The protective effects of carvacrol and thymol against paracetamol-induced toxicity on human hepatocellular carcinoma cell lines (HepG2)

Acetaminophen (APAP) overdose could induce liver damage and lead to acute liver failure. The treatment of APAP overdoses could be improved by new therapeutic strategies. Thymus spp., which has many beneficial effects and has been used in folk medicine, is one such potential strategy. In the present study, the hepatoprotective activity of the main constituents of Thymus spp., carvacrol and thymol, were evaluated in light of APAP-induced hepatotoxicity. We hoped to understand the hepatoprotective mechanism of these agents on the antioxidant system and pro-inflammatory cytokines in vitro. Dose-dependent effects of thymol and carvacrol (25, 50, and 100 µM) were tested on cultured HepG2 cells. N-Acetylcysteine (NAC) was tested as positive control. We showed that APAP inhibited HepG2 cell growth by inducing inflammation and oxidative stress. Incubating APAP-exposed HepG2 cells with carvacrol and thymol for 24 h ameliorated this inflammation and oxidative stress. We also evaluated alanine transaminase and lactate dehydrogenase levels of HepG2 cells. We found that thymol and carvacrol protected against APAP-induced toxicity in HepG2 cells by increasing antioxidant activity and reducing pro-inflammatory cytokines, such as tumor necrosis factor α and interleukin 1β. Taking together high-dose thymol and carvacrol treatment has an effect close to NAC treatment in APAP toxicity, but thymol has better treatment effect than carvacrol.

Effects of amlodipine on ischaemia/reperfusion injury in the rat testis

The aim of this study was to examine the effects of amlodipine (AML) in rat testicular torsion/detorsion damage. In this study, rats were divided into eight groups: (i) sham; (ii) testicular ischaemia, 2 h of ischaemia; (iii) testicular ischaemia/reperfusion (I/R), 2 h of ischaemia followed by 2 h of reperfusion; (iv) ischaemia + AML (5 mg kg(-1)) administered 30 min before ischaemia; (v) ischaemia + AML (10 mg kg(-1)) administered 30 min before ischaemia; (vi) and (vii) I/R + AML (5 mg kg(-1)) and I/R + AML (10 mg kg(-1)) administered 1.5 h after the induction of ischaemia, respectively, and at the end of a 2-h ischaemia period and a 2-h reperfusion period applied; and (viii) sham + AML (10 mg kg(-1)). Significant decreases in levels of superoxide dismutase and glutathione were observed in ischaemia and reperfusion groups when compared with healthy controls. These antioxidant levels increased in AML groups while malondialdehyde levels significantly decreased. While increases in tumour necrosis factor-alpha and transforming growth factor-beta levels were found in the torsion and detorsion groups, significant decreases in the levels of these inflammatory cytokines were observed in the treatment groups. These results demonstrate that AML significantly produced protective effects on testis tissue damage that occurs in the torsion/detorsion model via biochemical, histopathological and molecular pathways.

Endothelin receptor inhibition with bosentan delays onset of liver injury in streptozotocin-induced diabetic condition

BACKGROUND

This study was designed to investigate the protective effects of bosentan an orally active non-peptide mixed ETA/ETB receptor antagonist, on liver injury in streptozotocin-induced diabetic rats.

METHODS

24 Albino-Wistar rats were randomly divided into 4 groups: healthy (Group 1), diabetic (Group 2) (60 mg/kg of streptozotocin i.p.), diabetic treated with bosentan 50 mg/kg (Group 3) and diabetic treated with bosentan 100 mg/kg (Group 4). The treatment of bosentan was initiated after streptozocin injection and continued for 60 days.

RESULTS

Liver from diabetic rats showed significant increase in malondialdehyde (MDA) level and significant decrease in glutathione (GSH), and superoxide dismutase (SOD) activity. Endothelin (ET-1), tumor necrosis factor (TNF-α) and transforming growth factor beta (TGF-β) gene expression significantly increased in the diabetic groups in the rat liver tissue. Bosentan treatment showed a significant up-regulatory effect on ET-1, TNF-α and TGF-β mRNA expression. Results from histopathological evaluation of the liver were in accordance with our biochemical and molecular results.

CONCLUSIONS

These data provide clear evidence that bosentan treatment is associated with promising hepatoprotective effect against diabetes-induced liver damage via reduction of cell inflammation and oxidative damage. These data suggest that ET receptors may be an important actor in diabetes-related liver damage, and blockage of these receptors may become a target for preventing diabetic complications in the future.

Agomelatine

Paracetamol was shown to induce hepatotoxicity or more severe fatal acute hepatic damage. Agomelatine, commonly known as melatonin receptor agonist, is a new antidepressant, which resynchronizes circadian rhythms with subjective and objective improvements in sleep quality and architecture, as melatonin does. In the present study, it was aimed to evaluate the hepatoprotective activity of agomelatine on paracetamol-induced hepatotoxicity and to understand the relationship between the hepatoprotective mechanism of agomelatine and antioxidant system and proinflammatory cytokines. A total of 42 rats were divided into 7 groups as each composed of 6 rats: (1) intact, (2) 40 mg/kg agomelatine, (3) 140 mg/kg N-acetylcysteine (NAC), (4) 2 g/kg paracetamol, (5) 2 g/kg paracetamol + 140 mg/kg NAC, (6) 2 g/kg paracetamol + 20 mg/kg agomelatine, and (7) 2 g/kg paracetamol + 40 mg/kg agomelatine groups. Paracetamol-induced hepatotoxicity was applied and liver and blood samples were analyzed histopathologically and biochemically. There were statistically significant increases in the activities of aspartate aminotransferase, alanine aminotransferase, levels of tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) and 8-iso-prostane, and decreases in the activity of superoxide dismutase and level of glutathione in the group treated with paracetamol. Administration of agomelatine and NAC separately reversed these changes significantly. In conclusion, agomelatine administration protects liver cells from paracetamol-induced hepatotoxicity via antioxidant activity and reduced proinflammatory cytokines, such as TNF-α and IL-6.

Prevention of bone loss by Panax ginseng in a rat model of inflammation-induced bone loss

This study evaluated the protective effect of Panax Ginseng (PG) on bone metabolism in an experimental ovariectomy (OVX) model of osteoporosis in which inflammation was induced by subcutaneous magnesium silicate. The groups were: sham control (Group1, SH), sham+inflammation (Group2, SHinf), OVX (Group3), OVX+inflammation (Group4, OVXinf), OVX+inflammation+PG 100 mg/kg (Group5, OVXinf+PG1), OVX+inflammation+PG 200 mg/kg (Group6, OVXinf+PG2), OVX+PG 100 mg/kg (Group7, OVX+PG1), OVX+PG 200 mg/kg (Group8, OVX+PG1). After the OVX surgery, all the groups were allowed to recover for two months. On the 59th day after the OVX, inflammation was induced in Groups 2, 4, 5, and 6 by subcutaneous injections of magnesium silicate in the back of the animals. Groups 5 and 7 were administered oral PG 100 mg/kg, and Groups 6 and 8 were administered oral PG 200 mg/kg from the 60th to the 80th day. PG 200 mg/kg was able to restore BMD, up to values measured in both the OVX and the SH animals. The levels of OC and OP decreased in OVXinf+PG1 and OVXinf+PG2 groups. The serum levels of TNF—α, IL—1β, and IL—6 were increased significantly in the OVXinf rats compared with the SH group. The present data showed that PG protected against in the OVX model and in inflammation-induced bone loss rat model.

Nigella sativa as a potential therapy for the treatment of lung injury caused by cecal ligation and puncture-induced sepsis model in rats

We investigated the potential protective effects of Nigella sativa (NS) on mortality, serum levels of proinflammatory cytokines, oxidative stress and histopathological changes in lung tissues, in cecal ligation and puncture (CLP)-induced sepsis model in rats. Sepsis induction by CLP, determination of serum cytokine levels by ELISA, spectrophotometric determination of oxidative stress parameters, and histological examination of lung tissues. The rat groups were: 1) CLP group, 2) sham group, 3) NS500-sham group, 4) NS125, 5) NS250, 6) NS500 groups. NS treatment significantly decreased proinflammatory cytokine levels in serum; LPO level, MPO activity, and pathological changes in lung tissues, in CLP-induced sepsis, while significantly increasing GSH levels and SOD activity in the lung tissue. NS treatment after CLP potentially reduced mortality and may exert effects through the reduction in tissue oxidative stress and serum cytokines. The histopathological changes were minimized in lung tissue by NS, under sepsis conditions. We can suggest that NS reverses the systemic inflammatory reaction to polymicrobial sepsis and thereby reduces multiple organ failure. It may be suggested that role of the NS ethanolic extract in preventing formation of CLP induced sepsis, is due to the anti-inflammatory and antioxidant effects of the different compounds of the black seeds.

The inhibition of gastric mucosal lesion, oxidative stress and neutrophil-infiltration in rats by the lichen constituent diffractaic acid

The antiulcerogenic effect of diffractaic acid (DA) isolated from Usnea longissima, a lichen species, on indomethacin (IND)-induced gastric lesions was investigated in rats. Administration of 25, 50, 100 and 200 mg/kg doses of DA and ranitidine (RAN) (50 mg/kg dose) reduced the gastric lesions by 43.5%, 52.9%, 91.4%, 96.7% and 72.7%, respectively. It is known that oxidative stress leads to tissue injury in organisms. Thus, in all treated groups of rats, the in vivo activities of the antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and the levels of reduced glutathione (GSH) and lipid peroxidation (LPO) were evaluated. IND caused oxidative stress, which resulted in LPO in tissues, by decreasing the levels of GPx, SOD and GSH as compared to healthy rats. In contrast to IND, the administration of DA and RAN showed a significant decrease in LPO level and an increase in tissue SOD, GPx and GSH levels. However, while CAT activity was significantly increased by the administration of IND, the administration of DA and RAN decreased CAT activity. The administration of IND also increased the myeloperoxidase (MPx) activity, which shows neutrophil infiltration into the gastric mucosal tissues. In contrast to IND, the administration of DA and RAN decreased MPx activity. The changes in activities of gastric mucosal nitric oxide synthases (NOS) throughout the development of gastric mucosal damage induced by IND were also studied. A decrease in constitutive NOS (cNOS) activity and an increase in inducible NOS (iNOS) activity were determined in gastric damaged tissues induced by IND. The administration of DA (100 mg/kg dose) and RAN reversed the activities of iNOS and cNOS. These results suggest that the gastroprotective effect of DA can be attributed to its enhancing effects on antioxidant defense systems as well as reducing effects of neutrophil infiltration.

Effects of water extract of Usnea longissima on antioxidant enzyme activity and mucosal damage caused by indomethacin in rats

In this study, the antiulcerogenic effect of a water extract obtained from the lichen species Usnea longissima was investigated using indomethacin-induced ulcer models in rats. Experimental groups consisted of six rats. Antiulcerogenic activities of 50, 100 and 200mg/kg body wt. doses of the water extract were determined by comparing the negative (treated only with indomethacin) and positive (ranitidine) control groups. Although all doses of the water extract of U. longissima showed significant antiulcerogenic activity as compared to negative control groups, the highest activity was observed with 100 mg/kg body wt. doses (79.8%). The water extract of U. longissima showed moderate antioxidant activity when compared with trolox and ascorbic acids used as positive antioxidants. In addition, the activities of antioxidant enzymes [superoxide dismutase (SOD), catalase (CAT) and glutathione S-transferase (GST)] were determined in the stomach tissues of rats and compared with those of the negative and positive control groups to expose the effects of antioxidant enzymes on antiulcerogenic activity. SOD and GST enzymes activities in indomethacin-administrated tissues were reduced significantly by indomethacin in comparison to control groups. These enzymes were activated, however, by the water extracts of U. longissima. In contrast to SOD and GST activities, CAT activity was increased by indomethacin and reduced by all doses of U. longissima and ranitidine. The present results indicate that the water extract of U. longissima has a protective effect in indomethacin-induced ulcers, which can be attributed to its antioxidant potential.

Antioxidant activity, reducing power and total phenolic content of some lichen species

The total antioxidant activity, total phenolic content and reducing power of methanol and water extracts of four lichen species, Bryoria fuscescens, Dermatocarpon intestiniformis, Peltigera rufescens and Pseudevernia furfuracea, were determined in vitro. Water and methanol extracts of P. rufescens showed the highest antioxidant activity. However, there was no correlation between antioxidant activity and total phenolic content of the extracts. Although the methanol extract of P. furfuracea had the highest total phenolic contents, it exhibited low antioxidant activity. In contrast, there was a strong correlation between reducing power and total antioxidant activity of the extracts. The highest reducing power was determined for the methanol extract of P. rufescens.

Anti-inflammatory and antiulcerogenic effects of the aqueous extract of Lobaria pulmonaria (L.) Hoffm

An aqeuous extract of Lobaria pulmonaria (L.) Hoffm., from which a tea is prepared and consumed as treatment for various diseases in northeastern Turkey, was tested for its anti-inflammatory and antiulcerogenic effects in rats. The carrageenan-induced paw edema, cotton pellet granuloma and indomethacin-induced gastric damage models were used to determine these effects. The extract exhibited moderate anti-inflammatory and strong antiulcerogenic activities.