The ameliorative effect of thymol against hydrocortisone-induced hepatic oxidative stress injury in adult male rats

Thymol's modulation of cellular macromolecules, oxidative stress, DNA damage, and NF-kB/caspase-3 signaling in the liver of imidacloprid-exposed rats

We evaluated whether thymol (THY) (30 mg/kg b.wt) could relieve the adverse effects of the neonicotinoid insecticide imidacloprid (IMD) (22.5 mg/kg b.wt) on the liver in a 56-day oral experiment and the probable underlying mechanisms. THY significantly suppressed the IMD-associated increase in hepatic enzyme leakage. Besides, the IMD-induced dyslipidemia was considerably corrected by THY. Moreover, THY significantly repressed the IMD-induced hepatic oxidative stress, lipid peroxidation, DNA damage, and inflammation. Of note, the Feulgen, mercuric bromophenol blue, and PAS-stained hepatic tissue sections analysis declared that treatment with THY largely rescued the IMD-induced depletion of the DNA, total proteins, and polysaccharides. Moreover, THY treatment did not affect the NF-kB p65 immunoexpression but markedly downregulated the Caspase-3 in the hepatocytes of the THY+IMD-treated group than the IMD-treated group. Conclusively, THY could efficiently protect against IMD-induced hepatotoxicity, probably through protecting cellular macromolecules and antioxidant, antiapoptotic, and anti-inflammatory activities.

Thymol abates the detrimental impacts of imidacloprid on rat brains by lessening oxidative damage and apoptotic and inflammatory reactions

Imidacloprid (IMID) is one of the most widely used neonicotinoid insecticides globally and, consequently, a probable widespread environmental contaminant. The potential neurotoxic effects of IMID have been previously reported. This study aimed to investigate the possible beneficial effect of thymol (TML) in relieving IMID-induced harmful effects on the brain of male Sprague-Dawley rats. For this aim, four groups (10 rats/group) were orally administered corn oil, TML (30 mg/kg b.wt), IMID (22.5 mg/kg b.wt), or TML + IMID for 56 days. The brain tissues were biochemically, histopathologically, and immunohistochemically evaluated. The results displayed that TML significantly restored the IMID-induced depletion of the total antioxidant capacity of the brain tissues. At the same time, the IMID-associated increased levels of lipid peroxidation in terms of malondialdehyde content were markedly suppressed in the TML + IMID group. Also, TML oral dosing markedly reduced the release of inflammatory elements, including nitric oxide and myeloperoxidase, resulting from IMID exposure. Furthermore, the IMID-induced decrease in gamma-aminobutyric acid but the increase in acetylcholinesterase was considerably reversed by TML oral dosing. Additionally, TML oral administration significantly counteracted the IMID-induced brainepatic DNA damage, as revealed by the comet assay. Besides, a significant downregulatibrainepatic Caspase-3 was evident in the TML + IMID group compared to the IMID group. However, TML oral dosing has not significantly altered the IMID-induced nuclear factor (NF-κB p65) increase. Therefore, TML could be a protective agent against IMID-induced detrimental impacts on brain tissue, possibly through its antioxidant, antiapoptotic, and anti-inflammatory activities.

Oliveria decumbens Extract Exhibits Hepatoprotective Effects Against Bile Duct Ligation-Induced Liver Injury in Rats by Reducing Oxidative Stress

Background: Cholestasis is described as a disease in which bile flow from the liver is reduced or stopped, and due to its oxidative effects, irreversible consequences may occur. Due to the remarkable antioxidant properties of Oliveria decumbens (OD) and the contribution of oxidants to the progression of bile duct ligation (BDL)-induced cholestasis, Objectives: This research aimed to examine how the OD ethanolic extract affected liver damage and oxidant-antioxidant balance markers in BDL-induced cholestasis. Methods: Forty male Wistar rats weighing 200 - 250 g were used. Cholestasis was induced using the BDL approach. The rats were categorized into four groups: Group 1, sham control (SC); group 2, cholestatic; group 3, SC + OD; and group 4, cholestatic + OD. A dose of OD ethanolic extract was administered orally (500 mg/kg/day) to rats for seven days. Seven days following surgery, the rats’ blood samples were collected; after sacrifice, a part of the liver tissue was isolated. A histopathological examination was performed, while the rest was stored at -70°C in liquid nitrogen. Heparin-containing tubes were used to gather blood samples. In plasma and hepatic tissue, biochemical tests, histopathological evaluations, and oxidative stress markers staining levels were performed. Results: Our findings showed that OD could effectively reduce liver injury by reducing the activity of liver function enzymes (AST and ALP). At the same time, it did not affect total bilirubin and protein. Bile duct ligation-induced hepatic markers of protein oxidation (PCO) and reactive nitrogen species (NO) were significantly decreased by OD, and it also promoted liver antioxidant capacity by enhancing superoxide dismutase (SOD) activities. Moreover, OD treatment prevented liver bile duct proliferative changes in histopathologic analysis. Conclusions: Our study confirmed that OD exerts substantial hepatoprotective activities against BDL-induced cholestasis by improving liver damage markers and regulating oxidative stress. It may be a beneficial therapeutic agent for managing cholestasis. Bioassay-guided isolation and identification of bioactive OD secondary metabolites can further direct the discovery of potential natural-based drug candidates.

A systematic review and meta-analysis of the effect of thymol as an anti-inflammatory and wound healing agent: A review of thymol effect on inflammation and wound healing: A review of thymol effect on inflammation and wound healing

Thymol (THY) exhibits antibacterial and antioxidant properties. Recent studies have also shown that THY presents anti-inflammatory and healing properties. This review focused on in vitro and in vivo investigations related to THY utilization, as an anti-inflammatory and/or wound healing agent. PubMed, WebOfScience, and Scopus were examined. Independent reviewers conducted all diagram steps. PRISMA was followed for data extraction. RoB 2 and SYRCLE were utilized to assess the risk of bias for in vitro and animal studies. Meta-analysis was performed for in vitro and in vivo articles that investigated THY as an anti-inflammatory agent. Thirty-six and 15 articles were included in the qualitative analysis and meta-analysis, respectively. Studies showed high risk of bias related to sampling, allocation procedures, randomization, and blinding. Even so, for in vitro studies, significant result was observed for IL-2. For in vivo studies, significant results were found for IL-1, IL-17, TNF-α, AST, MPO, and CRP, with higher levels noticed in control groups. THY presents significant properties as anti-inflammatory, ameliorating affections of the digestive system, cardiovascular problems, respiratory system and dermal damages, and burns. Researches are needed to clarify THY dose-response relationship and its mechanism of action, especially in the application of THY as a healing agent.

Effects of Dietary L-Theanine on Growth Performance, Antioxidation, Meat Quality, and Intestinal Microflora in White Feather Broilers With Acute Oxidative Stress

In order to reduce the negative effects caused by oxidative stress on broilers, it is particularly important to find ways to alleviate oxidative stress. As a natural plant extract, L-theanine has a variety of biological effects, such as improving antioxidant capacity, promoting growth, and enhancing immunity and antitumor. This trial evaluated the effects of dietary supplementation of L-theanine on growth performance, antioxidation, meat quality, and intestinal microflora in 817 White Feather Broilers. A total of 108 21-day-old 817 broilers with similar body weight (BW) were randomly divided into three groups with six replicates per group and six chickens within each replicate. The three groups were corn-soybean-based diet (NC group); basal diet plus drinking water with 30 mg hydrocortisone/kg (PC group); and basal diet supplemented with 400 mg L-theanine/kg plus drinking water with 30 mg hydrocortisone/kg (LT group). Compared with the NC group, from 21 to 24 days of age, the PC and LT groups had decreased BW, average daily gain (ADG), and average daily feed intake (ADFI), and increased feed to gain ratio (F/G; p < 0.05). At 24 days of age, the LT group had improved superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities in serum as compared to the NC group (p < 0.05). The LT group broilers also had significantly higher concentrations of malondialdehyde (MDA) in serum and liver (p < 0.05). On the 42nd days, the PC group had lower PH_45min (p < 0.05) than the NC and LT groups and higher cooking loss and shear force (p < 0.05). Moreover, the villi height of the PC group was significantly lower in jejunum than the NC group (p < 0.05). The LT group had a higher ZO-1 content in duodenum than the NC and PC groups (p < 0.05). The activity of GSH-Px in the liver of the LT group was increased than in the PC group (p < 0.05). The relative abundance of Firmicutes in the LT group was significantly higher than in the NC and PC groups (p < 0.05). These results suggested that the effects of acute oxidative stress on growth performance and meat quality of broilers are continuous, and dietary supplementation of L-theanine could improve the growth performance and meat quality, enhance the intestinal mucosal barrier and antioxidant capacity, and improve the composition of the intestinal flora of broilers caused by acute oxidative stress.

Thymol ameliorated neurotoxicity and cognitive deterioration in a thioacetamide-induced hepatic encephalopathy rat model; involvement of the BDNF/CREB signaling pathway

In the present study, we aimed to delineate the neuroprotective potential of thymol (THY) against neurotoxicity and cognitive deterioration induced by thioacetamide (TAA) in an experimental model of hepatic encephalopathy (HE). Rats received TAA (100 mg kg^-1, intraperitoneally injected, three times per week) for two weeks. THY (30 and 60 mg kg^-1), and Vit E (100 mg k^-1) were administered daily by oral gavage for 30 days after HE induction. Supplementation with THY significantly improved liver function, reduced serum ammonia level, and ameliorated the locomotor and cognitive deficits. THY effectively modulated the alteration in oxidative stress markers, neurotransmitters, and brain ATP content. Histopathology of liver and brain tissues showed that THY had ameliorated TAA-induced damage, astrocyte swelling and brain edema. Furthermore, THY downregulated NF-kB and upregulated GFAP protein expression. In addition, THY significantly promoted CREB and BDNF expression at both mRNA and protein levels, together with enhancing brain cAMP level. In conclusion, THY exerted hepato- and neuroprotective effects against HE by mitigating hepatotoxicity, hyperammonemia and brain ATP depletion via its antioxidant, anti-inflammatory effects in addition to activation of the CREB/BDNF signaling pathway.

A Protein from Dioscorea polystachya (Chinese Yam) Improves Hydrocortisone-Induced Testicular Dysfunction by Alleviating Leydig Cell Injury via Upregulation of the Nrf2 Pathway

Leydig cell injury has been described as a primary driver of testicular dysfunction and is affected by oxidative stress. Dioscorea polystachya (Chinese yam) is used to improve testicular dysfunction in clinical and pharmacological research via its antioxidative activity, but the mechanisms underlying the beneficial effect of Chinese yam on testicular dysfunction and its suppression of Leydig cell oxidative damage remain unclear. In this study, we obtained a Chinese yam protein (DP1) and explored its effectiveness and possible mechanism in improving testicular dysfunction in vivo and in vitro. We established a testicular dysfunction model in rats using hydrocortisone (HCT). DP1 increased body weight and organ index, improved the deterioration in testicular morphology (including increasing the diameter of seminiferous tubules and thickness of germinal cell layers, inhibiting testicular cell apoptosis by increasing the Bcl-2/Bax ratio, and impeding collagen leakage by downregulating TGF-β1 and p-SMAD2/3 expression), and restored the testosterone content. In addition, DP1 enhanced the number of Leydig cells in rats and H₂O₂-induced TM3 Leydig cells, and the effect of DP1 on the apoptosis, fibrosis, and testosterone content of TM3 cells was similar to that observed in vivo. These changes were dependent on the regulation of oxidative stress, including significantly reduced intracellular 8-hydroxy-2-deoxyguanosine levels, enhanced superoxide dismutase activities, and decreased superoxide anion levels, which were confirmed via a superoxide overexpression system. Furthermore, we observed that DP1 promoted Nrf2 nuclear import and upregulated antioxidant factor expression in vivo and in vitro. However, Nrf2 silencing eliminated the ability of DP1 to increase the Bcl-2/Bax ratio, reduce the expression levels of TGF-β1 and p-SMAD2/3, and increase testosterone contents in H₂O₂-induced TM3 cells. In conclusion, DP1 reversed the HCT-induced testicular apoptosis and fibrosis and decreased testosterone contents by alleviating Leydig cell oxidative damage via upregulation of the Nrf2 pathway.

Thymol alleviates imidacloprid-induced testicular toxicity by modulating oxidative stress and expression of steroidogenesis and apoptosis-related genes in adult male rats

The present work was designed to assess the potential ameliorative effect of thymol on the testicular toxicity caused by imidacloprid (IMI) in adult male rats. Forty adult male rats were allocated into four groups; control group was given corn oil, thymol-treated group (30 mg/kg b.wt), IMI-treated group (22.5 mg/kg b.wt), and IMI + thymol-treated group. All administrations were done by gavage every day for duration of 56 days. As a result, the IMI exposure caused a significant decline in the body weight change, reproductive organ weights, sperm functional parameters, and serum level of testosterone, widespread histological alterations, and apoptosis in the testis. Additionally, the IMI-treated rats exhibited a remarkable increment in the serum levels of follicle stimulating hormone and luteinizing hormone. Also, IMI induced testicular oxidative stress, as indicated by elevated malondialdehyde (MDA) levels and a marked decline in the activity of antioxidant enzymes and reduced glutathione (GSH), and total antioxidant capacity (TAC) levels. Moreover, IMI treatment significantly downregulated the mRNA expression of steroidogenic genes and proliferating cell nuclear antigen (PCNA) immunoexpression in the testicular tissue. However, thymol co-administration significantly mitigated the IMI-induced toxic effects. Our findings suggested that IMI acts as a male reproductive toxicant in rats and thymol could be a potential therapeutic option for IMI reprotoxic impacts.

Protective effects of orally administered thymol against titanium dioxide nanoparticle-induced testicular damage

In this study, we investigated the potential of thymol and its mode of action to protect against the titanium dioxide (TiO2) nanoparticle-induced testicular damage. Twenty-four rats were randomly divided into four groups: control group, TiO2 (100 mg/kg BW/day) group, TiO2 + thymol (10 mg/kg BW/day) group, and TiO2 + thymol (30 mg/kg BW/day) group. With the exception of the control group, all animals received orally TiO2 nanoparticles for 60 days. In treatment groups, animals were given orally thymol 1 h before TiO2 nanoparticles. Epididymal sperm parameters, testicular histopathology, and spermatogenesis assessments were performed for evaluation of the TiO2 and thymol effects on the testis. Furthermore, antioxidative enzyme activities such as catalase (CAT), glutathione peroxidase (GPx) and superoxide dismutase (SOD), and malondialdehyde (MDA), glutathione (GSH) levels and ferric-reducing antioxidant power (FRAP) value were measured. Intragastric administration of TiO2 for 60 consecutive days caused a significant decrease in sperm quality, widespread histopathological alteration, and significantly induced oxidative stress as manifested by elevated MDA levels and a remarkable decline in antioxidant enzyme activities such as CAT, SOD, and GPx, and also FRAP and GSH levels in testis tissue. Nearly all of these alterations were significantly ameliorated in the groups that orally received thymol before TiO2 nanoparticles administration. The results of this study demonstrated that thymol improved the spermatogenesis defects induced by TiO2 nanoparticles in rats in a dose-dependent manner by protecting the testes against the testicular toxicity. Reduction in TiO2 nanoparticle-induced oxidative stress may have a major role in this protective effect.

Effects of thymol and carvacrol on sperm quality and oxidant/antioxidant balance in rats

In this study, we have investigated the effects of different doses of thymol (T) and carvacrol (C) on sperm quality oxidative stress and antioxidant system. For this purpose, 49 rats were divided into seven groups (7 rats in each group): 1st Group (control); 2nd Group T-10 (thymol 10 mg/kg), 3rd Group T-20 (thymol 20 mg/kg), 4th Group C-10 (carvacrol 10 mg/kg), 5th Group C-20 (carvacrol 20 mg/kg), 6th Group T + C-10 (thymol 10 mg/kg + carvacrol 10 mg/kg) and 7th Group T + C-20 (thymol 20 mg/kg + carvacrol 20 mg/kg). The duration of the experiment was 10 weeks for all animals. During the study, sperm quality parameters (motility, concentration, abnormal spermatozoa and live-dead sperm ratio), biochemical parameters [malondialdehyde (MDA), reduced glutathione(GSH), glutathione peroxidase (GSH-Px), catalase (CAT), AST, ALT, GGT, urea and creatinine] were analysed, and histopathological examination was performed. The study results showed that monotherapies of thymol and carvacrol significantly decreased MDA levels in testicles, liver and kidney tissues compared to the control group (p < .001). GSH levels increased only with the thymol administration and GSH-Px and catalase activity increased only with the carvacrol administration compared to the control group (p < .05). The combined administration of these two agents did not cause any significant change in any parameter. Regarding the sperm quality parameters, only the spermatozoa concentration and motility increased significantly in the thymol and carvacrol groups compared to the control group (p < .01). However, these parameters decreased in the 7th Group (T + C-20) compared to the control group (p < .001). Considering the dead sperm ratio decreased significantly in the 2nd (T-10), 3rd (T-20), 4th (C-10), 5th (C-20) and 6th Group (T + C-10) compared to the control group (p < .001). In respect of spermatozoon anomaly, there was a significant decrease in thymol and carvacrol monotherapy groups. The histopathological analysis of the testicle, liver and kidney tissues of the animals showed no difference between the groups. In conclusion, we have determined that thymol and carvacrol administration decreased the oxidative damage and increased the antioxidant levels and improved the sperm quality parameters. However, the combined use of these two active ingredients had a limited therapeutic effect on the mentioned parameters.

Hepatoprotective Role of Thymol in Drug-Induced Gastric Ulcer Model

INTRODUCTION AND AIM

Indo is widely one of the non-steroidal anti-inflammatory drugs and one of the common toxic effects of this drug is hepatic failure. Thymol is a monoterpene phenol with many different pharmacological activities. However, up to now its hepatoprotective effects on Indo-induced gastric ulcer model in rats have not been explored yet.

MATERIAL AND METHODS

Thirty five Sprague-Dawley rats were divided into seven groups: control, ulcer control (30 mg/kg Indo), Indo + reference standard (50 mg/kg Rantidine), Indo + Thymol (75, 100, 250 and 500 mg/kg) groups. 10 minutes after the induction of ulcer with Indo; Thymol was orally administered to the rats. Liver function enzymes (AST, ALT and LDH) were measured from serum samples. TOS/TAC, TNF-α and PGE2 levels, eNOS and Caspase-3 activity were assessed from tissue homogenate samples. In addition, histopathologic analysis on liver sections was performed.

RESULTS

Indo significantly increased the levels of hepatic enzymes, TNF-α and eNOS, and caspase-3 activation, while decreased PGE2 levels. Furthermore, it induced oxidative stress as evidenced by elevated TOS and decreased TAC levels. However, Thymol treatment induced a significant improvement in these parameters, especially in 250 mg/kg dose. On the other hand, treatment with Thymol 500 mg/kg dramatically affected the parameters much worse than the Indo treated group.

CONCLUSION

The findings of the current study demonstrated that Thymol administration significantly ameliorated liver injury due to Indo toxicity. This effect of Thymol (250 mg/kg) may be mediated by its anti-oxidative or anti-inflammatory effect, and up-regulation the synthesis of PGE2.

Montelukast abrogates prednisolone-induced hepatic injury in rats: Modulation of mitochondrial dysfunction, oxidative/nitrosative stress, and apoptosis

The aim of this study was to investigate the protective effect of montelukast (MTK) against prednisolone-induced hepatic injury in rats. Twenty-eight male albino rats were categorized into four equal groups. Group I served as the control group; group II: rats orally received prednisolone (5 mg·kg-1 ·d-1 ) for 30 days; groups III and IV: rats orally received MTK at 10 and 20 mg·kg-1 ·d-1 , respectively, simultaneously with prednisolone for 30 days. Serum liver enzymes, hepatic mitochondrial function, oxidative/nitrosative stress, and inflammatory and apoptotic markers were evaluated, and the results were confirmed by histopathological examination. MTK showed significant hepatic protection evidenced by alleviated histological lesion and improvement of mitochondrial function, oxidative/nitrosative stress, and inflammatory and apoptotic changes induced by prednisolone, with more profound protection in higher MTK dose (20 mg·kg-1 ). In view of these findings, we can conclude that MTK may have hepatoprotective potential, beyond its therapeutic value for asthmatic patients during their course of corticosteroid therapy.

Blood-brain barrier breakdown, memory impairment and neurotoxicity caused in mice submitted to orally treatment with thymol

Several evidences have related the biochemical and pharmacological properties of thymol, but the possible neurotoxic effects of this compound remain unknown and not evaluated. Thus, the purpose of this study was to evaluate whether intake of thymol in different doses (10, 20 and 40 mg/kg) induce neurotoxicity and behavioral alterations using mice as experimental model, as well as the involvement of blood-brain barrier (BBB) and brain neurotransmitters in these alterations. Thymol (20 and 40 mg/kg) significantly decrease latency time to inhibitory avoidance task when compared to control group, indicating a memory loss after 30 days of oral treatment. Also, thymol (20 and 40 mg/kg) induced a significant increase on BBB permeability to Evan's blue dye when compared to control group, which is an indicative of BBB breakdown. Moreover, a significant increase of brain acetylcholinesterase (AChE) was observed in mice treated with 40 mg/kg of thymol, while the activity of sodium-potassium pump (Na⁺, K⁺-ATPase) was inhibited in mice treated with 20 and 40 mg/kg thymol when compared to control group. Finally, mice that received 20 and 40 mg/kg thymol showed a significant increase on cerebral reactive oxygen species (ROS) levels and cerebral xanthine oxidase (XO) activity compared to control group. Based on these evidences, the rupture of BBB can be considered an important pathway linked in thymol-induced memory loss. Also, the augmentation of brain ROS levels elicited by increase on XO activity may be a via involved in the damage to BBB, and an oxidative pathway that impairs the activity of brain neurotransmitters, as AChE and Na⁺, K⁺-ATPase. In summary, the dose of 10 mg/kg thymol can be safe and without neurotoxic effects in a period of 30 days of intake.

Aflatoxicosis in African greater cane rats (Thryonomys swinderianus)

Aim:

Aflatoxicosis is a widespread problem in captive animals fed on stored food and has been reported in various animals both domestic and wild. This report documents the clinicopathologic, microbial diagnostic findings and therapeutic regime for a study on the presentation, management, and outcome of aflatoxicosis in greater cane rats.

Materials and Methods:

A total of 65 greater cane rats suspected to be exposed to the toxin were examined clinically along with their environment. Feed samples, recently deceased carcasses and some moribund carcasses were collected for the study. Carcasses were subjected to gross and histopathologic investigations while feed and organs were subjected to microbiological investigations.

Results:

Gross lesions included hepatic lipidosis with ecchymotic hemorrhages, distended gallbladder, and renomegaly with ecchymosis among others. Histopathology revealed loss of hepatocellular architecture with massive centrilobular hepatocyte necrosis and diffuse steatotic damage characterized by macrovacuoles. Other histologic findings included pulmonary congestion, moderate renal tubular degeneration, and necrosis of epithelial tubular cells. Aspergillus flavus was isolated from the feed and ingesta. Total aflatoxin detected in feed sample was found to be over 400 ppm. Klebsiella species, Staphylococcus species, and Bacillus species were isolated from the liver and intestinal content. Management was attempted using Fungizal^® (Avico, Jordan) (which contains Thymol, benzoic acid, sorbic acid, and kaolin) and Orego-Stim^® (Saife, USA) (which contains carvacrol and thymol) which were instituted in feed and Superliv^® (Ayurvet, India) (polyherbal) liquid was instituted in water for 5 days at manufacturers’ dosage. All clinical signs disappeared, and no more deaths were recorded following management.

Conclusion:

This report concludes that aflatoxicosis causes severe mortality in greater cane rats and can be prevented and managed successfully.

Hepatoprotective effect of thymol against subchronic toxicity of titanium dioxide nanoparticles: Biochemical and histological evidences

The study was aimed to investigate the protective action of thymol against nano titanium dioxide (nano-TiO₂) induced hepatotoxicity in rats. To achieve this purpose, the rats were divided into four groups (n = 6) including control, nano-TiO₂ (100 mg/kg), nano-TiO₂ + thymol (10 mg/kg) and nano-TiO₂ + thymol (30 mg/kg). Intragastric (IG) administration of nano-TiO₂ for 60 consecutive days caused widespread histological changes and significantly induced oxidative stress in the liver tissues as manifested by the rise in serum transaminase activities accompanied by marked decline of enzymatic (catalase, superoxide dismutase and glutathione peroxidase) and non-enzymatic (ferric reducing antioxidant power and glutathione) antioxidant levels, and rise of malondialdehyde levels in liver tissue. Pretreatment with thymol (IG) prior to nano-TiO₂ administration significantly ameliorated all of biochemical and histopathological alterations in a dose-dependent manner. In conclusion, thymol effectively protects against nano-TiO₂-induced hepatotoxicity in rats by its antioxidant properties.

Preventive and Therapeutic Effects of Thymol in a Lipopolysaccharide-Induced Acute Lung Injury Mice Model

Acute lung injury (ALI) is a life-threatening syndrome which causes a high mortality rate worldwide. In traditional medicine, lots of aromatic plants-such as some Thymus species-are used for treatment of various lung diseases including pertussis, bronchitis, and asthma. Thymol, one of the primary active constituent derived from Thymus vulgaris (thyme), has been reported to exhibit potent anti-microbial, anti-oxidant, and anti-inflammatory activities in vivo and in vitro. The present study aims to investigate the protective effects of thymol in lipopolysaccharide (LPS)-induced lung injury mice model. In LPS-challenged mice, treatment with thymol (100 mg/kg) before or after LPS challenge significantly improved pathological changes in lung tissues. Thymol also inhibited the LPS-induced inflammatory cells influx, TNF-α and IL-6 releases, and protein concentration in bronchoalveolar lavage fluid (BALF). Additionally, thymol markedly inhibited LPS-induced elevation of MDA and MPO levels, as well as reduction of SOD activity. Further study demonstrated that thymol effectively inhibited the NF-κB activation in the lung. Taken together, these results suggested that thymol might be useful in the therapy of acute lung injury.

Effect of tanshinone IIA on oxidative stress and apoptosis in a rat model of fatty liver

Oxidative stress is a crucial factor associated with fatty liver disease, which raises the possibility of using antioxidants to improve liver steatosis. Tanshinone IIA (TSIIA) is a traditional Chinese medicine that has been reported to have antioxidant effects in vitro. The present study aimed to investigate whether TSIIA possesses antioxidant effects in vivo and whether TSIIA was able to improve liver steatosis. Hence, the ability of TSIIA to protect rats from liver disease was explored, particularly in regard to antioxidant activity. Rats were fed a high-lipid diet for 90 days, causing severe liver steatosis, both morphologically and biochemically. An increase in reactive oxygen species (ROS) in the liver was exhibited in addition to significantly elevated serum lipids and malondialdehyde (MDA). Furthermore, hepatocyte apoptosis was measured by Hoechst staining, reverse transcription-quantitative polymerase chain reaction and western blot analysis and an increase in hepatocyte apoptosis rate was indicated in mice on a high-fat diet. Following intraperitoneal injection of TSIIA (10 mg/kg/day), liver steatosis was significantly inhibited. In rats receiving TSIIA treatment, less ROS were indicated in the liver and significantly decreased levels of MDA (P<0.05) in serum were exhibited, whereas significantly increased activities of total superoxide dismutase (T-SOD) and glutathione peroxidase (GSH-PX) were observed (P<0.05 and P<0.01, respectively). In addition, the rate of hepatocyte apoptosis was significantly decreased in the TSIIA group (P<0.01). However, TSIIA elicited no effect on serum lipid profiles. These results suggest that TSIIA attenuates oxidative stress by decreasing ROS and MDA production and enhancing the activity of T-SOD and GSH-PX, which may contribute to the inhibition of apoptosis and amelioration of liver steatosis.

Pharmacological Properties and Molecular Mechanisms of Thymol: Prospects for Its Therapeutic Potential and Pharmaceutical Development

Thymol, chemically known as 2-isopropyl-5-methylphenol is a colorless crystalline monoterpene phenol. It is one of the most important dietary constituents in thyme species. For centuries, it has been used in traditional medicine and has been shown to possess various pharmacological properties including antioxidant, free radical scavenging, anti-inflammatory, analgesic, antispasmodic, antibacterial, antifungal, antiseptic and antitumor activities. The present article presents a detailed review of the scientific literature which reveals the pharmacological properties of thymol and its multiple therapeutic actions against various cardiovascular, neurological, rheumatological, gastrointestinal, metabolic and malignant diseases at both biochemical and molecular levels. The noteworthy effects of thymol are largely attributed to its anti-inflammatory (via inhibiting recruitment of cytokines and chemokines), antioxidant (via scavenging of free radicals, enhancing the endogenous enzymatic and non-enzymatic antioxidants and chelation of metal ions), antihyperlipidemic (via increasing the levels of high density lipoprotein cholesterol and decreasing the levels of low density lipoprotein cholesterol and low density lipoprotein cholesterol in the circulation and membrane stabilization) (via maintaining ionic homeostasis) effects. This review presents an overview of the current in vitro and in vivo data supporting thymol's therapeutic activity and the challenges concerning its use for prevention and its therapeutic value as a dietary supplement or as a pharmacological agent or as an adjuvant along with current therapeutic agents for the treatment of various diseases. It is one of the potential candidates of natural origin that has shown promising therapeutic potential, pharmacological properties and molecular mechanisms as well as pharmacokinetic properties for the pharmaceutical development of thymol.

Vitamin D3 protects against prednisolone-induced liver injury associated with the impairment of the hepatic NF-κB/iNOS/NO pathway

The study was carried out to define whether prednisolone-induced damage to hepatic cells is accompanied by excessive nitric oxide (NO) levels associated with nuclear factor kappa B (NF-κB)/inducible NO synthase (iNOS) activation and evaluate the efficacy of the treatment with vitamin D3. Histopathological examination, activities of liver transaminases (alanine aminotransferase and aspartate aminotransferase), and cell death assays consistently showed that prednisolone (5 mg/kg body weight, 30 days) induces chronic liver injury in female Wistar rats. Specifically, increased hepatocellular necrosis and caspase-3-dependent apoptosis were observed. Prednisolone enhanced iNOS protein expression, NO generation, and tyrosine nitration in liver cells. Despite unchanged hepatic level of the NF-κB/p65 protein, prednisolone increased inhibitory κB-α (IκB-α) degradation, nuclear translocation, and phosphorylation of NF-κB/p65 at Ser311, indicating that NF-κB activation can be involved in the induction of iNOS/NO. All changes were associated with a 2.9-fold decrease in the serum content of 25-hydroxyvitamin D3 and significant reduction of hepatic vitamin D3 receptor (VDR) expression that points reliably to vitamin D3 deficiency and failures in VDR signaling. Vitamin D3 co-administration (100 IU/rat, 30 days) prevented glucocorticoid-evoked abnormalities in hepatic tissue. In conclusion, prednisolone-induced liver disturbances were associated with the impairment of NF-κB/iNOS/NO responses that can be ameliorated by vitamin D3 treatment through VDR-mediated mechanisms.

Chronic Glucocorticoid-Rich Milieu and Liver Dysfunction

We investigated the impact of chronic hypercorticosteronemia (due to neonatal monosodium L-glutamate, MSG, and treatment) on liver oxidative stress (OS), inflammation, and carbohydrate/lipid metabolism in adult male rats. We evaluated the peripheral concentrations of several metabolic and OS markers and insulin resistance indexes. In liver we assessed (a) OS (GSH and protein carbonyl groups) and inflammatory (IL-1b, TNFa, and PAI-1) biomarkers and (b) carbohydrate and lipid metabolisms. MSG rats displayed degenerated optic nerves, hypophagia, low body and liver weights, and enlarged adipose tissue mass; higher peripheral levels of glucose, triglycerides, insulin, uric acid, leptin, corticosterone, transaminases and TBARS, and peripheral and liver insulin resistance; elevated liver OS, inflammation markers, and glucokinase (mRNA/activity) and fructokinase (mRNA). Additionally, MSG liver phosphofructokinase-2, glucose-6-phosphatase (mRNA and activity) and glucose-6-phosphate dehydrogenase, Chrebp, Srebp1c, fatty acid synthase, and glycerol-3-phosphate (mRNAs) were increased. In conclusion adult MSG rats developed an insulin-resistant state and increased OS and serious hepatic dysfunction characterized by inflammation and metabolic signs suggesting increased lipogenesis. These features, shared by both metabolic and Cushing's syndrome human phenotypes, support that a chronic glucocorticoid-rich endogenous environment mainly impacts on hepatic glucose cycle, displacing local metabolism to lipogenesis. Whether correcting the glucocorticoid-rich environment ameliorates such dysfunctions requires further investigation.