Protective effects of sesame oil on 4-NQO-induced oxidative DNA damage and lipid peroxidation in rats

Effects of sesame (Sesamum indicum L.) and bioactive compounds (sesamin and sesamolin) on inflammation and atherosclerosis: A review

Inflammation, oxidative stress, obesity, infection, hyperlipidemia, hypertension, and diabetes are the main causes of atherosclerosis, which in the long term lead to hardening of the arteries. In the current study, we reviewed recent findings of the mechanism of sesame and its active compounds of sesamin and sesamolin regulates on atherosclerosis. Sesame can decrease the lipid peroxidation and affect the enzymes, which control the balance of oxidative status in the body. Besides modulating the inflammatory cytokines, sesame regulates the main mediators of the signaling pathways in the process of inflammation, such as prostaglandin E2 (PGE2), nuclear factor kappa light-chain enhancer of activated B cells (NF-kB) and peroxisome proliferator-activated receptor gamma (PPAR-γ). Sesame decreases the growth of different pathogens. It fights against obesity and helps to reduce weight, body mass index (BMI), waist circumference, and lipid count of serum and liver. In addition to lowering fasting blood sugar (FBS), it decreases the hemoglobin A1c (HbA1c) and glucose levels and improves insulin function. With high content of linoleic acid, α-linolenic acid, and total polyunsaturated fatty acid (PUFA), sesame efficiently controls the blood plasma lipids and changes the lipid profile. In the case of hypertension, it maintains the health of endothelium through multiple mechanisms and conserves the response of the arteries to vasodilation. PUFA in sesame suppresses blood clotting and fibrinogen activity. All the mentioned properties combat atherosclerosis and hardening of blood vessels, which are detailed in the present review for sesame.

Protective Effect of Thymidine on DNA Damage Induced by Hydrogen Peroxide in Human Hepatocellular Cancer Cells

Intracellular ribonucleotide (RN) and deoxyribonucleotide (dRN) pool sizes are critical for the fidelity of DNA synthesis. They are likely to be severely perturbed by many factors which disrupt the integrity and stability of DNA, leading to DNA damage. Exogenously supplied nucleosides are able to increase the deoxynucleoside triphosphate pools, then reverse the DNA damage, and decrease the oncogene-induced transformation dramatically. In this study, the impact of thymidine on the hydrogen peroxide (H₂O₂)-induced DNA damage was investigated in HepG2 liver cancer cells. From the result of the comet assay, the tail length of cells in the thymidine 600 μM + H₂O₂ 1.0 mM group was dramatically decreased from 42.1 ± 10.8 to 21.9 ± 2.4 μm compared to that exposed with 1.0 mM H₂O₂ (p < 0.05), suggesting that pretreatment of thymidine reduced the DNA damage of HepG2 cells. Although the RN and dRN contents decreased in the damage group, most of them presented increasing tendency when pretreated with thymidine, especially the key metabolites dCTP, which was mainly related with the decline in the rate of DNA synthesis. The restoration also showed a significant G0/G1 phase arrest of cell cycle progression from 44.6 ± 2.2 to 56.6 ± 0.4% after pretreated with thymidine (p < 0.05). In conclusion, our data demonstrated that the pretreatment with thymidine had a potential protective ability against oxidative damage for DNA in HepG2 cells through the perturbation of RN and dRN pools as well as cell cycle arrest, which should provide new insights into the molecular basis of preventing H₂O₂-induced oxidative DNA damage in mammalian cells.

Protective effects of fucoidan against 4-nitroquinolin-1-oxide provoked genetic damage in mouse bone marrow cells

Fucoidan is a unique bioactive and dietary polymer enriched mainly in the cell wall matrix of the brown seaweeds. This present study was intended to reveal the antigenotoxicity effect of fucoidan on 4-nitroquinolin-1-oxide (4-NQO) induced genetics damage and apoptosis in mice bone marrow cells. The 4-NQO caused genetic damages in the form of chromosome/chromatic breakage was estimated by micronuclei assay whereas apoptosis by annexin-V FITC kit and DNA damage by comet assay kit. In addition, oxidative damage in terms of plasma lipid peroxidation (LPO) and 8-OHdG was also estimated. In the experimental regime, six groups with each in five either sex of mice were used. Fucoidan constituted (50,100,200 mg/kg bwt) by orally for 5 days consequently and on 6th day, 4-NQO was administered (7.5 mg/kg bwt) by i.p. The results clearly show that negative control (H2O) and fucoidan alone constituted mice were not exhibited significant effect on LPO, genetic damages whereas positive control group (4-NQO 7.5 mg/kg bwt, i.p.) showed significant effect on genetic damage by showing increased level of LPO (6.25 vs 1.3 μM MDA), 8-OHdG (12 vs 4%), micronuclei about six-fold, 5-fold of comet, and 4-fold of apoptosis when compared with negative control, 11.6 ± 2.07, 5.00 ± 1.58, and 4.14 ± 0.65 respectively. Fucoidan pretreatment significantly protected the 4-NQO-induced genetic damage by 77% decreased level of micronuclei and 96% comet at dose of 200 mg/kg bwt over the positive control whereas LPO, 8-OHdG, and apoptosis were restored as equal to negative control. This study found as fucoidan possessing significant antigenotoxicity property by protecting 4-NQO-induced genetic damage in mice bone marrow cells as dose dependent manner suggest as valuable food supplements and medicine for mankind from environmental toxicants.

Potential application of the oxidative nucleic acid damage biomarkers in detection of diseases

Reactive oxygen species (ROS) are generated after exposure to harmful environmental factors and during normal cellular metabolic processes. The balance of the generating and scavenging of ROS plays a significant role in living cells. The accumulation of ROS will lead to oxidative damage to biomolecules including nucleic acid. Although many types of oxidative nucleic acid damage products have been identified, 8-oxo-7,8-dihydro-2’-deoxyguanosine (8-oxodG) and 8-oxo-7,8-dihydroguanosine (8-oxoG) has been commonly chosen as the biomarkers of oxidative damage to DNA and RNA, respectively. It has been demonstrated that oxidative damage to nucleic acid is an initiator in pathogenesis of numerous diseases. Thus, oxidative nucleic acid damage biomarkers have the potential to be utilized for detection of diseases. Herein, we reviewed the relationship of oxidative nucleic acid damage and development of various diseases including cancers (colorectal cancer, gastrointestinal cancer, breast cancer, lung cancer, epithelial ovarian carcinoma, esophageal squamous cell carcinoma), neurodegenerative disorders and chronic diseases (diabetes and its complications, cardiovascular diseases). The potential of oxidative nucleic acid damage biomarkers for detection of diseases and drug development were described. Moreover, the approaches for detection of these biomarkers were also summarized.

Antioxidants and tumor necrosis factor alpha-inhibiting activity of sesame oil against doxorubicin-induced cardiotoxicity

OBJECTIVE

Oxidative stress is currently considered to be the key factor in doxorubicin-induced cardiotoxicity. Comparatively small quantity of the endogenous antioxidant content of the heart is assumed to be the predisposing factor for doxorubicin-induced cardiotoxicity. The present research was designed to evaluate the antioxidant potential and tumor necrosis factor alpha-(TNF-α) inhibiting activity of sesame oil against acute doxorubicin-induced cardiotoxicity.

METHODS

Male Wistar albino rats (180-200 g) were administered sesame oil in two dissimilar doses (5 and 10 ml/kg body weight, orally) for 30 days, followed by a single dose of doxorubicin (30 mg/kg s.c.).

RESULTS

In the doxorubicin-treated group, increased oxidative stress was proven by a significant rise of thiobarbituric acid reactive substances level and a decrease of myocardial superoxide dismutase, catalase and reduced glutathione content. Histopathological studies showed myocardial necrosis with accumulation of inflammatory cells, vacuolization and overall enlargement of the myocardium. Western blot analysis showed marked expression of TNF-α in the myocardium. Alteration in biochemical parameters by doxorubicin administration was prevented significantly (p < 0.0001) in the 5 and 10 ml/kg sesame oil treated rat hearts. Treatment with 5 and 10 ml/kg of sesame oil reduced the doxorubicin-induced TNF-α expression in the myocardium, which was associated with reduced myocyte injury. The overall effect of sesame oil was comparable with probucol, which shows similar protection.

CONCLUSION

The chronic oral administration of sesame oil prevents acute doxorubicin-induced cardiotoxicity by enhancing cardiac endogenous antioxidants and decreasing myocardial TNF-α expression.

Putative antioxidant property of sesame oil in an oxidative stress model of myocardial injury

BACKGROUND

Sesame oil is a potent antioxidant dietary source for human health. Oxidative stress through generation of free radicals damages the myocardium in different experimental condition. The present research was designed to evaluate the antioxidant property of chronic oral administration of sesame oil against isoproterenol induced myocardial injury.

METHODS AND RESULTS

Male Wistar albino rats were randomly divided into five groups (n = 6) and treated as per treatment protocol with two different doses of sesame oil (5 and 10 ml/kg b.w.) orally for thirty days. At the end of the treatment all the rats (except control rats) were administered with isoproterenol (85 mg/kg) two consecutive days and subjected to biochemical and histopathological estimation. Isoproterenol (group ISO) induced the oxidative myocardial damage via alteration in the endogenous antioxidant enzymes and myocardial marker enzymes. Sesame oil in both the dose (group S1 and S2) shows protective mechanism via decreasing thiobarbituric acid reactive substance (TBARS) and enhancing the endogenous antioxidant enzymes (reduced glutathione (GSH), superoxide dismutase (SOD) and Catalase). Sesame oil also increased the lactate dehydrogenase (LDH), creatine kinase (CK) and aspartate transaminase (AST) as a myocardial marker enzyme in heart homogenate. As histologically evident isoproterenol induced myocardial injury was well preserved by the chronic administration of sesame oil. The protective role of sesame oil was compared with the reference standard α-tocopherol (group S3) also showing the similar effect.

CONCLUSION

From this finding it has been concluded that chronic administration of sesame oil offers cardio protective action via putative antioxidant property.

Antimutagenic and Antiapoptotic Effects of Aqueous Root Extract of Inula racemosa Hook. f. on 4-NQO-Induced Genetic Damage in Mice

The present study was performed as part of an attempt to authenticate the use of Inula racemosa root extract as traditional medicine in India by experimentally investigating their protective effects on 4-nitroquinoline-1-oxide (4-NQO) induced DNA damage and apoptosis in mice bone marrow cells. Aqueous root extract (ARE) of Inula racemosa (100, 200 and 400 mg/kg bw) with and without 4-NQO along with vehicle control (H2O) were administered orally for five consecutive days. 4-NQO (7.5 mg/kg bw) was injected intraperitoneally to the mice on the sixth day. After 24 h, the animals were sacrificed and extracted bone marrow cells were used for micronuclei and apoptotic analysis. Antiapoptotic effect of ARE (400 mg/kg bw) was measured by the use of Annexin V-FITC assay kit. 4-NQO generated the frequency of micronucleated polychromatic erythrocytes (MnPCEs) by about 4.7 times the control value, 14.29 MnPCEs/2500 PCEs. Pretreatment with ARE significantly reduced the MnPCEs frequency (39-72%) with respect to their doses, and increased PCEs/NCEs ratio was observed over the 4-NQO alone. 4-NQO-induced total apoptotic cells were about 12% over the control which was significantly (P < 0.05) brought down to 3.5% by pretreatment with 400 mg/kg bw of ARE. This was the first report that recorded the protective effects of I. racemosa on 4-NQO-induced DNA damage and apoptosis in mice bone marrow cells.

Effects of sesame oil on the reproductive parameters of diabetes mellitus-induced male rats

PURPOSE

The purpose of the present study was to investigate the effect of sesame oil on the reproductive parameters of diabetic male Wistar rats.

MATERIALS AND METHODS

The adult male rats in a split plot design were divided into normal (n=10), normal 5% (n=5; 5% sesame oil enriched diet), diabetic (Streptozocin induced diabetes; n=9), diabetic 5% (n=9; 5% sesame oil enriched diet), and diabetic 10% (n=9; 10% sesame oil enriched diet) groups. Diet supplementation continued for 56 days.

RESULTS

Sesame oil supplementation did not reduce the plasma glucose concentration of rats in the diabetic groups (p>0.05). The total spermatogonia, spermatocytes, Leydig cells/tubule, and the germ cell to Sertoli cell ratio were lower in the diabetic rats than the normal ones (p<0.05), and with the exception of spermatogonia counts, these values improved by the addition of sesame oil to the diet (p<0.05). The sperm progressive motility and viability were lower in the diabetic rats (p<0.05) and sesame oil supplementation did not improve them. Incorporation of sesame oil into the diet improved the plasma testosterone concentration of the diabetic rats in a dose-dependent manner (p<0.05).

CONCLUSIONS

In summary, sesame oil supplementation improved the reproductive parameters of diabetic rats at the levels of the testicular microstructure and function, but was not effective in protecting the epididymal sperm.

Sesamolinol glucoside, disaminyl ether, and other lignans from sesame seeds

The application of a procedure based on XAD-4 adsorption resin permitted the obtainment of an enriched polyphenolic extract from Sesamum indicum seeds. Chemical analysis of the obtained extract led to the identification of 12 lignans. Among them, 2 lignans, (+)-sesamolinol-4'-O-β-D-glucoside and disaminyl ether, are reported for the first time as natural compounds. Their structure has been determined by spectroscopic methods, mainly by the application of one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR) techniques [heteronuclear multiple-quantum coherence (HMQC), heteronuclear multiple-bond correlation (HMBC), and nuclear Overhauser effect spectrometry (NOESY)] and mass spectroscopy. The isolated compounds were evaluated for their antimutagenic activity. Among the tested lignans, the most active lignan was found to be sesamolin, followed by sesamolinol and samin, against H(2)O(2). Additionally, some of the tested lignans showed desmutagenic activity against benzo[a]pyrene (BaP).