOD), nitrite and myeloperoxidase (MPO) were determined. Enzyme-linked immunosorbent assay was performed to determine the levels of prostaglandin E₂ (PGE₂) and tumor necrosis factor-alpha (TNF-α) and immunohistochemical analysis was performed for IL-1β.

RESULTS

Induction of cancerous changes in the colon resulted in altered oxidative homeostasis as evident from a reduction in GSH level and SOD activity and rise in TBARS level when compared with normal rats. Elevated levels of nitrite, MPO, TNF-α, PGE₂ and immunoreactivity of IL-1β were also observed in these rats. The levels of these markers were normalized when the rats were treated with MeDL or anti-inflammatory drug, aspirin.

CONCLUSION

This study demonstrates that suppression of oxidative stress and inflammation contributes to the beneficial effect of MeDL in rat model of colon carcinogenesis.

Dichlorophene activates aryl hydrocarbon receptor (AhR) and indoleamine 2, 3-dioxygenase 1 (IDO1) to mediate splenotoxicity in rat

Dichlorophene (DCP) is a halogenated phenolic compound, widely used as fungicide, bactericide and antiprotozoan and also exhibit therapeutic application in several pathological conditions. Taking account of broad use of DCP, its possible effect on spleen (an important immune organ) was investigated in this study. Male albino rats were treated with graded doses of DCP (10%, 20% and 30% of LD50) and spleen and blood were obtained at 24, 48 and 72 hours post treatment. Oxidative stress parameters, proinflammatory cytokines and protein expression of aryl hydrocarbon receptor (AhR), indoleamine-2, 3-Dioxygenase 1 (IDO1) and nuclear factor erythroid 2-related factor 2 (Nrf2) were measured along with histopathological evaluation of spleen. In the present study, DCP perturbs redox status of splenocytes of rats as evidenced by excess ROS generation, lipid peroxidation and nitric oxide production simultaneously with reduction of antioxidant level [glutathione (GSH)] and inhibition of antioxidative enzymes [superoxide dismutase (SOD) and catalase (CAT)]. Two important proinflammatory cytokines, IL-6 and TNF-α were found to be elevated upon DCP treatment. Moreover, DCP also caused activation of AhR and IDO1 with simultaneous down regulation of Nrf2. All these effects of DCP were found to be dose and duration dependent. DCP also affects the spleen micro-architecture in the present study and these alterations were more prominent in high dose group at 72 hours post treatment. Taken together, all these results suggested that DCP induces oxidative stress and also increases proinflammatory cytokine levels to mount its toxic effect on spleen.

Synthesis, Characterization, In Vitro Anticancer Potentiality, and Antimicrobial Activities of Novel Peptide-Glycyrrhetinic-Acid-Based Derivatives

Glycyrrhetinic acid (GA) is one of many interesting pentacyclic triterpenoids showing significant anticancer activity by triggering apoptosis in tumor cell lines. This study deals with the design and synthesis of new glycyrrhetinic acid (GA)-amino acid peptides and peptide ester derivatives. The structures of the new derivatives were established through various spectral and microanalytical data. The novel compounds were screened for their in vitro cytotoxic activity. The evaluation results showed that the new peptides produced promising cytotoxic activity against the human breast MCF-7 cancer cell line while comparing to doxorubicin. On the other hand, only compounds 3, 5, and 7 produced potent activity against human colon HCT-116 cancer cell line. The human liver cancer (HepG-2) cell line represented a higher sensitivity to peptide 7 (IC50; 3.30 μg/mL), while it appeared insensitive to the rest of the tested peptides. Furthermore, compounds 1, 3, and 5 exhibited a promising safety profile against human normal skin fibroblasts cell line BJ-1. In order to investigate the mode of action, compound 5 was selected as a representative example to study its in vitro effect against the apoptotic parameters and Bax/BCL-2/p53/caspase-7/caspase-3/tubulin, and DNA fragmentation to investigate beta (TUBb). Additionally, all the new analogues were subjected to antimicrobial assay against a panel of Gram-positive and Gram-negative bacteria and the yeast candida Albicans. All the tested GA analogues 1-8 exhibited more antibacterial effect against Micrococcus Luteus than gentamicin, but they exhibited moderate antimicrobial activity against the tested bacterial and yeast strains. Molecular docking studies were also simulated for compound 5 to give better rationalization and put insight to the features of its structure.

Artesunate suppresses inflammation and oxidative stress in a rat model of colorectal cancer

Anti-inflammatory drugs are well known to reduce the risk of colon cancer and prophylactic use of such agents is gaining acceptance as a cancer prevention therapy. As artesunate, an antimalarial drug, has been shown to exhibit chemopreventive properties, the present study was carried out to evaluate its inhibitory effect on oxidative stress and inflammation in a rat model of colon carcinogenesis. A chemical carcinogen, 1,2-dimethylhydrazine was injected twice at an interval of 1 week to induce preneoplastic lesions in the colon and the parameters indicating oxidative stress and inflammation were evaluated after 8 weeks. Artesunate (50 and 150 mg/kg) and aspirin (60 mg/kg) were administered orally throughout the study. Analysis of colon tissue revealed that both the drugs preserved histoarchitecture, inhibited cellular influx, decreased the levels of oxidative stress and inflammatory markers, downregulated cyclooxygenase-2, inducible nitric oxide synthase, nuclear factor κB, and interleukin 1β in comparison to the experimental control. Suppression of oxidative stress and pro-inflammatory signaling by both the drugs were found to contribute to inhibition of colon carcinogenesis. The protection afforded by these drugs was found to be comparable. Our study shows that like aspirin, use of artesunate could also reduce the risk of colon cancer and it has a potential for further evaluation for the treatment purpose.

Protection afforded by methanol extract of Calotropis procera latex in experimental model of colitis is mediated through inhibition of oxidative stress and pro-inflammatory signaling

Calotropis procera, a latex producing plant is known to possess medicinal properties including its beneficial effect in gastrointestinal disorders. The anti-inflammatory effect of its latex in various experimental models is noteworthy and in light of this the present study was carried out with an objective to evaluate its efficacy in ulcerative colitis, an inflammatory condition of the colon. Colitis was induced in rats by acetic acid and the rats were divided into four groups where one group served as experimental control and the other groups were treated with two doses of methanol extract of dried latex of C. procera (MeDL; 50 and 150 mg/kg) and mesalazine (MSZ; 300 mg/kg). The study also included normal control (NC) group for comparison of various parameters related to colon like macroscopic changes, ulcer score, adherent mucus content, weight/length ratio, small intestinal transit, oxidative stress and inflammatory markers, tissue histology and immunoreactivity of cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS) and nuclear factor kappa beta (NFκB) subunit p65. Treatment of colitic rats with MeDL produced a significant reduction in colonic mucosal damage as revealed by macroscopic and microscopic evaluation and normalization of tissue levels of oxidative stress markers and pro-inflammatory mediators. The protection afforded by MeDL was also evident from its restorative effect on tissue histology and expression of COX-2, iNOS and NFκB(p65). This study shows that by targeting oxidative stress and NFκB(p65) mediated pro-inflammatory signaling, the latex of C. procera affords protection in colitis and its effect was comparable to that of mesalazine. This study suggests that latex of C. procera could serve as a promising therapeutic option for treating inflammatory conditions of the colon.