Chromogranin A-derived peptides pancreastatin and catestatin: emerging therapeutic target for diabetes.

Chromogranin A (ChgA) is an acidic pro-protein found in neuroendocrine organs, pheochromocytoma chromaffin granules, and tumor cells. Proteolytic processing of ChgA gives rise to an array of biologically active peptides such as pancreastatin (PST), vasostatin, WE14, catestatin (CST), and serpinin, which have diverse roles in regulating cardiovascular functions and metabolism, as well as inflammation. Intricate tissue-specific role of ChgA-derived peptide activity in preclinical rodent models of metabolic syndrome reveals complex effects on carbohydrate and lipid metabolism. Indeed, ChgA-derived peptides, PST and CST, play a pivotal role in metabolic syndrome such as obesity, insulin resistance, and diabetes mellitus. Additionally, supplementation of specific peptide in ChgA-KO mice have an opposing effect on physiological functions, such as PST supplementation reduces insulin sensitivity and enhances inflammatory response. In contrast, CST supplementation enhances insulin sensitivity and reduces inflammatory response. In this review, we focus on the tissue-specific role of PST and CST as therapeutic targets in regulating carbohydrate and lipid metabolism, along with the associated risk factors.

Pancreastatin inhibitor PSTi8 ameliorates insulin resistance by decreasing fat accumulation and oxidative stress in high-fat diet-fed mice.

Abnormal fat accumulation, enhanced free fatty acids (FFA) release, and their metabolites cause insulin resistance (IR) in major glucose-lipid metabolic organs such as skeletal muscle and adipose tissue. However, excessive lipolysis and FFA release from adipose tissue elevate plasma FFA levels leading to oxidative stress and skeletal muscle IR. Indeed, in obese individuals, there is enhanced pro-inflammatory secretion from adipose tissue influencing insulin signaling in skeletal muscles. Here, we investigated the effect of PSTi8 on FFA-induced IR in both in vitro and in vivo models. Palmitate (Pal)-treated 3T3-L1 cells increased lipid accumulation as well as lipolysis, which reduced the insulin-stimulated glucose uptake. PSTi8 treatment significantly prevented Pal-induced lipid accumulation, and release and enhanced insulin-stimulated glucose uptake. It further reduced the release of pro-inflammatory cytokines from Pal-treated 3T3-L1 cells as well as from adipose tissue explants. In addition, PSTi8 treatment decreases M1 surface markers in Pal-treated bone marrow-derived monocytes (BMDM). PSTi8 treatment also significantly enhanced the Pal-mediated reduced skeletal muscle glucose disposal and reduced intracellular oxidative stress. In vitro effect of PSTi8 was consistent with in vivo HFD-fed mice IR model. PSTi8 treatment in HFD-fed mice significantly improved glucose metabolism and enhanced skeletal muscle insulin sensitivity with reduced adiposity and pro-inflammatory cytokines. Taken together, our results support that PSTi8 treatment can protect both adipose and skeletal muscles from FFA-induced IR.

The combined effect of Raspberry Ketone with Resveratrol against oxidative stress and steatohepatitis in rats: Pharmacokinetic and pharmacodynamic studies.

Raspberry Ketone (RK) and Resveratrol (RSV) are natural phenolic antioxidants and anti-inflammatory agents. However, its combined pharmacokinetic and pharmacodynamics potentials are not reported. The study aims to assess the combined effect of RK with RSV to protect rats from carbon-tetrachloride (CCl4) induced oxidative stress and NASH. The toxicant CCl4 was employed at a concentration of 1 mL/kg as a 1:1 (v/v) mixture with olive oil twice weekly for 6 weeks to induce liver toxicity. Animal treatment was followed for 2 weeks. Silymarin was used as a standard control drug to compare the hepatoprotective effect of RK and RSV. Hepatic histology, oxidative stress, MMP, reduced glutathione (GSH), plasma levels of SGOT, SGPT, and lipid profile (total cholesterol and triglycerides) were measured. Anti-inflammation genes (IL-10), and fibrotic genes (TGF-ß) were also examined in liver tissue. Oral administration of combined RK with RSV (50 + 50 mg/kg for 2 weeks) showed significantly more hepatoprotection by significantly decreasing elevated plasma markers and lipid profile than alone RK and RSV (100 mg/kg daily for 2 weeks). It also significantly alleviated the hepatic lipid peroxidation, restoring the activities of GSH levels in the liver. RT-PCR and Immunoblotting studies confirmed that significantly upregulation of anti-inflammation genes and protein expression (MMP-9) ameliorated the disease. Pharmacokinetic studies confirmed more synergistic stability in simulated gastric-intestinal fluids (FaSSGF, FaSSIF) and rat liver microsomes (CYP-450, NADPH oxidation & glucuronidation. Moreover, coadministration of drugs augmented the relative bioavailability, Vd/ F (L/Kg), and MRT0-∞( h), which leads to more efficacy. This pharmacokinetic and pharmacodynamic reveals a new adjuvant therapy for the treatment of steatohepatitis.

Augmented experimental design for bioavailability enhancement: a robust formulation of abiraterone acetate.

Abiraterone acetate (ABRTA) is clinically beneficial in management of metastatic castration-resistant prostate cancer (PC-3). With highlighted low solubility and permeability, orally hampered treatment of ABRTA necessitate high dose to achieve therapeutic efficacy. To triumph these challenges, we aimed to develop intestinal lymphatic transport facilitating lipid-based delivery to enhance bioavailability. ABRTA-containing self-nano emulsified drug delivery (ABRTA-SNEDDS) was statistically optimized by D-optimal design using design expert. Optimized formulation was characterized for particle size, thermodynamic stability, in vitro release, in vivo bioavailability, intestinal lymphatic transport, in vitro cytotoxic effect, anti-metastatic activity, and apoptosis study. Moreover, hemolysis and histopathology studies have been performed to assess pre-clinical safety. Nano-sized particles and successful saturated drug loading were obtained for optimized formulation. In vitro release upto 98.61 ± 3.20% reveal effective release of formulation at intestinal pH 6.8. ABRTA-SNEDDS formulation shows enhanced in vivo exposure of Abiraterone (2.5-fold) than ABRTA suspension in Sprague-Dawley rats. In vitro efficacy in PC-3 cell line indicates 3.69-fold higher therapeutic potential of nano drug delivery system. Hemolysis and histopathology study indicates no significant toxicities to red blood cells and tissues, respectively. Apparently, an opportunistic strategy to increasing bioavailability of ABRTA via intestinal lymphatic transport will create a viable platform in rapidly evolving chemotherapy. Enhanced translational utility of delivery was also supported through in vitro therapeutic efficacy and safety assessments. HighlightsAbiraterone acetate is a prostate cancer drug, impeded with low bioavailability.ABRTA loaded in self nano emulsifying drug delivery enhanced its bioavailability.Intestinal lymphatic transport played role in enhanced bioavailability of ABRTA.ABRTA-SNEDDS enhanced in vitro cytotoxic activity of ABRTA.ABRTA-SNEDDS found safe in preclinical safety evaluations.

Cissus quadrangularis extract mitigates diabetic cardiomyopathy by inhibiting RAAS activation, inflammation and oxidative stress.

BACKGROUND: Diabetic cardiomyopathy (DCM) is an age-related disease, and its progression is accompanied by hyperglycaemia, cardiac dysfunction, and myocardial structural and functional abnormalities. Cissus quadrangularis, a traditional medicinal plant, contains polyphenols, flavonoids, phytosterols, carbohydrates and ascorbic acid. It is used to treat osteoporosis, asthma, haemorrhoids and menstrual disorders.Objective: In the current research, we have investigated the effect of ethanolic extract of C. quadrangularis (EECQ) against a high-fat diet (HFD)/streptozotocin-induced DCM by estimating cardiac biomarkers, inflammatory markers and Reactive oxygen species (ROS) production. MATERIAL AND METHODS: Rats were fed with an HFD for 12 weeks, followed by single-shot low-dose streptozotocin (35 mg/kg; i.p.). The treatment was performed by EECQ (200 mg/kg/day, orally) for six weeks. RESULTS: The extract EECQ improves glucose, insulin tolerance tests and hypercholesteremia. DCM is characterized by cardiac dysfunction, cardiac biomarkers CKMB and LDH, which were attenuated by the EECQ treatment. The hypertrophic biomarker ANP, BNP expression and cardiomyocyte surface area were decreased by EECQ. Moreover, EECQ also alleviated the biomarkers Angiotensin II and renin level. EECQ also reduced oxidative stress, ROS production and cardiac inflammation. CONCLUSIONS: Thus, these findings suggested that EECQ could be used as a possible therapeutic regiment to treat DCM.

Cissus quadrangularis ameliorates hyperglycaemia, hyperinsulinemia and hyperlipidaemia.Cissus quadrangularis mitigates cardiac dysfunction.Cissus quadrangularis decreases RAAS activation, thereby down-regulates ANP, BNP expression.Cissus quadrangularis alleviates ROS propagated oxidative stress and apoptosis.

Evaluation of the Pharmacokinetics of the Pancreastatin Inhibitor PSTi8 Peptide in Rats: Integration of In Vitro and In Vivo Findings.

PSTi8 is a pancreastatin inhibitory peptide that is effective in the treatment of diabetic models. This study investigates the pharmacokinetic (PK) properties of PSTi8 in Sprague Dawley rats, for the first time. In vitro and in vivo PK studies were performed to evaluate the solubility, stability in plasma and liver microsomes, plasma protein binding, blood-plasma partitioning, bioavailability, dose proportionality, and gender difference in PK. Samples were analyzed using the validated LC-MS/MS method. The solubility of PSTi8 was found to be 9.30 and 25.75 mg/mL in simulated gastric and intestinal fluids, respectively. The protein binding of PSTi8 was estimated as >69% in rat plasma. PSTi8 showed high stability in rat plasma and liver microsomes and the blood-plasma partitioning was >2. The bioavailability of PSTi8 after intraperitoneal and subcutaneous administration was found to be 95.00 ± 12.15 and 78.47 ± 17.72%, respectively, in rats. PSTi8 showed non-linear PK in dose proportionality studies, and has no gender difference in the PK behavior in rats. The high bioavailability of PSTi8 can be due to high water solubility and plasma protein binding, low clearance and volume of distribution. Our in vitro and in vivo findings support the development of PSTi8 as an antidiabetic agent.

Emerging nanotechnology based combination therapies of taxanes for multiple drug-resistant cancers.

'One drug- one target' to 'multiple drug- multiple targets' paradigm shifted to produce combination therapies, have found great outcomes to overcome multiple drug resistance (MDR). MDR is a significant barrier to the delivery of taxane-based anticancer medicines such as docetaxel, paclitaxel, and cabazitaxel. Due to MDR induced by drug efflux transporters, clinical application of these medications is impeded. To date, nanoformulations such as liposomes, micelles, polymeric nanoparticles, and gold nanoparticles have been investigated to deliver taxanes alone and in combination to reverse drug resistance. Despite the fact that various groups have already looked into taxane nano formulations in the literature, there isn't much in the way of polypharmacology and advanced nanoformulations with a focus on MDR. In this overview, we briefly covered the insights regarding MDR, difficulties related to current pharmaceutical products of taxanes, combination therapies of taxanes to combat MDR, all of which can be used to delve into cancer treatment.

Challenges of peptide and protein drug delivery by oral route: Current strategies to improve the bioavailability.

Advancement in biotechnology provided a notable expansion of peptide and protein therapeutics, used as antigens, vaccines, hormones. It has a prodigious potential to treat a broad spectrum of diseases such as cancer, metabolic disorders, bone disorders, and so forth. Protein and peptide therapeutics are administered parenterally due to their poor bioavailability and stability, restricting their use. Hence, research focuses on the oral delivery of peptides and proteins for the ease of self-administration. In the present review, we first address the main obstacles in the oral delivery system in addition to approaches used to enhance the stability and bioavailability of peptide/protein. We describe the physiochemical parameters of the peptides and proteins influencing bioavailability in the systemic circulation. It encounters, many barriers affecting its stability, such as poor cellular membrane permeability at the GIT site, enzymatic degradation (various proteases), and first-pass hepatic metabolism. Then describe the current approaches to overcome the challenges mentioned above by the use of absorption enhancers or carriers, structural modification, formulation and advance technology.

Pharmacokinetics and brain targeting of trans-resveratrol loaded mixed micelles in rats following intravenous administration.

Trans-Resveratrol (T-RES) is a compound with wide therapeutic applications that shows low bioavailability and distribution across blood-brain barrier. The purpose of our study was to develop T-RES loaded mixed micelle (T-RES-MM) for its enhanced systemic availability and targeting to the brain. T-RES-MMs were formulated using Pluronic F-127 (PF-127) and d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) by using film hydration process. Formulations were characterized for size of particles, zeta potential, drug efficiency of entrapment, drug loading, and hemolytic study. Further in vivo pharmacokinetic and brain distribution study carried out in Sprague Dawley rats. The nano ranged size for drug-loaded mixed micelles was 21.55 ± 2.15 nm for optimized formulation with PF-127:TPGS (4:1). Formulation with maximum drug loading and entrapment efficiency of 8.4 ± 0.37% and 94.37 ± 1.01% respectively were further used for in vivo study. Percent hemolysis by micelles at all concentrations indicates the biocompatibility and safety for administration by i.v. route. The AUC0-t for T-RES-MM was 460.98 ± 158.99 h*ng/ml while for T-RES it was 276.27 ± 174.05 h*ng/ml. Drug targeting index suggests successful targeting of T-RES to the brain. Overall findings conclude in prepared T-RES-MM exhibit superiority of formulation as compared to T-RES solution.

Pancreastatin inhibitor PSTi8 ameliorates streptozotocin-induced diabetes by suppressing hepatic glucose production.

Elevated plasma glucose concentration, as a consequence of excessive hepatic glucose production, plays a pivotal role in the development of diabetes. A chromogranin A-derived diabetogenic peptide Pancreastatin (PST) enhances hepatic glucose output leading to diabetes. Therefore, here we probed the role of PSTi8, a PST inhibitor in ameliorating diabetes by investigating the effect of high glucose (HG) or PST on glucose metabolism. Further, we also explored the action mechanism of the underlying anti-hyperglycemic effect of PSTi8. PSTi8 treatment rescue cultured L6 and HepG2 cells from HG and PST-induced insulin resistance, respectively. It also enhances insulin receptor kinase activity by interacting with the insulin receptor and enhancing GLUT4 translocation and glucose uptake. Thus, our in-silico and in-vitro data support the PST-dependent and independent activity of PSTi8. Additionally, PSTi8 treatment in streptozotocin-induced diabetic rats improved glucose tolerance by lowering blood glucose and plasma PST levels. Concomitantly, the treated animals exhibited reduced hepatic glucose production accompanied by downregulation of hepatic gluconeogenic genes PEPCK and G6Pase. PSTi8-treated rats also exhibited enhanced hepatic glycogen in line with reduced plasma glucagon concentrations. Consistently, improved plasma insulin levels in PSTi8-treated rats enhanced skeletal muscle glucose disposal via enhanced P-Akt expression. In summary, these findings suggest PSTi8 has anti-hyperglycemic properties with enhanced skeletal muscle glucose disposal and reduced hepatic gluconeogenesis both PST dependent as well as independent.

LC-MS/MS method for quantification of raspberry ketone in rat plasma: application to preclinical pharmacokinetic studies.

Background: Raspberry ketone (RK), derived from red raspberry fruit (Rubus idaeus, family Rosaceae), is a reported potent antiobesity agent. This study aims to investigate method development, validation, and in vitro and in vivo pharmacokinetics in rats. Materials & methods: LC-MS/MS was used to conduct method development, validation, stability, and oral PK samples of RK in plasma analyses. Results: RK was highly soluble in Tris buffer and stable in gastrointestinal fluids as well as plasma. Rat liver microsomal stability of RK in phase I and II studies was 84.96 ± 2.39 and 69.98 ± 8.69%, respectively, after 60 min. Intestinal permeability was 4.39 ± 1.37 × 10-5 cm/s. Maximal concentration was 1591.02 ± 64.76 ng/ml, which was achieved after 1 h (time to maximal concentration), and absolute oral bioavailability was 86.28%. Conclusion: Pharmacokinetic data serve as a keystone for preclinical and clinical adjuvant therapy.

Using LC­MS/MS, a method was developed and validated for RK, and investigated the preclinical pharmacokinetics and bioavailability in Sprague Dawley rats.

Pancreastatin inhibitor PSTi8 prevents free fatty acid-induced oxidative stress and insulin resistance by modulating JNK pathway: In vitro and in vivo findings.

AIM: Free fatty acid-mediated obesity plays a crucial role in the pathogenesis of Type 2 Diabetes. FFA induced JNK activation acts as a central regulator in causing hepatic insulin resistance. Similarly, Pancreastatin, a chromogranin A peptide, serves as a crucial link between FFA-induced insulin resistance. Therefore, in the present work, we sought to test Pancreastatin inhibitor PSTi8 to ameliorate FFA-induced hepatic insulin resistance in in vitro and in vivo models. MATERIAL AND METHODS: To verify our objective, we exposed hepatocytes (HepG2 cells) with palmitate (0.3 mM) or palmitate + PSTi8 (200 nM). Parallelly mice were fed either HFD or HFD + PSTi8 (1 mg/kg). After 21 days animals were scanned for increased fat mass, along with GTT, ITT and PTT experiment to check glucose, and insulin tolerance. Furthermore, ROS generation and hepatic glycogen content was measured in FFA exposed hepatocytes. Gene expression and protein expression studies were further conducted to delineate the action mechanism of PSTi8. KEY FINDINGS: PSTi8 exposure decreased ROS accumulation, lipid accumulation, and reduced glycogen content in FFA-induced groups. It also enhances glucose uptake and reduces gluconeogenesis to combat the FFA effect. Furthermore, gene expression studies indicate that PSTi8 treatment reduces NADPH oxidase3 (NOX3) expression and inhibits JNK signaling, a predominant source of ROS-induced insulin resistance. SIGNIFICANCE: To summarize, the protective effect of PSTi8 on FFA-induced insulin resistance is mediated via inhibition of JNK signaling, which leads to decreased ROS generation and enhanced insulin sensitivity. Hence PSTi8 could be a therapeutic molecule to prevent western diet-induced insulin resistance.

Diosmin, a citrus fruit-derived phlebotonic bioflavonoid protects rats from chronic kidney disease-induced loss of bone mass and strength without deteriorating the renal function.

Kidney Disease Improving Global Outcomes (KDIGO) 2017 Clinical Practice Guideline has recommended treatment decisions for patients with chronic kidney disease (CKD) with osteoporosis and/or high risk of fracture. Bisphosphonates, the first-line anti-osteoporosis drugs have the concern of worsening kidney functions. Moreover, despite impaired bone formation in CKD patients, teriparatide, the formation-stimulating drug is not recommended. Thus, there is an urgent need for safe and effective treatment of osteoporosis in CKD patients. Here, in CKD rats, we tested the osteoprotective effect of diosmin, a citrus-derived bioflavonoid used as a phlebotonic in chronic venous insufficiency and has a renoprotective effect. CKD was developed by 5/6th nephrectomy and diosmin at the human equivalent dose (100 mg kg-1) did not advance renal failure but reduced blood pressure to the level of sham control. Fibroblast growth factor-23 and parathyroid hormone were increased in CKD and diosmin suppressed both. CKD reduced bone mass and deteriorated the microarchitecture of trabecular bones, and diosmin maintained both to control levels. Bone formation and strength were impaired in the CKD and diosmin maintained these levels to control levels. Nanoindentation of bone showed that diosmin significantly increased tissue hardness over the control. Diosmetin, the metabolic surrogate of diosmin had comparable pharmacokinetic profiles between the control and CKD groups. Furthermore, diosmetin (50 mg kg-1) protected against CKD-induced bone loss. These data suggest that diosmin and its metabolic surrogate, diosmetin protect against CKD-induced osteopenia. Since diosmin has no renal adverse effect and protected bone mass and strength in CKD rats, we propose assessing its anti-osteoporosis effect in CKD patients.

Pancreastatin mediated regulation of UCP-1 and energy expenditure in high fructose fed perimenopausal rats.

AIMS: Pancreastatin (PST) is a crucial bioactive peptide derived from chromogranin A (CHGA) proprotein that exhibits an anti-insulin effect on adipocytes. Herein, we investigated the effects of PST on brown adipose tissues (BAT) and white adipose tissue (WAT) in connection with uncoupling protein-1 (UCP-1) regulated energy expenditure in high fructose diet (HFrD) fed and vinylcyclohexenediepoxide (VCD) induced perimenopausal rats. MATERIAL AND METHODS: We administered VCD in rats for 17 consecutive days and fed HFrd for 12 weeks. After 12 weeks estradiol and progesterone levels were detected. Furthermore, detection of glucose tolerance, insulin sensitivity, and body composition revealed impaired glucose homeostasis and enhanced PST levels. Effects of enhanced PST on UCP-1 level in BAT and WAT of perimenopausal rats were further investigated. KEY FINDINGS: Reduced serum estradiol, progesterone, and attenuated insulin response confirmed perimenopausal model development. Furthermore, enhanced PST serum level and its increased expression in BAT and WAT downregulated the UCP-1 expression. Subsequently, impaired ATP level, NADP/NADPH ratio, citrate synthase activity, enhanced mitochondrial reactive oxygen species (ROS) generation and perturbed mitochondrial membrane potential, further exacerbated mitochondrial dysfunction, cellular ROS production, and promoted apoptosis. Interestingly, PST inhibition by PST inhibitor peptide-8 (PSTi8) displayed a favorable impact on UCP-1 and energy expenditure. SIGNIFICANCE: The aforementioned outcomes indicated the substantial role of PST in altering the UCP-1 expression and associated energy homeostasis. Hence our results corroborate novel avenues to unravel the quest deciphering PST's role in energy homeostasis and its association with perimenopause.

JNK signaling pathway in metabolic disorders: An emerging therapeutic target.

Metabolic Syndrome is a multifactorial disease associated with increased risk of cardiovascular disorders, type 2 diabetes mellitus, fatty liver disease, etc. Various stress stimuli such as reactive oxygen species, endoplasmic reticulum stress, mitochondrial dysfunction, increased cytokines, or free fatty acids are known to aggravate progressive development of hyperglycemia and hyperlipidemia. Although the exact mechanism contributing to altered metabolism is unclear. Evidence suggests stress kinase role to be a crucial one in metabolic syndrome. Stress kinase, c-jun N-terminal kinase activation (JNK) is involved in various metabolic manifestations including obesity, insulin resistance, fatty liver disease as well as cardiometabolic disorders. It emerged as a foremost mediator in regulating metabolism in the liver, skeletal muscle, adipose tissue as well as pancreatic ß cells. It has three isoforms each having a unique and tissue-specific role in altered metabolism. Current findings based on genetic manipulation or chemical inhibition studies identified JNK isoforms to play a central role in the regulation of whole-body metabolism, suggesting it to be a novel therapeutic target. Hence, it is imperative to elucidate its role in metabolic syndrome onset and progression. The purpose of this review is to elucidate in vitro and in vivo implications of JNK signaling along with the therapeutic strategy to inhibit specific isoform. Since metabolic syndrome is an array of diseases and complex pathway, carefully examining each tissue will be important for specific treatment strategies.

Correction: Simultaneous quantification of five biomarkers in ethanolic extract of Cassia occidentalis Linn. stem using liquid chromatography tandem mass spectrometry: application to its pharmacokinetic studies.

[This corrects the article DOI: 10.1039/C9RA07482A.].

PSTi8 with metformin ameliorates perimenopause induced steatohepatitis associated ER stress by regulating SIRT-1/SREBP-1c axis.

AIMS: Hepatic steatosis in women confronting menopause is the manifestation of substantial fructose consumption and forms a positive feedback loop to develop endoplasmic reticulum (ER) stress. Previously pancreastatin inhibitor peptide-8 (PSTi8) and Metformin (Met) combination effectively ameliorated hepatic lipid accumulation in high fructose diet (HFrD) fed diabetic mice models at reduced doses. Moreover, SIRT-1 plays a crucial role in the regulation of SREBP-1c. Hence we hypothesized that Met and PSTi8 in combination (at therapeutic lower doses) could mitigate hepatic steatosis linked ER stress by activating SIRT-1 and precluding SREBP-1c in HFrD fed 4-Vinylcyclohexenediepoxide (HVCD) induced perimenopausal rats. MAIN METHODS: HVCD rats were fed HFrD for 12 weeks, accompanied by 14 days of treatment with Met, PSTi8, and combination. We confirmed model establishment by estrus cycle study, estradiol level, and intraperitoneal glucose tolerance test. Plasma lipid profile and liver function were determined. Also, mRNA and protein expressions were examined. Moreover, distribution of SIRT-1 and SREBP-1c was detected in HepG2 cells by immunofluorescence staining. KEY FINDINGS: HVCD group displayed augmented insulin resistance (IR), lipogenesis, and ER stress in the liver. Combination therapy improved the estrus cyclicity, estradiol, and lipid profile of HVCD rats. Met and PSTi8 combination reduced hepatic SREBP-1c and triggered SIRT-1 expression in high fructose-induced insulin-resistant HepG2 cells; consequently, combination therapy attenuated ER stress. SIGNIFICANCE: Succinctly, present research promotes impetus concerning the remedial impact of Met with PSTi8 at lower therapeutic doses to ameliorate hepatic IR, steatosis, and associated ER stress by revamping the SIRT-1/SREBP-1c axis in perimenopausal rats.

Simultaneous quantification of five biomarkers in ethanolic extract of Cassia occidentalis Linn. stem using liquid chromatography tandem mass spectrometry: application to its pharmacokinetic studies.

Cassia occidentalis L. stem extract is used as a purgative, febrifuge, and diuretic, and in the treatment of flu, fever, fracture and bone diseases. Pharmacological studies prove the osteogenic and antiresorptive effects of Cassia occidentalis L. ethanolic extract (COEE), which may be due to apigenin, apigenin-6-C-glucopyranoside, luteolin, 3',4',7-trihydroxyflavone and emodin. The objectives of this study was to develop a selective and sensitive LC-MS/MS method and validate for the simultaneous determination of the above five biomarkers in rat plasma after oral administration of COEE at a dose of 500 mg kg-1. The analytes were separated on a Phenomenex Luna C18 column (4.6 × 150 mm, 3.0 µm) with an isocratic mobile phase consisting of methanol-10 mM ammonium acetate buffer (95 : 05, v/v). Run time was for 5.5 min with LLOQ of 1 ng mL-1 for all the analytes. The mass spectrometer was operating in negative ionization mode for quantification of the analytes. The calibration curves were linear (r 2 > 0.99) for all the analytes. The intra- and inter-day precisions were less than 8.17% and the relative error was between -8.57% and 7.28%. Analytes were rapidly absorbed in the oral pharmacokinetic study. The biomarkers were stable in simulated gastric and intestinal fluids but underwent metabolism in rat liver microsomes. This is the first report on in vivo oral pharmacokinetics and in vitro stability studies of osteogenic compounds present in COEE. These results will be helpful for further understanding of pharmacodynamic behaviour of COEE and the bioanalytical method will be useful for further preclinical/clinical trials.

Elucidation of pharmacokinetics of novel DNA ligase I inhibitor, S012-1332 in rats: Integration of in vitro and in vivo findings.

S012-1332 is the first DNA ligase I inhibitor that demonstrated in vivo anti-breast cancer activity. The present study aimed to assess the in vivo pharmacokinetics of S012-1332 in rats and interpret them with in vitro findings. A sensitive and selective liquid chromatography-tandem mass spectrometry bioanalytical method was developed and validated to determine S012-1332. Following oral administration, the absolute bioavailability was 7.04%. The absorption was prolonged which can be explained by low solubility in simulated gastric fluid and several folds higher solubility in simulated intestinal fluid. The effective permeability across the intestinal membrane in in situ single pass perfusion study for S012-1332 was 5.58 ± 1.83 * 10-5 cm/sec compared to 5.99 ± 0.65 * 10-5 cm/sec for carbamazepine, with no significant difference, indicating S012-1332 has high permeability. It was rapidly partitioning into plasma in blood, where it was stable. Plasma protein binding was moderate which may have attributed to the rapid distribution out of the vascular compartment. The pharmacokinetics of S012-1332 was characterized by extensive clearance as seen with rat liver and intestinal microsomes. In vitro results elucidate the in vivo pharmacokinetic data. These findings provide crucial information for further development of S012-1332 as anti-breast cancer agent.