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 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.     

The efficacy of pregabalin for treating pain associated with diabetic peripheral neuropathy in subjects with type 1 or type 2 diabetes mellitus

Objective: The objective of this study was to compare the efficacy and safety of pregabalin for painful diabetic peripheral neuropathy (pDPN) in subjects with type 1 (T1DM) or 2 diabetes mellitus (T2DM).

Methods: Pooled data from 10 randomized clinical trials (pregabalin-treated T1DM and T2DM subjects with pDPN) were analyzed for change from baseline (CFB) scores (pain and sleep disturbance) using mixed model repeated measures (MMRM) through Week 12 and last observation carried forward (LOCF). Adverse events (AEs) were recorded.

Results: Pregabalin-treated (T1DM 156 [8.7%]; T2DM 1632 [91.3%]) and placebo subjects (T1DM 92 [9.6%]; T2DM 868 [90.4%]) had comparable baseline demographic characteristics between treatment groups within the same diabetes type. T2DM (vs. T1DM) subjects were ～10 years older. With pregabalin and placebo, respectively, mean?±?SD baseline pain (T1DM: 6.2?±?1.4 and 6.5?±?1.6; T2DM: 6.5?±?1.5 and 6.4?±?1.5) and sleep scores (T1DM: 5.2?±?2.4 and 5.2?±?2.7; T2DM: 5.3?±?2.5 and 5.1?±?2.5) were comparable. Using MMRM, mean CFB treatment differences (pregabalin minus placebo) were significantly different for pain and sleep with either diabetes types (all weeks p?<?.05). With LOCF, pregabalin’s odds ratios (ORs) of achieving 30% pain reduction were similar with T2DM (OR, 1.91, 95% CI [1.61, 2.27]) and T1DM (2.01 [1.18, 3.44]) (both p ≤ .01). Pregabalin’s ORs of 30% improvement in sleep quality were 1.81 (95% CI, 1.06, 3.09) with T1DM and 2.01 (1.69, 2.39) with T2DM (both p?<?.05). AEs were consistent with the known safety profile of pregabalin.

Conclusions: Pregabalin significantly improved pain and sleep quality, without a clinically meaningful difference between diabetes types.

ClinicalTrial.gov registration: NCT00156078, NCT00159679, NCT00143156, NCT00553475.     

Effects of diclofenac on the pharmacokinetics of celastrol in rats and its transport

Context: Diclofenac and celastrol are always used together for the treatment of rheumatoid arthritis; the herb–drug interaction potential between diclofenac and celastrol is still unknown.

Objective: This study investigates the effects of diclofenac on the pharmacokinetics of celastrol in rats.

Materials and methods: Twelve male Sprague-Dawley rats were divided into two groups and received celastrol (1?mg/kg) or both celastrol (1?mg/kg) and diclofenac (10?mg/kg) by oral gavage, and blood samples were collected via the oculi chorioideae vein and determined using the LC-MS method developed in this study. Additionally, the effects of diclofenac on the transport of celastrol were investigated using a Caco-2 cell transwell model.

Results: Diclofenac could significantly (p?C_max (from 66.93?±?10.28 to 41.25?±?8.06?ng/mL) and AUC_0-t (from 765.84?±?163.61 to 451.33?±?110.88?μg?×?h/L) of celastrol in rats. The efflux ratio of celastrol increased significantly (p?Discussion and conclusion: These results indicated that diclofenac could decrease the system exposure of celastrol in rats when they are co-administered, and these effects might be exerted via decreasing its absorption in intestine.     

Influence of andrographolide on the pharmacokinetics of warfarin in rats

Context: Andrographolide and warfarin are often used together in clinics in China. However, the herb-drug interaction between andrographolide and warfarin is still unknown.

Objective: This study investigates the herb-drug interaction between andrographolide and warfarin in vivo and in vitro.

Materials and methods: A sensitive and reliable LC-MS/MS method was developed for the determination of warfarin in male Sprague-Dawley rats plasma, and then the pharmacokinetics of orally administered warfarin (0.5?mg/kg) with or without andrographolide (30?mg/kg/day for 7?days) pretreatment was investigated. In addition, Sprague-Dawley rat liver microsomes incubation systems were used to support the in vivo pharmacokinetic data and investigate its potential mechanism.

Results: The method validation results showed that a sensitive and reliable LC-MS/MS method was developed for the determination of warfarin in rat plasma samples. The pharmacokinetic results indicated that co-administration of andrographolide could increase the systemic exposure of warfarin significantly, including area under the curve (118.92?±?18.08 vs. 60.58?±?9.46?μg?×?h/mL), maximum plasma concentration (3.32?±?0.41 vs. 2.35?±?0.25?μg/mL) and t_1/2 (22.73?±?3.28 vs. 14.27?±?2.67?h). Additionally, the metabolic stability of warfarin increased from 23.5?±?4.7 to 38.7?±?6.1?min with the pretreatment of andrographolide, and the difference was significant (p?Discussion and conclusion: In conclusion, andrographolide could increase the systemic exposure of warfarin in rats when andrographolide and warfarin were co-administered, and possibly by slowing down the metabolism of warfarin in rat liver by inhibiting the activity of CYP3A4 or CYP2C9.     

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.     

Effects of Danshen tablets on pharmacokinetics of atorvastatin calcium in rats and its potential mechanism

Context: Danshen tablets (DST), an effective traditional Chinese multi-herbal formula, are often combined with atorvastatin calcium (AC) for treating coronary heart disease in the clinic.

Objective: This study investigated the effects of DST on the pharmacokinetics of AC and the potential mechanism.

Materials and methods: The pharmacokinetics of AC (1?mg/kg) with or without pretreatment of DST (100?mg/kg) were investigated using LC-MS/MS. The effects of DST (50?μg/mL) on the metabolic stability of AC were also investigated using rat liver microsome incubation systems.

Results: The results indicated that C_max (23.87?±?4.27 vs. 38.94?±?5.32?ng/mL), AUC_(0–t) (41.01?±?11.32 vs. 77.28?±?12.92?ng h/mL), and t_1/2 (1.91?±?0.18 vs. 2.74?±?0.23?h) decreased significantly (p?t_1/2) of AC was also decreased (25.7?±?5.2 vs. 42.5?±?6.1) with the pretreatment of DST.

Discussion and conclusions: This study indicated that the main components in DST could accelerate the metabolism of AC in rat liver microsomes and change the pharmacokinetic behaviors of AC. So these results showed that the herb-drug interaction between DST and AC might occur when they were co-administered. Therefore, the clinical dose of AC should be adjusted when DST and AC are co-administered.     

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.     

Cost-effectiveness of insulin detemir compared to NPH insulin for type 1 and type 2 diabetes mellitus in the Canadian payer setting: modeling analysis*

ABSTRACT

Objective: This study was conducted to quantify the long-term cost-effectiveness of insulin detemir (Levemir^?) versus intermediate-acting neutral protamine Hagedorn (NPH) insulin for the treatment of type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM) in Canada, and to assess the sensitivity of results to dis-utilities for hypoglycemic events.

Research design and methods: The web-based IMS-CORE diabetes model has a menu-driven interface programmed in hypertext markup language (HTML). It was used to project lifetime (60 years for T1DM and 35 years for T2DM) clinical and economic outcomes for patients on detemir vs. NPH. Cohort characteristics, utilities, and costs were derived from published literature. For T1DM, clinical trial data for HbA_1c improvement (detemir ?0.94%?±?1.07; NPH ?0.82%?±?1.01) from baseline, and rates of hypoglycemic events (major events: 0.20 vs. 0.80 per patient-year for detemir vs. NPH, respectively) were modeled. For T2DM, observational study data for HbA_1c improvement (detemir ?0.18%) from baseline, and reductions in hypoglycemic events (major events: 0.0995 vs. 1.33 per patient-year for detemir vs. NPH, respectively) were modeled. Base-case hypoglycemia dis-utilities were ?0.0118 for major and ?0.0035 for minor events. Sensitivity analyses were conducted on discount rate and hypoglycemia dis-utility.

Outcome measures: Outcomes included costs of treatment/management and costs (and incidence) of diabetes-related complications. Incremental cost-effectiveness ratios (ICERs) were calculated from differences in total costs and quality-adjusted life-years (QALYs).

Results: Average total costs for T1DM were $CAN 83?622?±?4585 for detemir and $CAN 72?016?±?4593 for NPH. QALYs increased by 0.475 years with detemir, with an ICER of $CAN 24?389/QALY. Average direct costs for T2DM were $CAN 74?919?±?6391 (detemir) and $CAN 69?230?±?6840 (NPH). QALYs increased by 0.305 years. The ICER was $CAN 18?677. Although detemir was associated with slightly lower costs for most complications, results were driven by the differences in rates and costs for hypoglycemic events, and their assumed dis-utility. Study limitations include the use of single trials for clinical assumptions and the lack of analyses for patient risk sub-groups.

Conclusions: Findings provide evidence for the cost-effectiveness of detemir vs. NPH in treating T1 and T2DM in Canada, and support the key role of assumptions regarding the impact of hypoglycemic events. Additional work is needed to determine the extent to which results are robust for different sub-groups of patients and for variation in assumptions around HbA_1c improvements and hypoglycemic event rates.     

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.     

Once-daily insulin detemir in a cohort of insulin-naïve patients with type 2 diabetes: a sub-analysis from the PREDICTIVE study

ABSTRACT

Objective: PREDICTIVE^* is a large, observational study of the empirical use of insulin detemir in patients with type 1 or type 2 diabetes (T1DM/T2DM). This post hoc analysis evaluates insulin-naïve patients with T2DM uncontrolled on oral antidiabetic drugs (OADs) who were initiated and remained on once-daily insulin detemir for 12 weeks.

Research design and methods: This observational, multinational, multi-center, open-label prospective study evaluated the efficacy and safety of insulin detemir in 1653 insulin-naïve patients with T2DM (mean age 60.8?±?10.9 years, BMI 29.8?±?4.8?kg/m², and HbA_1C 8.82?±?1.50%). Statistical comparisons were made between baseline and 12-week follow up data. Our study was subject to the usual limitations of observational studies.

Main outcome measures: Endpoints were: incidence of serious adverse drug reactions, including number of hypoglycemic events (total, major, and nocturnal), glycemic parameters, and weight change.

Results: Following insulin initiation, no significant change occurred in the number of nocturnal hypoglycemic events or total hypoglycemic events (p?=?0.4513), and no serious adverse drug reactions were observed during the 12 weeks of treatment. HbA_1C decreased by a mean 1.25% (SD?±?1.25%; p?<?0.0001), with 30% of patients (n?=?383) achieving HbA_1C <7% at 12 weeks. Mean changes in fasting blood glucose and fasting blood glucose variability were –3.62?mmol/L (SD?±?2.93; p?<?0.0001) and ?0.48?mmol/L (SD?±?1.03; p?<?0.0001), respectively. Body weight decreased by a mean 0.5?kg (SD?±?3.3; p?<?0.0001), with weight loss or no weight change occurring in a substantial percentage of patients in each BMI category (<25, 25–30, 30–35, and >35?kg/m²). Patients with higher baseline BMI lost the most weight, with the greatest weight loss (–1.20?kg) reported in those with BMI >35?kg/m².

Conclusions: Empirical use of insulin detemir as an insulin initiation strategy can improve glycemic control with good tolerability, including a low risk of hypoglycemia and a weight benefit, in a majority of insulin-naïve patients uncontrolled on OADs.     

Crataegus Aronia protects and reverses vascular inflammation in a high fat diet rat model by an antioxidant mechanism and modulating serum levels of oxidized low-density lipoprotein

Context: Crataegus aronia (Willd.) Bosc (Rosaceae) (syn. Azarolus L) is traditionally used to treat cardiovascular disorders.

Objectives: To investigate C. aronia protection against a high-fat diet (HFD)-induced vascular inflammation in rats.

Materials and methods: Wistar Male rats (180–220?g) were divided (n?=?10/group) as control fed a standard diet (STD), STD + C. aronia (200?mg/kg, orally), HFD, HFD + C. aronia and HFD post-treated with C. aronia. Simvastatin (20?mg/kg) was co- or post-administered as a positive control drug. HFD was given for 8?weeks, and all other treatments were administered for 4?weeks.

Results: Most significantly, co-administration of C. aronia to HFD-fed rats reduced the thickness of aorta tunica media (90?±?5 vs. 160?±?11.3?µm) and adventitia (54.3?±?3.8 vs. 93.6?±?9.4?µm). It also lowered protein levels of TNF-α (0.51?±?0.15 and 0.15?±?0.16 vs. 0.1?±?0.09%) and IL-6 (0.52?±?0.19 vs. 1.0?±?0.2%) in their aorta or serum (5.9?±?0.91 vs. 12.98?±?1.3?ng/mL and 78.1?±?6.7 vs. 439?±?78?pg/mL, respectively). It also lowered all serum lipids and increased aorta levels of GSH levels (70.4?±?4.0 vs. 40.7?µM) and activity of SOD (5.7?±?0.7 vs. 2.9?±?0.6?U/mg) and decreased serum levels of ox-LDL-c (566.7?±?46 vs. 1817?±?147?ng/mL). Such effects were more profound than all other treatments.

Conclusions: C. aronia inhibits the HFD-induced vascular inflammation and its use in clinical trials is recommended.     

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.     

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.     

Exenatide effects on diabetes,obesity, cardiovascular risk factors and hepatic biomarkers in patients with type 2 diabetes treated for at least 3 years

ABSTRACT

Background: Exenatide, an incretin mimetic for adjunctive treatment of type 2 diabetes (T2DM), reduced hemoglobin A_1c (A1C) and weight in clinical trials. The objective of this study was to evaluate the effects of?≥?3 years exenatide therapy on glycemic control, body weight, cardiometabolic markers, and safety.

Methods: Patients from three placebo-controlled trials and their open-label extensions were enrolled into one open-ended, open-label clinical trial. Patients were randomized to twice daily (BID) placebo, 5?µg exenatide, or 10?µg exenatide for 30 weeks, followed by 5?µg exenatide BID for 4 weeks, then 10?µg exenatide BID for ≥3 years of exenatide exposure. Patients continued metformin and/or sulfonylureas.

Results: 217 patients (64% male, age 58?±?10 years, weight 99?±?18?kg, BMI 34?±?5?kg/m², A1C 8.2?±?1.0% [mean?±?SD]) completed 3 years of exenatide exposure. Reductions in A1C from baseline to week 12 (?1.1?±?0.1% [mean?±?SEM]) were sustained to 3 years (?1.0?±?0.1%; p?<?0.0001), with 46% achieving A1C?≤?7%. Exenatide progressively reduced body weight from baseline (?5.3?±?0.4?kg at 3 years; p?<?0.0001). Patients with elevated serum alanine aminotransferase (ALT) at baseline (n?=?116) had reduced ALT (?10.4?±?1.5?IU/L; p?<?0.0001) and 41% achieved normal ALT. Patients with elevated ALT at baseline tended to lose more weight than patients with normal ALT at baseline (?6.1?±?0.6?kg vs. ?4.4?±?0.5?kg; p?=?0.03), however weight change was minimally correlated with baseline ALT (r?=??0.01) or ALT change (r?=?0.31). Homeostasis Model Assessment B (HOMA-B), blood pressure, and aspartate aminotransferase (AST) all improved. A subset achieved 3.5 years of exenatide exposure and had serum lipids available for analysis (n?=?151). Triglycerides decreased 12% (p?=?0.0003), total cholesterol decreased 5% (p?=?0.0007), LDL-C decreased 6% (p?<?0.0001), and HDL-C increased 24% (p <?0.0001). Exenatide was generally well tolerated. The most frequent adverse event was mild-to-moderate nausea. The main limitation of this study is the open-label, uncontrolled nature of the study design which does not provide a placebo group for comparison.

Conclusion: Adjunctive exenatide treatment for ≥3 years in T2DM patients resulted in sustained improvements in glycemic control, cardiovascular risk factors, and hepatic biomarkers, coupled with progressive weight reduction.     

Absorption properties and effects of caffeic acid phenethyl ester and its p-nitro-derivative on P-glycoprotein in Caco-2 cells and rats

Context: Caffeic acid phenethyl ester (CAPE), isolated from honeybee propolis, has pharmacological applications. A synthesized CAPE derivative, p-nitro-caffeic acid phenethyl ester (CAPE-NO₂), showed similar activities with CAPE. The pharmacological activities of CAPE and CAPE-NO₂ are related to their absorption properties.

Objective: To understand the pharmacokinetic profiles of CAPE and CAPE-NO₂ in rats and investigate the absorption mechanisms and effects on P-glycoprotein in Caco-2 cells.

Materials and methods: The pharmacokinetic profiles of CAPE and CAPE-NO₂ were obtained after oral administration (10?mg/kg) to rats. Transport studies of CAPE and CAPE-NO₂ (5, 10, 20?μM) were performed in Caco-2 cell model. P-gp activities were assayed by rhodamine 123 cellular retention. Expression of P-gp was determined after the cells were administrated with CAPE and CAPE-NO₂ (5, 20?μM) for 48 and 72?h.

Results: The AUC_(0?t) of CAPE-NO₂ (3239.9?±?352?ng?×?h/mL) was two-time greater than CAPE (1659.6?±?152?ng?×?h/mL) in rats. The P_app values of CAPE and CAPE-NO₂ were (4.86?±?0.90)?×?10^?6?cm/s and (12.34?±?1.6)?×?10^?6?cm/s, respectively. The accumulation of rhodamine 123 was increased by 1.3- to 1.9-fold and 1.4- to 2.3-fold in CAPE and CAPE-NO₂ groups after 1?h administration, respectively. However, CAPE and CAPE-NO₂ increased the P-gp levels by 2.1- and 1.7-fold, respectively.

Conclusion: The absorption of CAPE-NO₂ can be enhanced in rats and Caco-2 cells compared with CAPE. The two compounds are potential inhibitors of P-gp. The increased P-gp levels generated by CAPE and CAPE-NO₂ played a role as a defense mechanism by limiting intracellular xenobiotic levels.     

Studies on the antidiabetic activities of Momordica charantia fruit juice in streptozotocin-induced diabetic rats

Context: Momordica charantia Linn (Cucurbitaceae) (MC) is used in folk medicine to treat various diseases including diabetes mellitus.

Objective: This study investigates the antidiabetic activities of Momordica charantia (bitter gourd) on streptozotocin-induced type 2 diabetes mellitus in rats.

Materials and methods: Male Wister rats were randomly assigned to 4 groups. Group I, Normal control; Group II, STZ diabetic; Group III and IV, Momordica charantia fruit juice was orally administered to diabetic rats (10?mL/kg/day either as prophylaxis for 14 days before induction of diabetes then 21 days treatment, or as treatment given for 21 days after induction of diabetes). The effects of MC juice were studied both in vivo and in vitro by studying the glucose uptake of isolated rat diaphragm muscles in the presence and absence of insulin. Histopathological examination of pancreas was also performed.

Results: This study showed that MC caused a significant reduction of serum glucose (135.99?±?6.27 and 149.79?±?1.90 vs. 253.40*?±?8.18) for prophylaxis and treatment respectively, fructosamine (0.99?±?0.01 and 1.01?±?0.04 vs. 3.04?±?0.07), total cholesterol, triglycerides levels, insulin resistance index (1.13?±?0.08 and 1.19?±?0.05 vs. 1.48?±?1.47) and pancreatic malondialdehyde content (p?p?p?Conclusions: Momordica charantia presents excellent antidiabetic and antioxidant activities and thus has great potential as a new source for diabetes treatment whether it is used for prophylaxis or treatment.     

Antihyperglycemic,antilipid peroxidation,and insulin secretory activities of Otostegia persica shoot extract in streptozotocin-induced diabetic rats and in vitro C187 pancreatic β-cells

Context: Otostegia persica Boiss (Lamiaceae) contains antioxidant agents and is used in traditional medicine for treatment of diabetes mellitus complications.

Objectives: The acute antihyperglycemic, antilipid peroxidation, and insulin secretory activities of methanol extract of O. persica aerial parts were investigated.

Materials and methods: The extract [200, 300, 400?mg/kg body weight (b.w.)] was given orally to rats and glucose (2?g/kg b.w. orally) was administered 30?min later. Glucose and insulin serum levels were measured before and 30, 60, 120, and 240?min after administration of the test samples in normal and diabetic rats. The in vitro insulin secretory activity of extract was evaluated in C187 pancreatic β-cells and its antilipid peroxidation effect was determined by measuring malondialdehyde (MDA) and glutathione (GSH) levels in rat livers after 240?min. The identification of the major phytoconstituents of the extract was carried out using gas chromatography-mass spectrometry.

Results: The extract (300?mg/kg b.w.) significantly decreased the serum glucose level in diabetic rats at 1 h (494?±?13.4 vs. 426?±?12.9), 2 h (472.8?±?17.8 vs. 396?±?22), and 4?h (438.8?±?25 vs. 346?±?19) after treatment. Accordingly, the serum insulin level increased at the same times. The extract significantly increased glucose-induced insulin secretion in C187 β-cells. Moreover, the extract significantly decreased MDA and increased GSH levels in the liver of diabetic rats. Phytochemical analysis revealed thymol as the major phytoconstituent in the extract.

Discussion and conclusion: O. persica shoot extract has antihyperglycemic, antilipid peroxidation, and insulin secretory properties.     

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.     

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.