The association effect of insulin and clonazepam on oxidative stress in liver of an experimental animal model of diabetes and depression

Abstract

Context: It is known that oxidative stress occurs in peripheral blood in an experimental animal model of diabetes and depression, and acute treatment with insulin and clonazepam (CNZ) has a protective effect on oxidative stress in this model.

Objective: This study evaluated the effect of insulin plus CNZ on oxidative stress parameters in the liver of diabetic male rats induced with streptozotocin (STZ) and subjected to forced swimming test (FST).

Materials and methods: Diabetes was induced by a single intraperitoneal (i.p.) dose of STZ 60?mg/kg in male Wistar rats. Insulin (4?IU/kg) plus CNZ acute i.p. treatment (0.25?mg/kg) was administered 24, 5 and 1?h before the FST. Nondiabetic control rats received i.p. injections of saline (1?mL/kg). Protein oxidative damage was evaluated by carbonyl formation and the antioxidant redox parameters were analyzed by the measurements of enzymatic activities of the superoxide dismutase (SOD), catalase and glyoxalase I (GLO). Glycemia levels also were determined.

Results: Our present study has shown an increase in carbonyl content from diabetic rats subjected to FST (2.04?±?0.55), while the activity of catalase (51.83?±?19.02) and SOD (2.30?±?1.23) were significantly decreased in liver from these animals, which were reverted by the treatment. Also, the activity of GLO (0.15?±?0.02) in the liver of the animals was decreased.

Discussion and conclusion: Our findings showed that insulin plus CNZ acute treatment ameliorate the antioxidant redox parameters and protect against protein oxidative damage in the liver of diabetic rats subjected to FST.     

Rutin ameliorates oxidative stress and preserves hepatic and renal functions following exposure to cadmium and ethanol

Context: Rutin (RUT) is an antioxidant flavonoid with well-known metal chelating potentials.

Objective: This study was designed to evaluate the protective effects of RUT against cadmium (Cd)?+?ethanol (EtOH)-induced hepatic and renal toxicity in rats.

Materials and methods: Wistar rats were treated with Cd (50?mg/kg) alone or in combination with EtOH (5?mg/kg) and RUT (25, 50 and 100?mg/kg) for 15?days. After treatment, the liver, kidney and serum were removed for biochemical assays by spectrophotometric methods.

Results: Serum, hepatic and renal malondialdehyde (MDA) levels were highest in the Cd?+?EtOH group and lowest in Cd?+?EtOH animals co-treated with the highest dose of RUT (2.98?±?0.34, 10.08?±?2.32, 4.99?±?1.21 vs. 1.69?±?0.33, 6.13?±?0.28, 3.66?±?1.12?μmol MDA/mg protein, respectively). The serum level of Cd was increased in the Cd?+?EtOH treated animals compared to Cd?+?EtOH animals co-treated with 100?mg/kg RUT (2.54?±?0.08 vs. 1.28?±?0.04?ppm). Furthermore, RUT at the highest dose protected against Cd?+?EtOH-induced elevation of bilirubin and uric acid levels as well as activities of lactate dehydrogenase and γ-glutamyl transferase (62.86?±?2.74 vs. 122.52?±?6.35?µmol/L; 1.77?±?0.35 vs. 3.23?±?0.55?mmol/L; 9.56?±?1.22 vs. 16.21?±?1.64?U/L; 288.92?±?40.12 vs. 159.8?±?18.01?U/L). The histo-pathological changes in the liver and kidney were also reduced in the Cd?+?EtOH animals co-treated with RUT in a dose-dependent manner.

Discussion and conclusion: RUT protected against the combined effects of Cd?+?EtOH on hepatic and renal functions and improved the antioxidant defence system in the blood.     

Antidiabetic,antihyperlipidaemic, and antioxidant activity of Syzygium densiflorum fruits in streptozotocin and nicotinamide-induced diabetic rats

Context Syzygium densiflorum Wall. ex Wight & Arn (Myrtaceae) has been traditionally used by local tribes of the Nilgiris, Tamil Nadu, India, for the treatment of diabetes, however, no definitive experimental studies are available.

Objective This study investigates the antidiabetic, antihyperlipidaemic and antioxidant activities of ethanol extract of S. densiflorum (EFSD) fruits in streptozotocin (STZ) and nicotinamide (NA)-induced diabetic rats.

Materials and methods Acute oral toxicity and oral glucose tolerance were assessed in normal rats. The antidiabetic, antihyperlipidaemic and antioxidant activities were investigated in STZ???NA-induced diabetic rats. Diabetic rats were orally administered with glibenclamide (10?mg/kg b.wt), EFSD (200, 400 and 800?mg/kg b.wt) for 28 d. Further, changes in the blood glucose level (BGL), biochemical parameters, antioxidants were observed and histology of pancreas was performed.

Results No toxicity and lethality were observed. Results of the following parameters are represented by treated versus disease control (STZ?+?NA) groups. BGL (161.33?±?22.8 versus 476.17?±?56.58?mg/dl), glycosylated haemoglobin (5.285?±?0.19 versus 8.05?±?0.55%), urea (40.32?±?1.96 versus 75.37?±?2.91?mg/dl), uric acid (1.2?±?0.07 versus 2.16?±?0.05?mg/dl), total cholesterol (89.3?±?5.14 versus 139.7?±?5.95?mg/dl) and triglycerides (79.65?±?2.52 versus 108.9?±?3.61?mg/dl) were significantly decreased, whereas haemoglobin (11.75?±?0.73 versus 7.95?±?0.42?g/dl), high‐density lipoprotein cholesterol (14.2?±?1.11 versus 6.97?±?0.84?mg/dl), total protein (45%) and liver glycogen (87%) were significantly increased in EFSD-treated diabetic group. Significant changes were observed in the enzymatic and non-enzymatic antioxidants in EFSD-treated groups (p?<?0.001). Histopathological examination showed the regeneration of β-cells in Islets of Langerhans.

Conclusion This study confirms the antidiabetic, antihyperlipidaemic and antioxidant activities of S. densiflorum fruits.     

Amelioration of hyperglycaemia and modulation of antioxidant status by Alcea rosea seeds in alloxan-induced diabetic rats

Context: Alcea rosea L. (Malvaceae) has various medicinal uses including anticancer, anti-inflammatory and analgesic properties. However, there is no report on its antidiabetic activity.

Objective: Alcea rosea seed extracts were evaluated for antihyperglycaemic and antioxidative potential in diabetic rats.

Materials and methods: Single intra-peritoneal injection of alloxan (130?mg/kg b.w.) was used for induction of diabetes in Albino Wistar rats. Antihyperglycaemic and antioxidant activities of methanol and aqueous extracts of Alcea rosea seed (100 and 300?mg/kg b.w.), administered orally on daily basis for 15 days, were assessed in vivo for fasting blood glucose level and antioxidant status of liver and pancreas. Metformin was used as a positive control.

Results: Aqueous and methanol extracts (300?mg/kg b.w.) decreased blood glucose level in diabetic rats by 24% and 46%, respectively. Administration of aqueous and methanol extracts at 300?mg/kg b.w. significantly (p?2O₂ decomposed/min/mg of protein), respectively. Similar results were observed for pancreas.

Discussion and conclusions: Antihyperglycaemic and antioxidative potentials of Alcea rosea seeds suggest its usefulness in management of diabetes and its complications. This is the first report on antidiabetic activity of this plant.     

Nephroprotective activity of Macrothelypteris oligophlebia rhizomes ethanol extract

Context: Macrothelypteris oligophlebia (Bak.) Ching (Thelypteridaceae) is a Chinese herbal medicine used traditionally for the treatment of diseases such as edema, boils, burns, and roundworms. However, research about the nephroprotective potential of this plant is not available.

Objective: Present study was designed to evaluate the protective effect of ethanol extract of M. oligophlebia rhizomes (EMO) on gentamicin (GM)-induced nephrotoxicity.

Materials and methods: Rats were intraperitoneal (i.p.) injected with GM (100?mg/kg) to induce nephrotoxicity and simultaneously EMO (250 and 500?mg/kg) was orally given to GM-treated rats for 8 days. Blood urea nitrogen (BUN), serum creatinine (Cr), malondialdehyde (MDA), nitric oxide (NO), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) were evaluated in renal tissues. Histopathological analysis was used for evaluation of the renal damage.

Results: Administration with GM-induced renal dysfunction in rats. Pre-treatment with EMO (500?mg/kg) significantly decreased the levels of BUN, Cr, MDA and NO (decreased BUN from 12.71?±?1.28 to 7.19?±?0.23 mmol/l, Cr from 39.77?±?5.34 to 19.17?±?0.90 μmol/l, MDA from 5.60?±?0.37 to 2.63?±?0.24 nmol/ml, and NO from 868.17?±?22.67 to 589.51?±?8.83 μmol/ml), and also restored the activities of renal antioxidant enzymes (SOD, CAT, and GSH-Px) (restored SOD from 1.59?±?0.17 to 2.94?±?0.13?U/mg protein, CAT from 3.22?±?0.34 to 10.57?±?0.27?U/mg protein, and GSH-Px from 9.11?±?1.29 to 20.72?±?1.83?U/mg protein).

Discussion and conclusion: Our results suggest that the rhizomes of M. oligophlebia potentially have a protective role in renal tissue against oxidative stress in acute renal failure.     

Study of antidepressant-like activity of an enriched phloroglucinol fraction obtained from Hypericum caprifoliatum

Context: Hypericum caprifoliatum Cham &; Schlecht (Guttiferae) extracts have a potential antidepressant-like effect in rodents. However, the molecular mechanisms by which these extracts exert this effect remain unclear.

Objective: This study evaluated the effect of HC1, a fraction obtained from H. caprifoliatum enriched in phloroglucinol derivatives, on the Na⁺, K⁺ ATPase activity in mouse brain and verified the influence of veratrine on the effect of HC1 in the forced swimming test (FST).

Materials and methods: Veratrine (0.06?mg/kg) and HC1 (360?mg/kg) were given alone or combined i.p. 60 and p.o. 30?min, respectively, before FST. The effect of single and repeated administration (once a day for 3 consecutive days) of HC1 (360?mg/kg) on Na⁺, K⁺ ATPase activity was evaluated ex vivo in the cerebral cortex and hippocampus of mice subjected or not to FST.

Results: HC1 reduced the immobility time (103.15?±?18.67?s), when compared to the control group (183.6?±?9.51?s). This effect was prevented by veratrine (151.75?±?22.19?s). Mice repeatedly treated with HC1 presented a significant increase in Na⁺, K⁺ ATPase activity, both in cerebral cortex (46?±?2.41?nmol Pi/min?mg protein) and hippocampus (49.83?±?2.31?nmol Pi/min?mg protein), in relation to the respective controls (30?±?2.66 and 29.83?±?2.31?nmol Pi/min?mg protein respectively).

Discussion and conclusion: The HC1 antidepressant-like effect on FST might be related to its capacity to inhibit Na⁺?influx. HC1 increases hippocampal and cortical Na⁺, K⁺ ATPase activities possibly through long-term regulatory mechanisms.     

Anti-rheumatic activity of Ananas comosus fruit peel extract in a complete Freund’s adjuvant rat model

Context: Rheumatoid arthritis is a chronic, autoimmune and systemic inflammatory disease, which targets synovial joints leading to joint destruction mediated in part by migration of inflammatory cells into the synovial tissue.

Objective: The present study evaluates the anti-rheumatic effect of a methanol extract of Ananas comosus (L.) Merr. (Bromeliaceae) peel in rats.

Materials and methods: Anti-rheumatic activity of crude extract of peels of A. comosus in complete Freund’s induced arthritis model in rats was studied at doses of 50, 100, 250 and 500?mg/kg b.w. for 21 days. Parameters such as paw size, levels of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), C-reactive proteins (CRP) and prostaglandins (PGE₂) were analysed.

Results: Oral administration of the extract significantly reduced the swelling in the paw of rats (EC₅₀ 65.1?±?2.95?mg/kg b.w.) with a maximal inhibition of 77.01?±?10.53% on 21st day at 500?mg/kg b.w. The extract also significantly reduced the levels of SOD, CAT and GPx in liver (EC₅₀ 26.84?±?16.37, 68.37?±?19.22, 106.54?±?34.81?mg/kg b.w., respectively), kidney (EC₅₀ 261.75?±?81.5, 176.38?±?8.08, 14.32?±?6.64, mg/kg b.w., respectively) and spleen (EC₅₀ 152.14?±?39.57, 83.97?±?14.6, 47.1?±?10.45?mg/kg b.w., respectively); and CRP (EC₅₀ 36.37?±?12.4?mg/kg b.w.) and PGE₂ (EC₅₀ 191.06?±?71.54?mg/kg b.w.) in tissue homogenate and serum, respectively, at 500?mg/kg b.w. as compared to arthritic control group.

Discussion and conclusion: These results suggest that A. comosus fruit peel extract exerts anti-rheumatic activity.     

Co-administration of walnut (Juglans regia) prevents systemic hypertension induced by long-term use of dexamethasone: a promising strategy for steroid consumers

Context: The long-term consumption of glucocorticoids (GCs) may induce serious adverse effects such as hypertension. There is sufficient evidence related to the benefit of walnuts on the cardiovascular system.

Objective: This study assesses the effect of methanol extract of walnut [Juglans regia L. (Juglandaceae)] on dexamethasone-induced hypertension and the possible mechanisms in Wistar rats.

Material and methods: Animals were randomized into control, kernel extract (100 and 200?mg/kg/d, orally), dexamethasone (0.03?mg/kg/d, subcutaneously), dexamethasone?+?kernel (100 and 200?mg/kg/d, separately), and dexamethasone?+?captopril (25?mg/kg/d, orally) groups. Animals were treated with water, kernel extract or captopril by gavage 4 d before and during 11 d of saline or dexamethasone treatment. On the 16th day, blood pressure (BP) was recorded and blood samples were collected to measure nitric oxide (NO). Animal hearts were frozen for measurement of malondialdehyde (MDA) and glutathione peroxidase (GPX).

Results: Dexamethasone increased the diastolic BP and MDA/GPX ratio in comparison with control group (128?±?7 vs. 105?±?3?mmHg, p?p?p?p?Conclusion: Similar to captopril, walnut extract normalized dexamethasone-induced hypertension. A part of this beneficial effect apparently involves maintaining balance of the redox system and NO production.     

Effects of garlic polysaccharide on alcoholic liver fibrosis and intestinal microflora in mice

Context: Alcoholic liver fibrosis (ALF) is treatable and reversible consequence of liver disease. Intestinal microflora plays an important role in the progression of liver disease. Garlic (Allium sativum L. [Amaryllidaceae]) has been consumed as a traditional medicine to treat liver injury.

Objective: To investigate the effects of garlic polysaccharide (GP) on ALF and intestinal microflora in mice.

Materials and methods: KM mice were orally administered with alcohol (56%, 6?mL/kg) for 30?d to establish ALF model, and divided into four groups together with control group (water only). Hugan tablet (60?mg/kg) or GP (250 and 150?mg/kg) were given 5?h after each dose of alcohol. Biochemical markers in serum and liver homogenate were determined with kits. Alteration of intestinal microflora, and protein expressions of TGF-β1, TNF-α and decorin were detected.

Results: In GP-H group, ALT and AST decreased to 18.85?±?4.71?U/L and 40.84?±?7.89?U/L. MDA, TC, TG and LDL-C decreased to 2.32?±?0.86?mmol/mg, 0.21?±?0.12?mmol/L, 0.96?±?0.31?mmol/L and 0.084?±?0.027?mmol/L. SOD, GSH-Px and GSH increased to 118.32?±?16.32?U/mg, 523.72?±?64.20?U/mg and 0.56?±?0.05?mg/g. Ratios of TGF-β1 and TNF-α decreased to 0.608?±?0.170 and 1.057?±?0.058, decorin increased to 2.182?±?0.129. Lachnospiraceae and Lactobacillus increased, Facklamia and Firmicutes decreased with GP pretreatment.

Discussion and conclusions: Intestinal microflora provides novel insight into the mechanisms of GP that may be used to treat ALF and intestinal microflora dysbiosis.     

Epigallocatechin-3-gallate counters cisplatin toxicity of rat testes

Context: Epigallocatechin-3-gallate (EG), the main active flavonoid in green tea, has well-known anti-inflammatory, antioxidant, and anti-apoptotic activities.

Objective: The EG protection against testicular injury induced by cisplatin was studied in Sprague–Dawley rats.

Materials and methods: Cisplatin (10?mg/kg, i.p) was given as a single injection to rats. EG was given at 40 and 80?mg/kg/day, i.p., for 5 days, starting the same day of cisplatin insult. Serum testosterone, and testicular malondialdehyde, total antioxidant status, nitric oxide, interleukin-6, interleukin-1β, cytochrome C, Bax/Bcl-2 ratio, and caspase-3 were measured. In addition, testicular histopathological examination and immunohistochemical expression of testicular tumour necrosis factor-α were evaluated.

Results: Cisplatin, compared to the control, significantly decreased serum testosterone (6.48?±?0.7 vs. 50.8?±?4.91?ng/10?mL), and testicular tissue antioxidant status (17.3?±?1.21 vs. 64.12?±?5.4?μmol/g), and significantly increased interleukin-6 (85.81?±?6.11 vs. 38.2?±?2.79?pg/100?mg), interleukin-1β (98.09?±?8.31 vs. 32.52?±?2.08?pg/100?mg), malondialdehyde (74.5?±?5.88 vs. 23.8?±?1.91?nmol/g), nitric oxide (104.98?±?8.5 vs. 52.68?±?5.12?nmol/100?mg), cytochrome C (5.97?±?0.33 vs. 1.6?±?0.99?ng/mg protein), Bax/Bcl-2 ratio (4.01?±?0.38 vs. 0.71?±?0.0), and caspase-3 (3.2?±?0.21 vs. 0.98?±?0.08?O.D. 405?nm) in rat testes. EG (40 and 80?mg/kg, respectively) caused significant increases of serum testosterone (33.9?±?2.89 and 47.88?±?4.4?ng/10?mL), and testicular antioxidant status (47.1?±?3.92 and 58.22?±?3.58?μmol/g), and significant decreases of interleukin-6 (57.39?±?4.2 and 48.18?±?3.98?pg/100?mg), interleukin-1β (65.12?±?5.88 and 41.96?±?3.51?pg/100?mg), malondialdehyde (42.3?±?3.9 and 28.67?±?2.49?nmol/g), nitric oxide (70.6?±?6.79 and 61.31?±?5.18?nmol/100?mg), cytochrome C (3.4?±?0.27 and 2.21?±?0.18?ng/mg protein), Bax/Bcl-2 ratio (1.49?±?0.14 and 1.1?±?0.09), and caspase-3 (2.1?±?0.17 and 1.48?±?0.13?O.D. 405?nm) in testes of cisplatin-treated rats. Additionally, both doses of EG significantly ameliorated the histopathological injury and reduced tumour necrosis factor-α expression in rat testes.

Conclusion: EG can afford testicular protection in cisplatin-challenged rats by its antioxidant, antinitrative, anti-inflammatory and antiapoptotic effects.     

Lipid-lowering property of Clausena anisum-olens in hypercholesterolemic rats

Context: Clausena anisum-olens (Blanco) Merr. (Rutaceae) is a medicinal shrub which has been reported to have various pharmacological uses. No study regarding the effects of C. anisum-olens on cholesterol-lowering has been reported.

Objective: The effects of the ethanol extract of C. anisum-olens leaves on the cholesterol level of hypercholesterolemic rats were evaluated.

Materials and methods: Acute oral toxicity of the extract (175, 550 and 2000?mg/kg) was determined using female Sprague-Dawley rats, as described in OECD 425 Main test guidelines. The lipid-lowering assay utilized 30 male Sprague-Dawley rats divided into five groups (A–E). Triton X-100 was administered to induce hypercholesterolemia. After hypercholesterolemia induction, oral treatment of Atorvastatin and crude ethanol extract was given daily to the treatment groups for 14 days. The total cholesterol, triglycerides, HDL and LDL were determined before induction, after induction, after first week of treatment and after second week of treatment.

Results: Acute oral toxicity showed the crude extract is nontoxic up to 2000?mg/kg. The lipid-lowering assay indicated reduction of serum cholesterol (87.21?±?5.10?mg/dL), triglycerides (58.09?±?4.10?mg/dL) and LDL (27.82?±?4.11?mg/dL) for 200?mg/kw extract. Reduction in serum cholesterol (74.72?±?3.64?mg/dL), triglycerides (52.79?±?2.98?mg/dL) and LDL (12.06?±?5.51?mg/dL) were observed for 400?mg/kg group. The result is comparable to Atorvastatin, which showed serum cholesterol (80.90?±?9.72?mg/dL), triglycerides (55.94?±?7.19?mg/dL) and LDL (22.09?±?7.60?mg/dL) reduction.

Discussion and conclusion: The crude extract of C. anisum-olens proved to be useful in lowering of cholesterol.     

Effects of rosmarinic acid on an experimental model of painful diabetic neuropathy in rats

Context: Diabetic neuropathic (DN) pain is one of the diabetes complications. Rosmarinic acid (RA), a natural phenol antioxidant, shows some biological activities, including anti-inflammatory, analgesic, and anti-diabetic effects.

Objectives: We investigated the efficacy of RA administration (10 and 30?mg/kg) on streptozotocin (STZ)-induced neuropathy in rats.

Material and methods: The animals received saline or RA (10 and 30?mg/kg, p.o.; once daily) for 8 weeks. DN was evaluated by the tail flick (TF) method, formalin test, and tactile allodynia. At the end, all rats were weighed and underwent plasma glucose measurement.

Results: There was an increase in licking time during both formalin test phases in diabetic animals (138.5?±?10.7 and 448.7?±?2.6?s) that was decreased by RA10?mg/kg (103.5?±?7.5 and 284.4?±?19?s) and RA 30?mg/kg (81.8?±?11 and 192.7?±?14?s). RA 30?mg/kg caused anti-nociception during the early phase in treated controls (52.1?±?6?s) than untreated controls (99.4?±?5.9?s). The TF latency in diabetics (2.9?±?0.1?s) was increased in RA10 and 30?mg/kg treated diabetics (5.3?±?0.4 and 6?±?0.86?s). The paw withdrawal threshold (PWT) of the diabetics (3.6?±?0.7?g) was increased after RA 10 and 30?mg/kg (13.8?±?0.3 and 14?±?0.4?g) treatment. RA did not induce a significant change in body weight and plasma glucose of rats.

Conclusion: RA showed efficacy in amelioration of some aspects of DN. Therefore, RA makes a good candidate for DN treatment in clinical studies.     

Antidepressant and anxiolytic activity of Lavandula officinalis aerial parts hydroalcoholic extract in scopolamine-treated rats

Context: Anxiety and depression are common in Alzheimer’s disease (AD). Despite some evidence, it is difficult to confirm Lavandula officinalis Chaix ex Vill (Lamiaceae) as an anxiolytic and antidepressant drug.

Objective: The effects of L. officinalis extract were studied in scopolamine-induced memory impairment, anxiety and depression-like behaviour.

Materials and methods: Male NMRI rats were divided into control, scopolamine alone-treated group received scopolamine (0.1?mg/kg) intraperitoneally (i.p.), daily and 30?min prior to performing behavioural testing on test day, for 12 continuous days and extract pretreated groups received aerial parts hydro alcoholic extract (i.p.) (100, 200 and 400?mg/kg), 30?min before each scopolamine injection. Memory impairment was assessed by Y-maze task, while, elevated plus maze and forced swimming test were used to measure anxiolytic and antidepressive-like activity.

Results: Spontaneous alternation percentage in Y maze is reduced by scopolamine (36.42?±?2.60) (p?≤?0.001), whereas lavender (200 and 400?mg/kg) enhanced it (83.12?±?5.20 and 95?±?11.08, respectively) (p?≤?0.05). Also, lavender pretreatment in 200 and 400?mg/kg enhanced time spent on the open arms (15.4?±?3.37 and 32.1?±?3.46, respectively) (p?≤?0.001). On the contrary, while immobility time was enhanced by scopolamine (296?±?4.70), 100, 200 and 400?mg/kg lavender reduced it (193.88?±?22.42, 73.3?±?8.25 and 35.2?±?4.22, respectively) in a dose-dependent manner (p?≤?0.001).

Discussion and conclusion: Lavender extracts improved scopolamine-induced memory impairment and also reduced anxiety and depression-like behaviour in a dose-dependent manner.     

Effects of rosmarinic acid on acetaminophen-induced hepatotoxicity in male Wistar rats

Context: Drug-induced liver injury is a significant worldwide clinical problem. Rosmarinic acid (RA), a natural phenol, has antioxidant effects.

Objective: The effects of RA against acetaminophen (N-acetyl-p-amino-phenol (APAP))-induced oxidative damage and hepatotoxicity in rats were investigated.

Materials and methods: Male Wistar rats were pretreated with RA (10, 50 and 100?mg/kg, i.g.) for one week. On day 7, rats received APAP (500?mg/kg, i.p.). Then aspartate aminotransferase (AST), alanine aminotransferase (ALT), albumin, total protein, malondialdehyde (MDA), glutathione (GSH), total antioxidant capacity (TAC), glutathione S-transferase (GST), cytochrome CYP450 and histopathological changes were determined.

Results: APAP-induced oxidative stress in liver by a significant increase in the level of MDA (7.6?±?0.21?nmol/mg) as well as a decrease in the contents of TAC (1.75?±?0.14?μmol/g), GSH (1.9?±?0.22?μmol/g) and GST) 3.2?±?0.28?U/mg). RA treatment decreased MDA (4.32?±?0.35?nmol/mg) but increased the contents of TAC (3.51?±?0.34?μmol/g), GSH (3.42?±?0.16?μmol/g) and GST (5.71?±?0.71?μmol/g) in APAP group. RA 100?mg/kg decreased ALT (91.5?±?1.5?U/L), AST (169?±?8.8?U/L) and CYP450 (3?±?0.2?nmol/min/mg) in APAP group. Histologically RA attenuated hepatic damage by decreasing necrosis, inflammation, and haemorrhage in liver sections of APAP group.

Discussion and conclusions: This is the first report that oral administration of RA dose-dependently elicited significant hepatoprotective effects in rats through inhibition of hepatic CYP2E1 activity and lipid peroxidation. RA-protected hepatic GSH and GST reserves and total tissue antioxidant capacity.     

Hesperidin,a citrus flavonoid,protects against l-methionine-induced hyperhomocysteinemia by abrogation of oxidative stress,endothelial dysfunction and neurotoxicity in Wistar rats

Context: Hesperidin (HSP), a flavanoglycone found in citrus fruits, has antioxidant, anti-inflammatory and neuroprotective properties.

Objective: This study evaluates the protective effect of HSP on l-methionine-induced hyperhomocysteinemia (HHcy) in rats.

Materials and methods: Male Wistar rats were randomly divided into seven groups as DMSO, l-methionine, HSP (25, 50 and 100?mg/kg), HSP-per se (100?mg/kg) and donepezil (0.1?mg/kg). HHcy was induced by oral administration of l-methionine (1.7?g/kg) for 32 days. From the 14^th day of study HSP (25, 50 and 100?mg/kg) and donepezil was administered orally to l-methionine-treated rats. Cognitive impairment induced by HHcy was determined using the Morris water maze (MWM) and Y-maze on video tracking system (28^th–32^nd day). Different biomarkers of HHcy in serum and brain and vascular reactivity were evaluated and histopathology (thoracic aorta and brain) was done.

Results: HSP (100?mg/kg) treatment in l-methionine-treated rats exhibited significant (p?p?l-methionine on acetylcholine-induced endothelial-dependent relaxation and increased serum nitrite and vascular nitric oxide bioavailability along with the restoration of histological aberrations.

Conclusion: HSP exerts a protective effect on HHcy by abrogating oxidative stress, ED and neurotoxicity.     

Effects of type 2 diabetes mellitus on the pharmacokinetics of berberine in rats

Context: Berberine is an active alkaloid isolated from Rhizoma coptidis [Coptis chinensis Franch. (Ranunculaceae)] that is widely used for the treatment of diabetes, hyperlipidemia and hypertension. However, the pharmacokinetics of berberine in normal rats and type 2 diabetes mellitus (T2DM) model rats are not clear.

Objective: This study compares the pharmacokinetics of berberine between normal and T2DM model rats.

Materials and methods: The T2DM model rats were fed with high fat diet for 4 weeks, induced by low-dose (30?mg/kg) streptozotocin for 72?h and validated by determining the peripheral blood glucose level. Rats were orally treated with berberine at a dose of 20?mg/kg and then berberine concentration in rat plasma was determined by employing a sensitive and rapid LC-MS/MS method.

Results: The significantly different pharmacokinetic behaviour of berberine was observed between normal and T2DM model rats. When compared with the normal group, C_max, t_1/2 and AUC_(0–t) of berberine were significantly increased in the model group (17.35?±?3.24 vs 34.41?±?4.25?μg/L; 3.95?±?1.27 vs 9.29?±?2.75?h; 151.21?±?23.96 vs 283.81?±?53.92?μg/h/L, respectively). In addition, oral clearance of berberine was significantly decreased in the model group (134.73?±?32.15 vs 62.55?±?16.34?L/h/kg).

Discussion and conclusion: In T2DM model rats, the pharmacokinetic behaviour of berberine was significantly altered, which indicated that berberine dosage should be modified in T2DM patients.     

Effects of glycyrrhizin on the pharmacokinetics of asiatic acid in rats and its potential mechanism

Context: Asiatic acid has been reported to possess a wide range of pharmacological activities.

Objective: This study investigates the effects of glycyrrhizin on the pharmacokinetics of asiatic acid in rats and its potential mechanism.

Materials and methods: The pharmacokinetics of orally administered asiatic acid (20?mg/kg) with or without glycyrrhizin pretreatment (100?mg/kg/day for seven days) were investigated using a LC–MS method. Additionally, the Caco-2 cell transwell model and rat liver microsome incubation systems were used to investigate the potential mechanism of glycyrrhizin’s effects on the pharmacokinetics of asiatic acid.

Results: The results showed that the C_max (221.33?±?21.06 vs. 324.67?±?28.64?ng/mL), AUC_0–inf (496.12?±?109.31 vs. 749.15?±?163.95?μg·h/L) and the t_1/2 (1.21?±?0.27 vs. 2.04?±?0.32?h) of asiatic acid decreased significantly (p?p?Discussion and conclusions: In conclusion, these results indicated that glycyrrhizin could decrease the system exposure of asiatic acid, possibly by inducing the activity of P-gp or CYP450 enzyme.     

Prunus mume leaf extract lowers blood glucose level in diabetic mice

Context Diabetes is a common metabolic disease with long-term complications. Prunus mume Sieb. et Zucc. (Rosaceae) fruits have shown to ameliorate glucose intolerance. However, the antidiabetic effects of P. mume leaves have not been investigated.

Objective This study evaluated the effects of P. mume leaf 70% ethanol extract (PMLE) on alleviating diabetes in vivo and in vitro.

Materials and methods PMLE was fractionated into n-hexane, dichloromethane (CH₂Cl₂), ethyl acetate (EtOAc), n-butanol (BuOH) and water. Polyphenol and flavonoid contents in PMLE fractions were determined using Folin–Ciocalteu reagent and the aluminium chloride colorimetric method, respectively. We evaluated α-glucosidase inhibition using a microplate reader at 400?nm. Adipocyte differentiation by lipid accumulation was measured using Nile Red staining. Male imprinting control region (ICR) mice were injected with streptozotocin (STZ, 100?mg/kg, i.p.). High-fat diets were provided for three weeks prior to PMLE treatments to induce type 2 diabetes. PMLE (0, 5, 25 or 50?mg/kg) was administrated for four weeks with high-fat diets.

Results The EtOAc fraction of PMLE inhibited α-glucosidase activity (IC₅₀?=?68.2?μg/mL) and contained 883.5?±?14.9?mg/g of polyphenols and 820.1?±?7.7?mg/g of flavonoids. The 50?mg/kg PMLE supplement reduced 40% of blood glucose level compared to obese/diabetes mice. Obese/diabetic mice treated with 50?mg/kg PMLE showed a lower level of triacylglycerol (320.7?±?20.73?mg/dL) compared to obese/diabetes mice (494.9?±?14.80?mg/dL).

Conclusion The data demonstrate that P. mume leaves exert antidiabetic effects that may be attributable to high concentrations of polyphenols and flavonoids.     

Effects of polysaccharide from Physalis alkekengi var. francheti on liver injury and intestinal microflora in type-2 diabetic mice

Context: Diabetic liver injury is a serious diabetic complication. The alterations of intestinal microbiota play an important role in induction and promotion of liver injury progression. Physalis alkekengi L. var. francheti (Mast.) Makino (Solanaceae) has been used as a water decoction for treating diabetes.

Objective: To study the effects of a polysaccharide (PPSB) from Physalis alkekengi var. francheti on liver injury and intestinal microflora in type-2 diabetic mice.

Materials and methods: Streptozotocin (160?mg/kg) was injected i.p. for 3?days to build model. The diabetic mice were randomly divided into four groups together with control group (10 mice in each group). The doses of PPSB were 50 and 100?mg/kg, respectively. After 5 weeks administration, level of blood glucose, ALT and AST were measured. Alterations of intestinal microflora, and protein expression of TGF-β1, TNF-α and DCN were detected.

Results: Level of blood glucose decreased from (25.38?±?2.21) mmol/L to (18.01?±?2.53) mmol/L, ALT and AST decreased to (24.67?±?4.86) U/L and (30.84?±?7.50) U/L in PPSB-H group. Lactobacillus, Clostridium butyricum, and Bacteroides increased remarkably with increasing concentration of PPSB, but Enterobacter was inhibited. The relative expression of TGF-β1 and TNF-α decreased to (0.70?±?0.17) and (0.39?±?0.06), and the expression of DCN increased to (0.65?±?0.13).

Discussion and conclusions: Probiotics have been promoted by PPSB, and protein expressions have been modulated in the progression of liver injury. PPSB could be used as a natural agent for treating diabetic liver injury and intestinal microflora imbalance.     

Bioactive peptide carnosin protects against lead acetate-induced hepatotoxicity by abrogation of oxidative stress in rats

Context Oxidative stress is a common mechanism of liver injury. Carnosine is a dipeptide having strong antioxidant effects.

Objectives We investigated the effects of carnosine on lead-induced hepatotoxicity and oxidative stress in rats.

Materials and methods Animals received an aqueous solution of lead acetate (500?mg Pb/L in the drinking water) and/or daily oral gavage of carnosine (10?mg/kg) for 8 weeks. Rats were then weighed and used for the biochemical (commercial kits), molecular (standard chemical methods) and histological (microscopic) evaluations.

Results Lead-induced oxidative stress in liver tissue was indicated by a significant increase in the level of malondialdehyde (MDA) (8.25?±?0.15?nmol/mg) as well as decrease in the level of total antioxidant capacity (TAC) (1.72?±?0.25?μmol/g) and total thiol (SH) groups) 1.9?±?0.22?μmol/g). Carnosine treatment decreased MDA (4?±?0.08?nmol/mg), whereas it increased the contents of total thiol (3.25?±?0.04?μmol/g) and TAC (3.44?±?0.32?μmol/g) in the lead group. Carnosine also prevented the decreased body weight (p?<?0.001), albumin (p?<?0.05) and total protein levels (p?<?0.001) and increased liver weight (p?<?0.05) and activates of hepatic enzymes (p’s?<?0.001) (alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and lactate dehydrogenase) in the lead group. Furthermore, histopathological study showed that carnosine attenuates liver damage by decreasing necrosis and infiltration of inflammatory cells.

Conclusion Carnosine prevented lead-induced hepatotoxicity, indicated by molecular, biochemical and histopathological analyses through inhibiting lipid peroxidation and enhancing antioxidant defence systems. Therefore, carnosine makes a good candidate to protect against the deleterious effect of chronic lead intoxication.