Oral Glucose Tolerance Test (OGTT) Evidence for the Postprandial Anti-Hyperglycemic Property of Salacca zalacca (Gaertn.) Voss Seed Extract.

Salak seed extract (Salacca zalacca) is known for its high antioxidant content and low caffeine levels, making it a promising candidate for the development of value-added health products. However, there is a lack of scientific evidence for its anti-hyperglycemic effects. To address this, we investigated the in vitro and in vivo anti-hyperglycemic and antioxidant effects of salak seed extract. The HPLC chromatogram of salak seed extract shows a prominent peak that corresponds to chlorogenic acid. In vitro studies revealed that salak seeds inhibited α-glucosidase activity and glucose uptake in Caco-2 cells in a concentration-dependent manner, while also exhibiting antioxidant properties. The extract exhibits a non-competitive inhibition on α-glucosidase activity, with an IC50 and Ki of 16.28 ± 7.22 and 24.81 µg/mL, respectively. In vivo studies utilizing streptozotocin-nicotinamide-induced diabetic mice showed that the extract significantly reduced fasting blood glucose (FBG) levels in the oral glucose tolerance test. Continuous administration of the salak seed extract resulted in lower FBG levels by 13.8% as compared with untreated diabetic mice, although this change was not statistically significant. The estimated LD50 value of salak seed extract exceeds 2000 mg/kg, and no toxicity symptoms have been detected. Our research supports that salak seed extract has the potential to serve as a functional food or supplement that may be beneficial in reducing postprandial hyperglycemia among people with type 2 diabetes. This effect was explained by the salak's inhibitory mechanisms of glucose absorption due to inhibition of both α-glucosidase activity and intestinal glucose uptake, coupled with its antioxidant effects.

Antihyperglycemic effects of Lysiphyllum strychnifolium leaf extract in vitro and in vivo.

CONTEXT: Lysiphyllum strychnifolium (Craib) A. Schmitz (LS) (Fabaceae) has traditionally been used to treat diabetes mellitus. OBJECTIVE: This study demonstrates the antidiabetic and antioxidant effects of aqueous extract of LS leaves in vivo and in vitro. MATERIALS AND METHODS: The effects of aqueous LS leaf extract on glucose uptake, sodium-dependent glucose cotransporter 1 (SGLT1) and glucose transporter 2 (GLUT2) mRNA expression in Caco-2 cells, α-glucosidase, and lipid peroxidation were evaluated in vitro. The antidiabetic effects were evaluated using an oral glucose tolerance test (OGTT) and a 28-day consecutive administration to streptozotocin (STZ)-nicotinamide (NA)-induced type 2 diabetic mice. RESULTS: The extract significantly inhibited glucose uptake (IC50: 236.2 ± 36.05 µg/mL) and downregulated SGLT1 and GLUT2 mRNA expression by approximately 90% in Caco-2 cells. Furthermore, it non-competitively inhibited α-glucosidase in a concentration-dependent manner with the IC50 and Ki of 6.52 ± 0.42 and 1.32 µg/mL, respectively. The extract at 1000 mg/kg significantly reduced fasting blood glucose levels in both the OGTT and 28-day consecutive administration models as compared with untreated STZ-NA-induced diabetic mice (p < 0.05). Significant improvements of serum insulin, homeostasis model assessment of insulin resistance (HOMA-IR), and GLUT4 levels were observed. Furthermore, the extract markedly decreased oxidative stress markers by 37-53% reduction of superoxide dismutase 1 (SOD1) in muscle and malondialdehyde (MDA) in muscle and pancreas, which correlated with the reduction of MDA production in vitro (IC50: 24.80 ± 7.24 µg/mL). CONCLUSION: The LS extract has potent antihyperglycemic activity to be used as alternative medicine to treat diabetes mellitus.

Pharmacological effects of Chatuphalatika in hyperuricemia of gout.

CONTEXT: Chatuphalatika (CTPT), is a Thai herbal formulation mixture of Phyllanthus emblica Linn. (Euphorbiaceae), Terminalia belerica Linn. (Combretaceae), T. chebula and the fruit of T. arjuna (Roxb.) Wight & Arn. CTPT is considered to exert anti-inflammatory and antihyperuricemic effects, but there have been no reports to demonstrate these pharmacological effects in a quantitative manner. OBJECTIVES: To investigate the antioxidative, anti-inflammatory and antihyperuricemic effects of CTPT. MATERIALS AND METHODS: Antioxidant activities of CTPT extracts were measured in vitro by DPPH, ABTS and FRAP assays, and anti-inflammatory effect by measuring inflammatory mediator production induced by lipopolysaccharide (LPS) in RAW264.7 macrophages. The mechanism of the hypouricemic effect was investigated using oxonate-induced hyperuricemic ddY mice treated with oral administrations of CTPT at 250, 500 and 1000 mg/kg. RESULTS: Antioxidant activities of CTPT measured by ABTS and FRAP assays were 1.35 g TEAC/g extract and 10.3 mmol/100 g extract, respectively. IC50 for the inhibition of DPPH radical was 13.8 µg/mL. CTPT (10 µg/mL) significantly downregulated the mRNA expression of TNF-α and iNOS in RAW 264.7 cells. Lineweaver-Burk analysis of the enzyme kinetics showed that CTPT inhibited xanthine oxidase (XOD) activity in a noncompetitive manner with the Ki of 576.9 µg/mL. Oral administration of CTPT (1000 mg/kg) significantly suppressed uric acid production by inhibiting hepatic XOD activity, and decreased plasma uric acid levels in hyperuricemic mice by approximately 40% (p < 0.05). CONCLUSIONS: This study demonstrated for the first time the antioxidative, anti-inflammatory and antihyperuricemic effects of CTPT in vivo and in vitro, suggesting a possibility of using CTPT for the treatment of hyperuricemia in gout.

Inhibitory effects of Triphala on CYP isoforms in vitro and its pharmacokinetic interactions with phenacetin and midazolam in rats.

Context: Direct evidence of Triphala-drug interactions has not been provided to date. Objective: This study was aimed to determine the effects of Triphala on cytochrome P450 (CYP) isoforms and P-glycoprotein (P-gp) in vitro, and to investigate pharmacokinetic interactions of Triphala with CYP-probes in rats. Materials and methods: Effects of Triphala on the activities of CYP isoforms and P-gp were examined using human liver microsomes (HLMs) and Caco-2 cells, respectively. Pharmacokinetic interactions between Triphala and CYP-probes (i.e., phenacetin and midazolam) were further examined in rats. Results: Triphala extract inhibited the activities of CYP isoforms in the order of CYP1A2>3A4>2C9>2D6 with the IC50 values of 23.6 ± 9.2, 28.1 ± 9.8, 30.41 ± 16.7 and 93.9 ± 27.5 µg/mL, respectively in HLMs. It exhibited a non-competitive inhibition of CYP1A2 and 2C9 with the K i values of 23.6 and 30.4 µg/mL, respectively, while its inhibition on CYP3A4 was competitive manner with the Ki values of 64.9 µg/mL. The inhibitory effects of Triphala on CYP1A2 and 3A4 were not time-dependent. Moreover, Triphala did not affect the P-gp activity in Caco-2 cells. Triphala, after its oral co-administration at 500 mg/kg, increased the bioavailabilities of phenacetin and midazolam by about 61.2% and 40.7%, respectively, in rats. Discussion and conclusions: Increases observed in the bioavailabilities of phenacetin and midazolam after oral co-administration of Triphala in rats provided a direct line of evidence to show Triphala-drug interactions via inhibition of CYP1A and CYP3A activities, respectively. These results, together with the lack of time-dependency of CYP 1A2 and 3A4 inhibition in vitro, suggested that the inhibitory effect of Triphala is primarily reversible.

Evaluation of in vitro transdermal permeation, mass spectrometric imaging, and in vivo analgesic effects of pregabalin using a pluronic lecithin organogel formulation in mice.

In clinical practice, pregabalin is orally administered for neuropathic pain, but causes severe central nervous system side effects, such as dizziness, which results in dose limitation or discontinuation. To reduce the central side effects of pregabalin, we developed four pregabalin preparations for transdermal application: 0.4% aqueous solution, pluronic lecithin organogel (PLO gel), hydrophilic cream, and lipophilic cream. Transdermal permeabilities of pregabalin among the four formulations were compared in vitro using hairless mouse skin. The longitudinal distribution of pregabalin within the skin was analyzed using mass spectrometric (MS) imaging. Furthermore, the in vivo analgesic effects of the formulations were evaluated using the von Frey filament test in a mouse model of diabetic neuropathy (DN). The PLO gel showed the highest permeability of pregabalin, followed by the aqueous solution, and no permeation was observed in the two cream formulations. The MS imaging analysis showed that pregabalin was distributed up to the dermis in the PLO gel 1 h after application, while the aqueous solution was distributed near the epidermis. A significant analgesic effect (p < .05) was observed 1.5 h after PLO gel application in the DN model mice, but the aqueous solution had no effect. This study indicated for the first time that pregabalin penetrated beyond the skin epidermis up to the dermis, from the PLO gel formulation, and that the application of this formulation exhibited an in vivo analgesic effect in the mouse model of DN.

Antidiabetic effects of Maclura cochinchinensis (Lour.) corner heartwood extract.

BACKGROUND AND AIM: Maclura cochinchinensis (MC) (Lour.) heartwood extract have been used traditionally to treat diabetes in Thailand, but their mechanism of action has not been elucidated. EXPERIMENTAL PROCEDURE: This study investigated the effects of an aqueous heartwood extract of MC on α-glucosidase and α-amylase activities. Moreover, its antidiabetic effect was evaluated using an oral glucose tolerance test (OGTT) and a 28-day administration to streptozotocin (STZ)-nicotinamide (NA)-induced type 2 diabetic mice. RESULTS: In both OGTT and the daily oral administration for 28 days in STZ-NA-induced type 2 diabetic mice models, the extract (1,000 mg/kg) significantly decreased fasting blood glucose. This hypoglycemic effect was explained by increased insulin levels and α-glucosidase inhibition (IC50:1.53 ±â€¯0.03 µg/mL). CONCLUSION: This first study on the hypoglycemic activity of MC heartwood extract indicates that it could be a potential natural remedy for type 2 diabetes.

The selective cytotoxicity of silver thiosulfate, a silver complex, on MCF-7 breast cancer cells through ROS-induced cell death.

BACKGROUND: Silver is a transition metal that is known to be less toxic than platinum. However, only few studies have reported the anticancer effects of some silver complexes and their possibility as an alternative to platinum complex. This study investigated the anticancer effects of the silver thiosulfate complex (STS), [Ag(S2O3)2]3-, consisting of silver and sodium thiosulfate. METHODS: In vitro cytotoxic activity of STS was investigated comparatively in human cancer cell lines (K562 and MCF-7) and normal human cells (mesenchymal stem cells and mammary epithelial cells). For its anticancer effects, cell cycle, mode of cell death, morphological changes, and accumulation of intracellular ROS and GSH were evaluated in MCF-7 to provide mechanistic insights. RESULTS: STS showed a concentration-dependent cytotoxicity in MCF-7 cell, which was abolished by pretreatment with N-acetylcysteine, suggesting ROS accumulation by STS. Moreover, STS caused cell cycle arrest at the G1 phase, decrease in the GSH levels, and morphological changes in MCF-7. Direct measurement of ROS demonstrated the elevation of intracellular ROS accumulation in cancer cells treated with STS; however, neither cytotoxicity nor ROS accumulation was observed in normal human cells. CONCLUSION: The results obtained here are the first evidence to show that STS exhibited an anticancer activity through ROS-induced mechanisms, and that its cytotoxicity is highly selective to cancer cells. The results of the present study warrant further investigation on the detailed mechanism of STS actions, as well as its in vivo effectiveness and safety for clinical application.

Nonlinear Disposition and Metabolic Interactions of Cannabidiol Through CYP3A Inhibition In Vivo in Rats.

Introduction: Cannabidiol (CBD) is known to affect the pharmacokinetics of other drugs through metabolic inhibition of CYP2C19 and CYP3A4. However, there is a lack of in vivo evidence for such drug interactions. Therefore, we investigated the saturability of CBD metabolism and CBD-drug interactions through inhibition of CYP3A in vivo. Materials and Methods: A nanoemulsion formulation of CBD (CBD-NE) was orally administered to rats at doses of 5, 10, 25, and 50 mg/kg, and plasma concentrations of CBD were measured by using liquid chromatography-tandem mass spectrometry (LC-MS/MS) to examine the dose-dependency of CBD exposure (area under the curve [AUC]). To examine the effect of a CYP3A inhibitor on CBD pharmacokinetics, rats were orally pretreated with 50 mg/kg ketoconazole (KCZ), a strong CYP3A inhibitor, before oral administration of CBD-NE at doses of 10 and 50 mg/kg, and plasma concentrations of CBD were measured using LC-MS/MS. Moreover, 13C-erythromycin was orally administered following administration of either NE (without CBD), as a control, or CBD-NE at 1, 10, and 50 mg/kg, and 13C-breath response was measured by using an infrared analyzer. Results: After administration of various doses of the nanoemulsified CBD formulation to rats, the exposure of CBD (i.e., the AUC calculated from the plasma concentration-time profile) increased in a greater than dose-proportional manner, especially at doses above 10 mg/kg. The AUC and maximum plasma concentration (Cmax) of CBD after oral administration of CBD-NE (10 mg/kg) increased approximately three times by the coadministration of KCZ. Moreover, according to the CBD-induced changes of 13C-breath response, the metabolism of 13C-erythromycin was shown to be inhibited by CBD at doses of 10 and 50 mg/kg, but not at 1 mg/kg. Conclusions: Nonlinear disposition and CYP-mediated drug interactions of CBD at doses exceeding 10 mg/kg were demonstrated for the first time in vivo in rats. Given the present results, it is proposed that caution for dose-dependent drug interactions should be considered for CBD.

Development of a Novel Nano-emulsion Formulation to Improve Intestinal Absorption of Cannabidiol.

BACKGROUND: Cannabidiol (CBD) is highly lipophilic, and its oral bioavailability is known to be very low in humans. In this study, we developed a novel nanoemulsion preparation of CBD (CBD-NE) to improve the poor solubility and absorption of CBD. The pharmacokinetic profiles of CBD in rats were evaluated after oral administrations of CBD oil and CBD-NE, and the effect of bile secretion on CBD absorption was also evaluated. METHODS: The CBD-NE formulation developed in this study consisted of vitamin E acetate, ethanol, Tween-20, and distilled water (1.7/3.8/70/24.5, w/w%). A CBD oil formulation (CBD oil, control) 100 mg/kg or CBD-NE 50 mg/kg was orally administered to rats, and the blood samples were collected over time. Moreover, the CBD oil or CBD-NE was orally administered to bile-fistulated rats, and the pharmacokinetic profiles of CBD were also evaluated. CBD concentrations in plasma were measured using LC-MS/MS. RESULTS: The particle size of CBD-NE was 35.3 ± 11.8 nm. Mean Tmax of CBD-NE was shortened significantly by the factor of 3 (from 8.00 to 2.40 h, p < 0.001) and AUC0-∞/dose increased by 65% (from 0.272 ± 0.045 to 0.448 ± 0.087 h L/kg) compared with CBD oil. AUC0-∞/dose and Cmax/dose after oral administration of CBD oil were significantly reduced by the factor of 27 and 23 (p < 0.05 and p < 0.01), respectively, in bile-fistulated rats compared with the untreated rats. In contrast, all pharmacokinetic parameters after oral administration of CBD-NE were not significantly different between the untreated and bile-fistulated rats. Therefore, these results demonstrated that conventional CBD oil formulation but not CBD-NE requires bile-mediated micelle formation. CONCLUSIONS: The novel NE formulation developed in this study successfully improved the absorption of CBD regardless of bile secretion. The newly developed oral CBD-NE preparation could be useful to achieve a more stable and quicker onset of action by CBD.

Sustained ß-AR stimulation induces synthesis and secretion of growth factors in cardiac myocytes that affect on cardiac fibroblast activation.

Paracrine factors, including growth factors and cytokines, released from cardiac myocytes following ß-adrenergic receptor (ß-AR) stimulation regulate cardiac fibroblasts. Activated cardiac fibroblasts have the ability to increase collagen synthesis, cell proliferation and myofibroblast differentiation, leading to cardiac fibrosis. However, it is unknown which ß-AR subtypes and signaling pathways mediate the upregulation of paracrine factors in cardiac myocytes. In this study, we demonstrated that sustained stimulation of ß-ARs significantly induced synthesis and secretion of growth factors, including connective tissue growth factor (CTGF) and vascular endothelial growth factor (VEGF), via the cAMP-dependent and protein kinase A (PKA)-dependent pathways. In addition, isoproterenol (ISO)-mediated synthesis and secretion of CTGF and VEGF through the ß1-AR and ß2-AR subtypes. Paracrine factors released by cardiac myocytes following sustained ß-AR stimulation are necessary for the induction of cell proliferation and synthesis of collagen I, collagen III and α-smooth muscle actin (α-SMA) in cardiac fibroblasts, confirming that ß-AR overstimulation of cardiac myocytes induces cardiac fibrosis by releasing several paracrine factors. These effects can be antagonized by ß-blockers, including atenolol, metoprolol, and propranolol. Thus, the use of ß-blockers may have beneficial effects on the treatment of myocardial fibrosis in patients with heart failure.

Comparison of adverse events following injection of original or generic docetaxel for the treatment of breast cancer.

PURPOSE: The approval of injectable generic drugs does not require bioequivalence testing. However, although generic products contain the same level of the active compound, the levels and types of additives present can differ from those used in the original product. Since docetaxel is highly lipophilic, polysorbate 80 (PS80), polyethylene glycol (PEG), and ethyl alcohol are employed to solubilize this anticancer agent. This retrospective study compared the safety of five docetaxel products (Taxotere®, Docetaxel Hospira, Docetaxel Sandoz, Docetaxel Sawai, and Docetaxel EE). METHODS: The incidence and severity of adverse events were analyzed using the medical records of operable breast cancer patients (n = 363) treated with docetaxel (75 mg/m2) in Showa University Hospital, Japan, from Jan 2013 to Mar 2016. Toxicities were graded using the Common Terminology Criteria for Adverse Events, version 4.0. RESULTS: Significant product-related differences were observed in the following non-hematological adverse events: injection site reaction (P = 0.0012), hand-foot syndrome (≥grade 3) (P = 0.0003), and oral mucositis (≥grade 3) (P = 0.0080). Multivariate logistic regression analyses of the associations between these adverse events and the total additive administered (g/m2) identified significant negative effects of PS80 and ethyl alcohol. CONCLUSIONS: Injectable docetaxel products had different adverse event profiles, which showed negative associations with the amounts of PS80 and ethyl alcohol present. This finding indicated that there might be additive-related pharmacokinetic and physiochemical differences among these products, suggesting a need for further pre- or post-approval testing of injectable generic products containing noticeable different levels of additives.

Hypoglycemic and Antioxidant Activities of the Water Extract of Aquilaria crassna Leaves in Streptozotocin-Nicotinamide-Induced Type-2 Diabetic Mice.

Antidiabetic effect of the water extract of Aquilaria crassna (A. crassna) leaves was recently claimed by some diabetic patients in Thailand, whereas its experimental evidence has not been published yet. The present study was therefore conducted to investigate pharmacological activities of the water extract of A. crassna leaves, focusing on its antioxidative and hypoglycemic effects in vitro and in vivo using streptozotocin (STZ)-nicotinamide (NA)-induced type 2 diabetic (DM) mice. An antioxidant activity of the herb extract was confirmed using a 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH) radical scavenging assay, and its IC50 on DPPH inhibition was determined to be 34.6 µg/mL. The extract also inhibited α-glucosidase in a concentration-dependent manner with the IC50 of 36.3 µg/mL. An enzyme-kinetic analysis using a Lineweaver-Burk plot indicated that the inhibition of α-glucosidase by the herb extract is an uncompetitive type with the inhibition constant (K(i)) of 39.8 µg/mL. An intragastric pretreatment of 1,000 mg/kg A. crassna in STZ-NA-induced type-2 DM significantly lowered the blood glucose at 30 and 60 min after an oral loading of 2 g/kg glucose (p < 0.05 and p < 0.01, respectively), as compared with the untreated-diabetic control. After 4 weeks-daily administration of 500 and 1,000 mg/kg A. crassna extract, the blood glucose levels were significantly reduced by about 66% and 86%, respectively, as compared with the untreated-diabetic control (p < 0.01). However, the expression of GLUT4 in skeletal muscle, detected by ELISA, was not significantly changed with the herb extract. In conclusion, our findings are the first to clearly demonstrate the hypoglycemic effects of A. crassna and to propose the α-glucosidase inhibition as an antidiabetic mechanism of the herb activity.