Determination of impurities in magnesium niobate by slurry introduction axially viewed inductively coupled plasma optical emission spectrometry.

A simple preparation scheme is described for the quantitative analysis of a magnesium niobate sample using slurry introduction axially viewed inductively coupled plasma optical emission spectrometry. Relationships between the stability of slurries and the conditions, such as particle size, pH, dispersant and amount of dispersant, were investigated experimentally. The MgNb(2)O(6) slurry sample was prepared by adding the dispersant sodium polyacrylate and agitation in an ultrasonic bath to ensure good dispersion. Under optimization of pH and amount of dispersant, an analysis of minor and trace impurities (Ba, Ca, Cr, Cu, Fe, Mn, Ni, Pb) in magnesium niobate was accomplished. Applying a paired t test, we showed that the results were in agreement at a 95% confidence level with the reference values obtained by a fusion method for a magnesium niobate sample, which verified that the calibration curves could be established by aqueous standards. Analytical results demonstrate that the factors that affected the accuracy of determination for MgNb(2)O(6) are mainly the particle size of the sample and the stability of slurry.

Steamed American ginseng berry: ginsenoside analyses and anticancer activities.

This study was designed to determine the changes in saponin content in American ginseng berries after treatment by heating and to assess the anticancer effects of the extracts. After steaming treatment (100-120 degrees C for 1 h, and 120 degrees C for 0.5-4 h), the content of seven ginsenosides, Rg1, Re, Rb1, Rc, Rb2, Rb3, and Rd, decreased; the content of five ginsenosides, Rh1, Rg2, 20R-Rg2, Rg3, and Rh2, increased. Rg3, a previously identified anticancer ginsenoside, increased significantly. Two hours of steaming at 120 degrees C increased the content of ginsenoside Rg3 to a greater degree than other tested ginsenosides. When human colorectal cancer cells were treated with 0.5 mg/mL steamed berry extract (120 degrees C 2 h), the antiproliferation effects were 97.8% for HCT-116 and 99.6% for SW-480 cells. At the same treatment concentration, the effects of unsteamed berry extract were 34.1% for HCT-116 and 4.9% for SW-480 cells. After staining with Hoechst 33258, apoptotic cells increased significantly by treatment with steamed berry extract compared with unheated extracts. Induction of apoptosis activity was confirmed by flow cytometry after staining with annexin V/PI. The steaming of American ginseng berries augments ginsenoside Rg3 content and increases the antiproliferative effects on two human colorectal cancer cell lines.

Antihyperglycemic effects of total ginsenosides from leaves and stem of Panax ginseng.

AIM: The antihyperglycemic effects of the total ginsenosides in Chinese ginseng (TGCG), extracted from leaves and the stem, were evaluated in diabetic C57BL/6J ob/ob mice. METHODS: Animals received daily intraperitoneal injections of TGCG (100 and 200 mg/kg) or oral administration (150 and 300 mg/kg) for 12 d. Fasting blood glucose levels and body weight were measured after fasting the animals for 4 h. Peripheral glucose use was also measured using an intraperitoneal glucose tolerance test. RESULTS: In the injection group, a high dose of TGCG (200 mg/kg) significantly lowered the fasting blood glucose levels in ob/ob mice on d 12 (153+/-16 mg/dL vs 203+/-9.8 mg/dL, P<0.01, compared to vehicle-treated group). In the oral group, blood glucose decreased notably with a dose of TGCG (300 mg/kg) on d 12 (169.1+/-12.6 mg/dL vs 211.6+/-13.8 mg/dL, P<0.05, compared to the vehicle-treated group). Glucose tolerance was also improved markedly in ob/ob mice. Furthermore, a significant reduction in bodyweight (P<0.05) was observed after 12 d of TGCG (300 mg/kg) treatment in mice from the oral group. CONCLUSION: The results indicated that in a diabetic ob/ob mouse model TGCG was endowed with significant anti-hyperglycemic and anti-obesity properties. Therefore, the total ginsenosides extracted from Chinese ginseng leaves and the stem may have some potential for treating diabetes.

Determination of major ginsenosides in Panax quinquefolius (American ginseng) using high-performance liquid chromatography.

In order to determine the active ingredients in root extracts of Panax quinquefolius (American ginseng), a gradient HPLC method involving UV photodiode array detection was applied to separate and quantify simultaneously the ginsenosides Rb1, Rb2, Rc, Rd, Re, Rf and Rg1. All ginseng saponins were baseline-resolved under the selected conditions, and the detection limits were 1.0 microg/mL or less. The method has been applied to analyse ginsenosides extracted from American ginseng cultivated in both Wisconsin and Illinois. Ginsenosides Re and Rb1 were the two main ginseng saponins in the root. The amounts of Re in 5- and 7-year Illinois-cultivated samples were greater than those found in ginseng cultivated for 3 or 4 years in Wisconsin, whereas the levels of Rb1 were greater in the younger Wisconsin samples.

American ginseng berry extract and ginsenoside Re attenuate cisplatin-induced kaolin intake in rats.

PURPOSE: Cisplatin, a chemotherapeutic agent, causes significant nausea and vomiting. It is postulated that cisplatin-induced oxidant stress may be responsible for these symptoms. We tested whether pretreatment with American ginseng berry extract (AGBE), an herb with potent antioxidant capacity, and one of its active antioxidant constituents, ginsenoside Re, could counter cisplatin-induced emesis using a rat pica model. METHODS: In rats, exposure to emetic stimuli such as cisplatin causes significant kaolin intake, a phenomenon called pica. We therefore measured cisplatin-induced kaolin intake as an indicator of the emetic response. Rats were pretreated with vehicle, AGBE (dose range 50-150 mg/kg, IP) or ginsenoside Re (2 and 5 mg/kg, IP). Rats were treated with cisplatin (3 mg/kg, IP) 30 min later. Kaolin intake, food intake, and body weight were measured every 24 h for 120 h. Additionally, the free radical scavenging activity of AGBE was measured in vitro using ESR spectroscopy. RESULTS: A significant dose-response relationship was observed between increasing doses of pretreatment with AGBE and reduction in cisplatin-induced pica. Kaolin intake was maximally attenuated by AGBE at a dose of 100 mg/kg. Food intake also improved significantly at this dose (P<0.05). Pretreatment with ginsenoside Re (5 mg/kg) also decreased kaolin intake (P<0.05). In vitro studies demonstrated a concentration-response relationship between AGBE and its ability to scavenge superoxide and hydroxyl radicals. CONCLUSION: Pretreatment with AGBE and its major constituent, Re, attenuated cisplatin-induced pica, and demonstrated potential for the treatment of chemotherapy-induced nausea and vomiting. Significant recovery of food intake further strengthens the conclusion that AGBE may exert an antinausea/antiemetic effect.

American ginseng leaf: ginsenoside analysis and hypoglycemic activity.

Previous studies showed that both American ginseng root and American ginseng berry extracts possess hypoglycemic properties. In this study, we investigated whether American ginseng leaves also have similar capabilities. We first analyzed the chemical constituents of American ginseng leaf and determined the content of six major ginsenosides, i.e., Rb(1), Rb(2), Rc, Rd, Re, and Rg(1), by high performance liquid chromatography (HPLC). Subsequently, we evaluated the hypoglycemic effect of American ginseng leaf extract (AGLE) in diabetic ob/ob adult mice. Animals received daily intraperitoneal injections of AGLE 50, 150 mg/kg or vehicle for 12 consecutive days. Fasting blood glucose levels, intraperitoneal glucose tolerance test (IPGTT), body weight and temperature were measured. On day 5, the 150 mg/kg AGLE group had significantly lower fasting blood glucose levels compared to vehicle-treated mice (223.0+/-13.9 mg/dl versus 258.0+/-14.0 mg/dl, P<0.05), while the blood glucose levels in 50 mg/kg group did not decrease significantly. On day 12, the glucose levels in both AGLE-treated groups were reduced significantly compared to vehicle group (180.0+/-10.0 mg/dl and 220.2+/-19.3 versus 268.0+/-10.0 mg/dl, P<0.01 and <0.05, respectively). IPGTT data showed that both AGLE 150 and 50 mg/kg groups significantly increased the glucose disposal on day 12 compared to the vehicle group. In addition, body weight decreased in ob/ob mice after AGLE treatment, and these body weight changes were accompanied by significant increases in body temperature (P<0.05). Our results suggest that AGLE possesses a significant anti-hyperglycemic and thermogenic activity and may prove to be beneficial in improving the management of type 2 diabetes.

Anti-diabetic effects of Gymnema yunnanense extract.

In this study, we evaluated anti-hyperglycemic effect and body weight reduction activity of Gymnema yunnanense extract in obese ob/ob and diabetic db/db mice. Animals received daily intraperitoneal injections of the extract 100 mg/kg for 12 days. On Day 5, the extract-treated ob/ob mice had significantly lower fasting blood glucose levels compared to vehicle-treated mice (161+/-14.5mg/dl versus 238+/-21.5mg/dl, P<0.01). On Day 12, the extract-treated ob/ob mice had normal fasting blood glucose levels, compared with vehicle-treated mice (119+/-3.3mg/dl versus 240+/-12.9 mg/dl, P<0.01). Glucose tolerance improved significantly. This was demonstrated by overall glucose excursion calculated as area under the curve (AUC) during the 2h intraperitoneal glucose tolerance test (IPGTT), which decreased by approximately 22% (P<0.01) compared to vehicle-treated ob/ob mice. In addition, extract-treated ob/ob mice lost weight significantly from 51.7+/-1.9 g on Day 0 to 45.7+/-1.2g on Day 12 (P<0.05 compared to vehicle-treated mice). In db/db mice, after treatment with same dose of the extract, fasting blood glucose levels also decreased significantly from Day 0 of 247+/-13.9 mg/dl to Day 5 of 172+/-7.5mg/dl and to Day 12 of 190+/-2.7 mg/dl (both P<0.01 compared to vehicle-treated group from Day 0 of 239+/-12.1mg/dl to Day 5 of 230+/-8.5mg/dl and Day 12 of 247+/-18.9 mg/dl, respectively). After 12 days of extract treatment, body weight in db/db mice reduced from 61.8+/-1.4 g on Day 0 to 59.8+/-1.1g on Day 12 (P<0.05). Our results support an in vivo anti-hyperglycemic and body weight reduction activity of G. yunnanense extract that may prove to be of clinical importance in improving the management of type 2 diabetes.

Kavalactones and dihydrokavain modulate GABAergic activity in a rat gastric-brainstem preparation.

Using an in vitro neonatal rat gastric-brainstem preparation, the activity of majority neurons recorded in the nucleus tractus solitarius (NTS) of the brainstem were significantly inhibited by GABA A receptor agonist, muscimol (30 microM), and this inhibition was reversed by selective GABA A receptor antagonist, bicuculline (10 microM). Application of kavalactones (300 microg/ml) and dihydrokavain (300 microM) into the brainstem compartment of the preparation also significantly reduced the discharge rate of these NTS neurons (39 % and 32 %, respectively, compared to the control level), and this reduction was partially reversed by bicuculline (10 microM). Kavalactones or dihydrokavain induced inhibitory effects were not reduced after co-application of saclofen (10 microM; a selective GABA B receptor antagonist) or naloxone (100 nM; an opioid receptor antagonist). Pretreatment with kavalactones (300 microg/ml) or dihydrokavain (300 microM) significantly decreased the NTS inhibitory effects induced by muscimol (30 microM), approximately from 51 % to 36 %. Our results demonstrated modulation of brainstem GABAergic mechanism by kavalactones and dihydrokavain, and suggested that these compounds may play an important role in regulation of GABAergic neurotransmission.

Determination of methylnaltrexone in clinical samples by solid-phase extraction and high-performance liquid chromatography for a pharmacokinetics study.

A high-performance liquid chromatographic (HPLC) method with electrochemical detection and solid-phase extraction (SPE) using cartridges of weak cation-exchange capacity as the primary retention mechanism is described for the separation and determination of methylnaltrexone (MNTX) in small clinical samples of plasma or urine. The procedure was performed using a Phenomenex Prodigy ODS-2, 5 microm, 150x3.2 mm analytical column and 50 mM potassium acetate buffer, with 11% methanol as organic modifier at pH* 4.5 at a flow-rate of 0.5 ml/min. The detection potential was 700 mV. The six-point standard calibration curves were linear over three consecutive days in the range from 2 to 100 ng/ml. The average goodness of fit (r) was 0.9993. The lower limit of detection (LOD) and limit of quantification (LOQ) were found to be 2.0 and 5.0 ng/ml, respectively. At the LOQ, the coefficient of variation for the entire method was 8.0% and the accuracy was 10.0% (n = 10). Recovery of the drug from plasma was in the region of 94%. The method was applied to a pharmacokinetics study of methylnaltrexone after subcutaneous administration and in numerous assays of analytes in blood plasma and urine. The pharmacokinetics parameters for a single dose of 0.1 or 0.3 mg/kg in plasma were C(max) = 110 (+/-55) and 287 (+/-101) ng/ml and t(max) = 16.7 (+/-10.8) and 20.0 (+/-9.5) min, respectively. The method is simple, yet sensitive for the detection and determination of methylnaltrexone in biological samples at the level of the physiological response.