Investigation of the influence of glycyrrhizin on the pharmacokinetics of celastrol in rats using LC-MS and its potential mechanism

1.?The aim of this study was to investigate the effects of glycyrrhizin on the pharmacokinetics of celastrol in rats.

2.?Twelve male Sprague–Dawley rats were randomly assigned to two groups: control group and test group. Test group was pretreated with glycyrrhizin at a dose of 100?mg/kg/day for 10 days, and then the two groups were orally administered with celastrol at a dose of 1?mg/kg. The concentration of celastrol was determined using a sensitive and reliable LC-MS method.

3.?The results showed that glycyrrhizin could significantly decrease the plasma concentration (from 64.36?ng/mL to 38.42?ng/mL) and AUC_0?t (from 705.39 to 403.43?μg·h/L) of celastrol in rats. To investigate its potential mechanism, the effects of glycyrrhizin on the transport and metabolic stability of celastrol were investigated using Caco-2 cell monolayer transwell model and rat liver microsome incubation systems. The Caco-2 cell monolayer transwell experiments indicated that glycyrrhizin could increase the efflux ratio of celastrol (4.02 versus 6.51). However, the rat liver microsome incubation experiments showed that glycyrrhizin could significantly increase the intrinsic clearance rate of celastrol from 20.3?±?3.37 to 38.8?±?4.18?μL/min/mg protein.

4.?In conclusion, these results indicated that the herb–drug interaction between glycyrrhizin and celastrol might occur when they were coadministered.     

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.     

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.     

An evaluation of the anti-inflammatory,antipyretic and analgesic effects of hydroethanol leaf extract of Albizia zygia in animal models

Context: The leaves of Albizia zygia (DC.) J.F. Macbr. (Leguminosae-Mimosoideae) are used in Ghanaian traditional medicine for the treatment of pain, inflammatory disorders and fever (including malaria).

Objectives: The present study evaluated the anti-inflammatory, antipyretic and analgesic effects of the hydroethanol leaf extract of Albizia zygia (AZE) in animal models.

Materials and methods: The anti-inflammatory and antipyretic effects of AZE were examined in the carrageenan-induced foot oedema model and the baker’s yeast-induced pyrexia test respectively. The analgesic effect and possible mechanisms of action were also assessed in the formalin test.

Results: AZE (30–300?mg/kg, p.o.), either preemptively or curatively, significantly inhibited carrageenan-induced foot edema in 7-day-old chicks (ED₅₀ values; preemptive: 232.9?±?53.33?mg/kg; curative: 539.2?±?138.28?mg/kg). Similarly, the NSAID diclofenac (10–100?mg/kg, i.p.) significantly reduced the oedema in both preemptive (ED₅₀: 21.16?±?4.07?mg/kg) and curative (ED₅₀: 44.28?±?5.75?mg/kg) treatments. The extract (30–300?mg/kg, p.o.) as well as paracetamol (150?mg/kg, p.o.) also showed significant antipyretic activity in the baker’s yeast-induced pyrexia test (ED₅₀ of AZE: 282.5?±?96.55?mg/kg). AZE and morphine (1–10?mg/kg, i.p.; positive control), exhibited significant analgesic activity in the formalin test. The analgesic effect was partly or wholly reversed by the systemic administration of naloxone, theophylline and atropine.

Conclusion: The results suggest that AZE possesses anti-inflammatory, antipyretic and analgesic properties, which justifies its traditional use. Also, the results show the involvement of the opioidergic, adenosinergic and the muscarinic cholinergic pathways in the analgesic effects of AZE.     

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.     

Hematological and lipid profile evaluation of a hexane fraction of Costus afer leaves in arthritic rats

Abstract

Context: Costus afer Ker Gawl. (Costaceae) is an ethnomedical plant used as therapy against inflammatory disorders.

Objective: The objective of this study was to evaluate the hematological and lipid profile analysis of hexane fraction of C. afer leaves (CAHLF) in arthritic rats.

Materials and methods: Male albino rats were randomly distributed into seven groups of six rats each. Rats were induced with arthritis using formaldehyde and Complete Freund’s Adjuvant (CFA) for 7 and 21?d, respectively. The animals were administered orally with 50, 100, and 250?mg/kg CAHLF, 10?mg/kg diclofenac and prednisolone, 0.9% NaCl (control), and 0.9% NaCl (normal). At the end of treatment periods, blood samples were withdrawn and subjected to hematological and biochemical analysis using auto-analyzer and spectrophotometric methods.

Results: Hematological analysis revealed that in formaldehyde- and CFA-induced arthritic rat models, 250?mg/kg CAHLF-treated groups had significantly reduced (p?<?0.05) hematocrit counts (HC) (30.98?±?1.59% and 33.55?±?1.10%), white blood cell counts (WBC) (5.50?±?0.35 and 4.15?±?0.82?×?10⁹/L), and platelet counts (PC) (401.50?±?48.94 and 246.33?±?5.54?×?10⁹/L) compared with control HC (46.90?±?1.92 and 41.88?±?2.19%), WBC (11.09?±?0.26 and 7.37?±?0.34?×?10⁹/L), and PC (783.67?±?59.51 and 593.83?±?36.3?×?10⁹/L). Furthermore, blood analysis showed that CAHLF-treated groups had reduced total cholesterol, low-density lipoprotein cholesterol, and triglycerides while they had an elevated high-density lipoprotein compared with the control group.

Discussion and conclusion: Findings from this study indicated that CAHLF could possess immunomodulatory and hypolipidemic properties in arthritic rats. CAHLF could be considered as a source of biopharmaceutical agents in anti-arthritis drug discovery process.     

Antidiabetic,antilipidemic, and antioxidant activities of Gouania longipetala methanol leaf extract in alloxan-induced diabetic rats

Abstract

Context: Gouania longipetala Hemsl. (Rhamnaceae) is used in folkloric medicine for treating diabetes mellitus and its associated symptoms.

Objective: This study evaluated the antidiabetic antilipidemic and antioxidant activities of the plant methanol leaf extract.

Materials and methods: Diabetes was induced in rats by intraperitoneal injection of alloxan monohydrate (160?mg/kg). Three test doses (50, 100, and 150?mg/kg) of G. longipetala extract (GLE) were administered orally and the effects were compared with glibenclamide (2?mg/kg). The effect of GLE on hyperglycemia and sub-acute study for 21?d were carried out using its effect on fasting blood sugar (FBS) level. Serum biochemistry and antioxidant activity were evaluated. Histopathological evaluation of the pancreas was also done.

Results: The LD₅₀ of G. longipetala was found to be >4000?mg/kg. The extract significantly (p?<?0.0001) decreased the FBS levels of treated rats from 16.2?±?2.03 to 6.5?±?1.52?mM/L at 150?mg/kg within 24?h. The extract decreased FBS levels of rats by 62.0, 74.8, and 75.0% on day 21 at 50, 100, and 150?mg/kg, respectively. GLE reduced the level of malondiadehyde from 23.0?±?1.34?to 10.3?±?0.43?mg/dL, increased superoxide dismutase activities from 2.97?±?0.34 to 5.80?±?0.53?IU/L at 150?mg/kg, and improved the serum lipid profile of treated rats. GLE also caused restoration of the altered histopathological changes of the pancreas.

Discussion and conclusion: Gouania longipetala demonstrated significant antidiabetic, antilipidemic, and antioxidant activities that may be due to its multiple effects involving both pancreatic and extra-pancreatic mechanisms.     

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.     

Effects of triptolide on pharmacokinetics of amlodipine in rats by using LC–MS/MS

Context: Triptolide and amlodipine are often simultaneously used for reducing urine protein excretion after renal transplantation in China clinics.

Objective: This study investigated the effects of triptolide on the pharmacokinetics of amlodipine in male Sprague–Dawley rats.

Materials and methods: The pharmacokinetics of amlodipine (1?mg/kg) with or without triptolide pre-treatment (2?mg/kg/day for seven?days) were investigated using a sensitive and reliable LC–MS/MS method. Additionally, the inhibitory effects of triptolide on the metabolic stability of amlodipine were investigated using rat liver microsome incubation systems.

Results: The results indicated that when the rats were pre-treated with triptolide, the C_max of amlodipine increased from 13.78?±?3.57 to 19.96?±?4.56?ng/mL (p?T_max increased from 4.04?±?1.15 to 5.89?±?1.64?h (p?AUC_0–t increased by approximately 104% (p?p?Conclusions: In conclusion, these results indicated that triptolide could affect the pharmacokinetics of amlodipine, possibly by inhibiting the metabolism of amlodipine in rat liver when they are co-administered.     

Effects of berberine on the pharmacokinetics of losartan and its metabolite EXP3174 in rats and its mechanism

Context: Losartan and berberine (BBR) are often simultaneously used for the treatment of senile diabetic nephropathy in clinics. However, the potential herb–drug interaction between losartan and BBR is unknown.

Objective: This study investigates the influence of BBR on the pharmacokinetics of losartan and EXP3174, and investigates the effects of BBR on the metabolic stability of losartan.

Materials and methods: The pharmacokinetic profiles losartan and EXP3174 of orally administered losartan (10?mg/kg) with and without pretreatment with BBR (20?mg/kg) within 24?h were determined in Sprague-Dawley rats. The inhibitory effects of BBR on the metabolic stability of losartan were investigated using rat liver microsomes.

Results: The C_max (1.26?±?0.37 versus 1.96?±?0.45?mg/L) and the AUC_(0–t) (8.25?±?0.89 versus 12.70?±?1.42?mg h/L) of losartan were significantly (p?<?0.05) increased by BBR compared to the control, while the C_max (0.97?±?0.15 versus 0.77?±?0.06?mg/L) of EXP3174 was significantly decreased compared to the control (p?<?0.05). The T_max of losartan was prolonged from 0.41?±?0.12 to 0.52?±?0.18?h, but the difference was not significant. However, the T_max of EXP3174 was decreased significantly (p?<?0.05) from 8.14?±?0.36 to 3.33?±?0.28?h. The metabolic stability of losartan was increased from 37.4 to 59.6?min.

Discussion and conclusion: We infer that BBR might increase the plasma concentration of losartan and decrease the concentration of EXP3174 through inhibiting the activity of CYP3A4 or CYP2C9.     

Hydroalcoholic extract of Myrtus communis can alter anxiety and sleep parameters: a behavioural and EEG sleep pattern study in mice and rats

Context: Myrtus communis L. (Myrtaceae), myrtle, is an evergreen shrub with strong antibacterial, anti-inflammatory, antihyperglycemic and antioxidant activities. Also, it is used as a sedative-hypnotic plant in Iranian traditional medicine.

Objective: This study evaluates the effect of 80% ethanolic extract of M. communis leaves on sleep and anxiety in mice and rats.

Materials and methods: Male NMRI mice were subjected to open field, righting reflex, grip strength and pentylentetrazole-induced seizure tests. Male Wistar rats were used to evaluate the alterations in rapid eye movement (REM) and non-REM (NREM) sleep. They were treated with 25–400?mg/kg doses of the extract intraperitoneally.

Results: The applied doses (50–200?mg/kg) of M. communis extract increased vertical (ED_50?=_?40.2?±?6.6?mg/kg) and vertical and horizontal activity (ED_50?=_?251?±?55?mg/kg), while treatment with 200 and 400?mg/kg attenuated muscle tone significantly compared to vehicle treated animals (p?<?0.001 for all) in a dose-independent manner. Also, a significant hypnotic and not anticonvulsant effect was observed when animals were treated with 200?mg/kg of the extract (p?<?0.01). In this regard, electroencephalography results showed that REM sleep time was decreased (2.4?±?0.5%), while total and NREM sleep times were increased significantly compared to the control group of mice (82.5?±?7.6%).

Discussion and conclusion: The data show the anxiolytic and muscle relaxant effect of the extract without anticonvulsant activities. The anxiolytic, myorelaxant and hypnotic effects without effect on seizure threshold are in line with the effect of a alpha 2 GABA receptor agonist.     

GC-MS analysis and hepatoprotective activity of the n-hexane extract of Acrocarpus fraxinifolius leaves against paracetamol-induced hepatotoxicity in male albino rats

Context: In Egypt, the burden of liver diseases is exceptionally high.

Objective: To investigate the components of the n-hexane extract of Acrocarpus fraxinifolius Arn. (Leguminosae) and its hepatoprotective activity against paracetamol (APAP)-induced hepatotoxicity in rats.

Material and methods: TRACE GC ultra gas chromatogaphic spectrometry was used for extract analysis. Thirty albino rats were divided into six groups (five rats in each). Group 1 was the healthy control; Groups 2 and 3 were healthy treated groups (250 and 500?mg/kg b.w. of the extract, respectively) for seven days. Group 4 was hepatotoxicity control (APAP intoxicated group). Groups 5 and 6 received APAP?+?extract 250 and APAP?+?extract 500, respectively.

Results: Chromatographic analysis revealed the presence of 36 components. Major compounds were α-tocopherol (18.23%), labda-8 (20)-13-dien-15-oic acid (13.15%), lupeol (11.93%), phytol (10.95%) and squalene (7.19%). In the acute oral toxicity study, the mortality rates and behavioural signs of toxicity were zero in all groups (doses from 0 to 5?g/kg b.w. of A. fraxinifolius). LD₅₀ was found to be greater than 5?g/kg of the extract. Only the high dose (500?mg/kg b.w.) of extract significantly alleviated the liver relative weight (4.01?±?0.06) and biomarkers, as serum aspartate aminotransferase (62.87?±?1.41), alanine aminotransferase (46.74?±?1.45), alkaline phosphatase (65.96?±?0.74), lipid profiles (180.39?±?3.51), bilirubin profiles (2.30?±?0.06) and hepatic lipid peroxidation (114.20?±?2.06), and increased body weight (11.58?±?0.20), serum protein profile (11.09?±?0.46) and hepatic total antioxidant capacity (23.78?±?0.66) in APAP-induced hepatotoxicity in rats.

Conclusion: Our study proves the antihepatotoxic/antioxidant efficacies of A. fraxinifolius hexane extract.     

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.     

The effects of triptolide on the pharmacokinetics of sorafenib in rats and its potential mechanism

Context: Combining sorafenib with triptolide could inhibit tumour growth with greater efficacy than single-agent treatment. However, their herb–drug interaction remains unknown.

Objective: This study investigates the herb–drug interaction between triptolide and sorafenib.

Materials and methods: The effects of triptolide (10?mg/kg) on the pharmacokinetics of different doses of sorafenib (20, 50 and 100?mg/kg) in rats, and blood samples were collected within 48?h and evaluated using LC-MS/MS. The effects of triptolide on the absorption and metabolism of sorafenib were also investigated using Caco-2 cell monolayer model and rat liver microsome incubation systems.

Results: The results showed that the C_max (low dose: 72.38?±?8.76 versus 49.15?±?5.46?ng/mL; medium dose: 178.65?±?21.05 versus 109.31?±?14.17?ng/mL; high dose: 332.81?±?29.38 versus 230.86?±?9.68?ng/mL) of sorafenib at different doses increased significantly with the pretreatment of triptolide, and while the oral clearance rate of sorafenib decreased. The t_1/2 of sorafenib increased significant (p?Discussion and conclusions: These results indicated that triptolide could change the pharmacokinetic profiles of sorafenib in rats; these effects might be exerted via decreasing the intrinsic clearance rate of sorafenib in rat liver.     

Determination of cepharanthine in rat plasma by LC–MS/MS and its application to a pharmacokinetic study

Context: Cepharanthine (CPA) has been reported to possess a wide range of pharmacological activities.

Objective: This study investigates the pharmacokinetic characteristics after oral or intravenous administration of CPA by using a sensitive and rapid LC–MS/MS method.

Materials and methods: A sensitive and rapid LC–MS/MS method was developed for the determination of CPA in Sprague–Dawley rat plasma. Twelve rats were equally randomized into two groups, including the intravenous group (1?mg/kg) and the oral group (10?mg/kg). Blood samples (250?μL) were collected at designated time points and determined using this method. The pharmacokinetic parameters were calculated.

Results: The calibration curve was linear within the range of 0.1–200?ng/mL (r?=?0.999) with the lower limit of quantification at 0.1?ng/mL. After 1?mg/kg intravenous injection, the concentration of CPA reached a maximum of 153.17?±?16.18?ng/mL and the t_1/2 was 6.76?±?1.21?h. After oral administration of 10?mg/kg of CPA, CPA was not readily absorbed and reached C_max 46.89?±?5.25?ng/mL at approximately 2.67?h. The t_1/2 was 11.02?±?1.32?h. The absolute bioavailability of CPA by oral route was 5.65?±?0.35%, and the bioavailability was poor.

Discussion and conclusions: The results indicate that the bioavailability of CPA was poor in rats, and further research should be conducted to investigate the reason for its poor bioavailability and address this problem.     

Antiobesity and antihyperglycaemic effects of Adiantum capillus-veneris extracts: in vitro and in vivo evaluations

Context: Adiantum capillus-veneris L. (Adiantaceae) hypocholesterolemic activity is therapeutically praised.

Objectives: Pharmacological modulation of pancreatic triacylglycerol lipase (PL) and α-amylase/α-glucosidase by A. capillus-veneris are evaluated.

Materials and methods: Using positive controls (acarbose, orlistat, guar gum, atorvastatin, glipizide and metformin) as appropriate, crude aqueous extracts (AEs) of A. capillus-veneris aerial parts were tested via a combination of in vitro enzymatic (0.24–100?mg/mL), acute in vivo carbohydrate tolerance tests (125, 250 or 500?mg/kg body weight [b.wt]) and chronic in vivo studies (500?mg/kg b.wt) in high cholesterol diet (HCD) fed Wistar rats.

Results: Like acarbose, A. capillus-veneris as well as chlorogenic acid, with respective IC₅₀ values (mg/mL) of 0.8?±?0.0 and 0.2?±?0.0, were identified as in vitro potent dual inhibitors of α-amylase/α-glucosidase. Unlike guar gum, A. capillus-veneris had no glucose diffusion hindrance capacity. Equivalent to orlistat, A. capillus-veneris and its phytoconstituents inhibited PL in vitro with an ascending order of PL- IC₅₀ values (μg/mL): ferulic acid; 0.48?±?0.06?A. capillus-veneris; 1600?±?100. Incomparable to acarbose or metformin and glipizide, A. capillus-veneris (125, 250 and 500?mg/kg b.wt) lacked antihyperglycaemic efficacies in acute starch- or glucose-evoked postprandial hyperglycaemia increments in normoglycaemic overnight fasting rats. Superior to atorvastatin; A. capillus-veneris exerted significant antiobesity (p?p?Discussion and conclusion: A. capillus-veneris, modulating pancreatic digestive enzymes, may be advocated as a combinatorial diabesity prevention/phytotherapy agent.     

Effects of Ginkgo leaf tablets on the pharmacokinetics of losartan and its metabolite EXP3174 in rats and its mechanism

Context: Ginkgo leaf tablets (GLTs) and losartan are often simultaneously used for the treatment of hypertension in Chinese clinics. However, the herb–drug interaction between GLT and losartan is still unknown.

Objective: This study investigates the effects of GLT on the pharmacokinetics of losartan and its metabolite EXP3174 in rats and its potential mechanism.

Materials and methods: The pharmacokinetic profiles of losartan and EXP3174 of orally administered losartan (10?mg/kg) with or without GLT pretreatment (80?mg/kg/day for 10?days) in Sprague–Dawley rats were determined. In vitro, the effects of GLT on the metabolic stability of losartan were investigated with rat liver microsomes.

Results: The C_max (1.22?±?0.25 vs 1.85?±?0.37?μg/mL) and the AUC_(0–t) (6.99?±?1.05 vs 11.94?±?1.79?mg·h/L) of losartan increased significantly (p?C_max (1.05?±?0.19 vs 0.72?±?0.12?μg/mL) of EXP3174 decreased significantly (p?t_1/2 of losartan was prolonged significantly from 3.94?±?0.62 to 4.75?±?0.52?h (p?Discussion and conclusions: The results indicate that GLT might increase the plasma concentration of losartan and decrease the concentration of EXP3174 through inhibiting the metabolism of losartan.     

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.     

Antioxidant properties of Ferulago angulata and its hepatoprotective effect against N-nitrosodimethylamine-induced oxidative stress in rats

Context: Ferulago angulata (Schlecht.) Boiss. (Apiaceae) (FASB) is used to treat liver diseases and has been used both as food and therapeutics by many cultures for thousands of years because of the natural antioxidant compounds.

Objective: This study determines antioxidant properties of FASB flowers, the levels of minerals and vitamins, and also, evaluates the hepatoprotective effect of flowers against N-nitrosodimethylamine (NDMA) induced on liver tissue by assessing antioxidant enzymes and histopathological parameters in Wistar albino rats.

Materials and methods: In the study, the rats were divided into six groups of ten. Control, untreated animals were given 0.9% NaCl. Rats were intraperitoneally given NDMA (10?mg/kg) for the first 7 days. FASB methanol extract (150 and 300?mg/kg) was administered orally for 21 days.

Results: α-Tocopherol, retinol, ascorbic acid, total antioxidant activity, phenolic and flavonoid contents of FASB were 0.70?±?0.13, 0.29?±?0.03?μg/g, 139.32?±?7.06?μg/100?g, 171.61?±?6.05?mM ascorbic acid/g, 90.47?±?4.11?mg GA/g and 37.39?±?2.85?mg QE/g. DPPH and hydroxyl radical scavenging activity was obtained IC₅₀ 67.34?±?4.14 and 64.87?±?4.68?μg/mL, respectively.

Discussion and conclusion: The results of the study indicated that FASB flowers contain high levels of vitamins, minerals, total antioxidant activity, phenolics and flavonoids. Due to the positive effect on significant changes in antioxidant enzymes of liver tissue and histopathological examination, it is thought that the plant could be used as a hepatoprotective.     

Beneficial effect of Citrus limon peel aqueous methanol extract on experimentally induced urolithic rats

Context: Citrus limon (L.) Burm.f. (Rutaceace) is a commonly available fruit variety with high medicinal and industrial values.

Objective: Lemon peel (LP) extract was studied as a potent preventive and curative agent for experimentally induced hyperoxaluric rats.

Materials and methods: Gas chromatography–mass spectrometry (GC–MS) analyses and toxicity study were performed for aqueous methanol LP extract. Twenty-four Wistar rats were segregated into four groups. Group 1: Control; Group 2: Urolithic (ethylene glycol (EG) – 0.75%); Group 3: Preventive study (EG?+?LP extract administration from 0th to 7th week); Group 4: Curative study (EG?+?LP extract administration from 4th to 7th week). Animals received LP extract daily by oral administration (100?mg/kg body weight) for 7 weeks.

Results and discussion: GC–MS analyses revealed that compound 6 was abundant in the LP extract (32%) followed by compound 1 (～21%). The LD₅₀ value of LP extract was found to be >5000?mg/kg of body weight. Urolithic rats showed significantly higher urinary calcium and oxalate (4.47?±?0.44 and 18.86?±?0.55?mg/24 h, respectively) excretion compared with control and experimental rats. Renal function parameters like urea (84?±?8.5 and 96.1?±?3.6?mg/dL), creatinine (1.92?±?0.27 and 1.52?±?0.22?mg/dL), and urinary protein (2.03?±?0.02 and 2.13?±?0.16?mg/24 h) were also reduced by LP extract (p?<?0.001) and corroborated with tissue analyses (SOD, catalase, and MDA levels) and histological studies in normal and experimental animals. Immunohistochemical staining of THP and NF-κB in urolithic animals showed elevated expression than the control, while LP extract suppressed the expression of these proteins.

Conclusion: In conclusion, lemon peel is effective in curing kidney stone disease and also can be used to prevent the disease and its recurrence.