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Background: Road traffic injuries (RTIs) are increasingly being recognized for their significant economic impact. Mozambique, like other low-income countries, suffers staggering rates of road traffic collisions. To our knowledge, this is the first study to estimate direct hospital costs of RTIs using a bottom-up, micro-costing approach in the Mozambican context. This study aims to calculate the direct, inpatient costs of RTIs in Mozambique and compare it to the financial capacity of the Mozambican public health care system., Methods: This was a retrospective, single-centre study. Charts of all patients with RTIs admitted to Maputo Central Hospital over a period of 2 months were reviewed. The costs were recorded and analysed based on direct costs, human resource costs, and overhead costs. Costs were calculated using a micro-costing approach., Results: In total, 114 patients were admitted and treated for RTIs at Maputo Central Hospital during June-July 2015. On average, the hospital cost per patient was US$ 604.28 (IQR 1033.58). Of this, 44% was related to procedural costs, 23% to diagnostic imaging costs, 17% to length-of-stay costs, 9% to medication costs, and 7% to laboratory test costs. The average annual inpatient cost of RTIs in Mozambique was almost US$ 116 million (0.8% of GDP)., Conclusion: The financial burden of RTIs in Mozambique represents approximately 40% of the annual public health care budget. These results help highlight the economic impact of trauma in Mozambique and the importance of an organized trauma system to reduce such costs.

In this study, we developed Different Artificial Intelligence (AI) models namely Artificial Neural Network (ANN), Adaptive Network based Fuzzy Inference System (ANFIS) and Support Vector Machine (SVM) for the prediction of Compression Coefficient of soil (Cc) which is one of the most important geotechnical parameters. A Monte Carlo approach was used for the sensitivity analysis of the AI models and input parameters. For the construction and validation of the models, 189 soft clayey soil samples were analyzed. In the models study, 13 input parameters: depth of sample, bulk density, plasticity index, moisture content, clay content, specific gravity, void ratio, liquid limit, dry density, porosity, plastic limit, degree of saturation, and liquidity index were used to obtain one output parameter "Cc". Validation of the models was done using statistical methods such as Mean Absolute Error (MAE), Root Mean Square Error (RMSE), and Coefficient of determination (R 2 ). Results of the model validation indicate that though performance of all the three models is good but SVM model is the best in the prediction of Cc. The Monte Carlo method based sensitivity analysis results show that out of the 13 input parameters considered for the models study, four parameters namely clay, degree of saturation, specific gravity and depth of sample are the most relevant in the prediction of Cc, and other parameters (bulk density, dry density, void ratio and porosity) are the most insignificant parameters for the prediction of Cc. Removal of these insignificant parameters helped to reduce the dimension of the input space and also model running time, and improved significantly the performance of the AI models. The results of this study might help in selecting the suitable AI models and input parameters for better and quick prediction of the Cc of soil., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Background: Approximately 5 billion people do not have access to safe, timely, and affordable surgical and anesthesia care, with this number disproportionately affecting those from low-middle-income countries (LMICs). Perioperative mortality rates (POMRs) have been identified by the World Health Organization as a potential health metric to monitor quality of surgical care provided. The purpose of this systematic review was to evaluate published reports of POMR and suggest recommendations for its appropriate use as a health metric., Methods: The protocol was registered a priori with PROSPERO. A peer-reviewed search strategy was developed adhering with the PRISMA guidelines. Relevant articles were identified through Medline, Embase, CENTRAL, CDSR, LILACS, PubMed, BIOSIS, Global Health, Africa-Wide Information, Scopus, and Web of Science databases. Two independent reviewers performed a primary screening analysis based on titles and abstracts, followed by a full-text screen. Studies describing POMRs of adult emergency abdominal surgeries in LMICs were included., Results: A total of 7787 articles were screened of which 7466 were excluded based on title and abstract. Three hundred and twenty-one articles entered full-text screen of which 70 articles met the inclusion criteria. Variables including timing of POMR reporting, intraoperative mortality, length of hospital stay, complication rates, and disease severity score were collected. Complication rates were reported in 83% of studies and postoperative stay in 46% of studies. 40% of papers did not report the specific timing of POMR collection. 7% of papers reported on intraoperative death. Additionally, 46% of papers used a POMR timing specific to the duration of their study. Vital signs were discussed in 24% of articles, with disease severity score only mentioned in 20% of studies., Conclusion: POMR is an important health metric for quantifications of quality of care of surgical systems. Further validation and standardization are necessary to effectively use this health metric.

Hereditary breast cancers, mainly due to BRCA1 and BRCA2 mutations, account for only 5-10% of this disease. The threshold for genetic testing is a 10% likelihood of detecting a mutation, as determined by validated models such as BOADICEA and Manchester Scoring System. A 90-95% reduction in breast cancer risk can be achieved with bilateral risk-reducing mastectomy in unaffected BRCA mutation carriers. In patients with BRCA-associated breast cancer, there is a 40% risk of contralateral breast cancer and hence risk-reducing contralateral mastectomy is recommended, which can be performed simultaneously with surgery for unilateral breast cancer. Other options for risk management include surveillance by mammogram and breast magnetic resonance imaging, and chemoprevention with hormonal agents. With the advent of next-generation sequencing and development of multigene panel testing, the cost and time taken for genetic testing have reduced, making it possible for treatment-focused genetic testing. There are also drugs such as the PARP inhibitors that specifically target the BRCA mutation. Risk management multidisciplinary clinics are designed to quantify risk, and offer advice on preventative strategies. However, such services are only possible in high-income settings. In low-resource settings, the prohibitive cost of testing and the lack of genetic counsellors are major barriers to setting up a breast cancer genetics service. Family history is often not well documented because of the stigma associated with cancer. Breast cancer genetics services remain an unmet need in low- and middle-income countries, where the priority is to optimise access to quality treatment.

Groundwater vulnerability assessment is a measure of potential groundwater contamination for areas of interest. The main objective of this study is to modify original DRASTIC model using four objective methods, Weights-of-Evidence (WOE), Shannon Entropy (SE), Logistic Model Tree (LMT), and Bootstrap Aggregating (BA) to create a map of groundwater vulnerability for the Sari-Behshahr plain, Iran. The study also investigated impact of addition of eight additional factors (distance to fault, fault density, distance to river, river density, land-use, soil order, geological time scale, and altitude) to improve groundwater vulnerability assessment. A total of 109 nitrate concentration data points were used for modeling and validation purposes. The efficacy of the four methods was evaluated quantitatively using the Area Under the Receiver Operating Characteristic (ROC) Curve (AUC). AUC value for original DRASTIC model without any modification of weights and rates was 0.50. Modification of weights and rates resulted in better performance with AUC values of 0.64, 0.65, 0.75, and 0.81 for BA, SE, LMT, and WOE methods, respectively. This indicates that performance of WOE is the best in assessing groundwater vulnerability for DRASTIC model with 7 factors. The results also show more improvement in predictability of the WOE model by introducing 8 additional factors to the DRASTIC as AUC value increased to 0.91. The most effective contributing factor for ground water vulnerability in the study area is the net recharge. The least effective factors are the impact of vadose zone and hydraulic conductivity., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Floods are one of the most damaging natural hazards causing huge loss of property, infrastructure and lives. Prediction of occurrence of flash flood locations is very difficult due to sudden change in climatic condition and manmade factors. However, prior identification of flood susceptible areas can be done with the help of machine learning techniques for proper timely management of flood hazards. In this study, we tested four decision trees based machine learning models namely Logistic Model Trees (LMT), Reduced Error Pruning Trees (REPT), Naïve Bayes Trees (NBT), and Alternating Decision Trees (ADT) for flash flood susceptibility mapping at the Haraz Watershed in the northern part of Iran. For this, a spatial database was constructed with 201 present and past flood locations and eleven flood-influencing factors namely ground slope, altitude, curvature, Stream Power Index (SPI), Topographic Wetness Index (TWI), land use, rainfall, river density, distance from river, lithology, and Normalized Difference Vegetation Index (NDVI). Statistical evaluation measures, the Receiver Operating Characteristic (ROC) curve, and Freidman and Wilcoxon signed-rank tests were used to validate and compare the prediction capability of the models. Results show that the ADT model has the highest prediction capability for flash flood susceptibility assessment, followed by the NBT, the LMT, and the REPT, respectively. These techniques have proven successful in quickly determining flood susceptible areas., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Background: The focus of this study was to assess the accuracy of breast MRI in predicting pathologic tumor size in invasive lobular carcinoma (ILC) and to evaluate the incidence and factors associated with the detection of additional MRI lesions in ILC patients., Study Design: We retrospectively reviewed data from patients with stage I to III ILC diagnosed between 2010 and 2016 at our institution. Univariable and multivariable logistic regression were used to determine factors associated with detection of additional suspicious lesions on MRI., Results: The cohort included 99 women with ILC who underwent preoperative MRI, with a median age of 61 years (range 35 to 80 years). The sensitivity of MRI for detecting invasive lobular carcinoma was 99%, higher than that of mammography (68%) and ultrasound (92%). Mammography and ultrasound had a tendency to underestimate ILC, and MRI estimates of final tumor size were concordant in the majority (58.6%) of cases, with a median discordance of -2 mm. Magnetic resonance imaging detected additional ipsilateral malignancy in 23.2%, occult contralateral disease in 3.0%, and altered surgical management in 29.3% of ILC cases. In multivariable analyses, factors significantly associated with additional suspicious findings on MRI included higher breast density (odds ratio 3.19; 95% CI 1.01 to 10.0) and lymph node-positive disease (odds ratio 4.02; 95% CI 0.96 to 16.9)., Conclusions: Preoperative MRI is a useful adjunct to conventional breast imaging in ILC, particularly in women with dense breast tissue., (Copyright © 2018 American College of Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: Women diagnosed with lobular carcinoma in situ (LCIS) have a 3-fold to 10-fold increased risk of developing invasive breast cancer. The objective of this study was to evaluate the life expectancy (LE) and differences in survival offered by active surveillance, risk-reducing chemoprevention, and bilateral prophylactic mastectomy among women with LCIS., Methods: A Markov simulation model was constructed to determine average LE and quality-adjusted LE (QALE) gains for hypothetical cohorts of women diagnosed with LCIS at various ages under alternative risk-reduction strategies. Probabilities for invasive breast cancer, breast cancer-specific mortality, other-cause mortality and the effectiveness of preventive strategies were derived from published studies and from the National Cancer Institute's Surveillance, Epidemiology, and End Results database., Results: Assuming a breast cancer incidence from 1.02% to 1.37% per year under active surveillance, a woman aged 50 years diagnosed with LCIS would have a total LE of 32.78 years and would gain 0.13 years (1.6 months) in LE by adding chemoprevention and 0.25 years (3.0 months) in LE by adding bilateral prophylactic mastectomy. After quality adjustment, chemoprevention resulted in the greatest QALE for women ages 40 to 60 years at LCIS diagnosis, whereas surveillance remained the preferred strategy for optimizing QALE among women diagnosed at age 65 years and older., Conclusions: In this model, among women with a diagnosis of LCIS, breast cancer prevention strategies only modestly affected overall survival, whereas chemoprevention was modeled as the preferred management strategy for optimizing invasive disease-free survival while prolonging QALE form women younger than 65 years. Cancer 2017;123:2609-17. © 2017 American Cancer Society., (© 2017 American Cancer Society.)

Following our interest in new diterpene glycosides with better taste profiles than that of Rebaudioside M, we have recently isolated and characterized Rebaudioside IX-a novel steviol glycoside-from a commercially-supplied extract of Stevia rebaudiana Bertoni. This molecule contains a hexasaccharide group attached at C-13 of the central diterpene core, and contains three additional glucose units when compared with Rebaudioside M. Here we report the complete structure elucidation-based on extensive Nuclear Magnetic Resonance (NMR) analysis (1H, 13C, Correlation Spectroscopy (COSY), Heteronuclear Single Quantum Coherence-Distortionless Enhancement Polarization Transfer (HSQC-DEPT), Heteronuclear Multiple Bond Correlation (HMBC), 1D Total Correlation Spectroscopy (TOCSY), Nuclear Overhauser Effect Spectroscopy (NOESY)) and mass spectral data-of this novel diterpene glycoside with nine sugar moieties and containing a relatively rare 16 α-linked glycoside. A steviol glycoside bearing nine glucose units is unprecedented in the literature, and could have an impact on the natural sweetener catalog.

The safety of steviol glycosides is based on data available on several individual steviol glycosides and on the terminal absorbed metabolite, steviol. Many more steviol glycosides have been identified, but are not yet included in regulatory assessments. Demonstration that these glycosides share the same metabolic fate would indicate applicability of the same regulatory paradigm. In vitro incubation assays with pooled human fecal homogenates, using rebaudiosides A, B, C, D, E, F and M, as well as steviolbioside and dulcoside A, at two concentrations over 24-48 h, were conducted to assess the metabolic fate of various steviol glycoside classes and to demonstrate that likely all steviol glycosides are metabolized to steviol. The data show that glycosidic side chains containing glucose, rhamnose, xylose, fructose and deoxy-glucose, including combinations of α(1-2), β-1, β(1-2), β(1-3), and β(1-6) linkages, were degraded to steviol mostly within 24 h. Given a common metabolite structure and a shared metabolic fate, safety data available for individual steviol glycosides can be used to support safety of purified steviol glycosides in general. Therefore, steviol glycosides specifications adopted by the regulatory authorities should include all steviol glycosides belonging to the five groups of steviol glycosides and a group acceptable daily intake established., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Object: The Brain Trauma Foundation has published guidelines on the surgical management of traumatic subdural hematoma (SDH). However, no data exist on the proportion of patients with SDH that can be selected for conservative management and what is the outcome of these patients. The goals of this study were as follows: 1) to establish what proportion of patients are initially treated conservatively; 2) to determine what proportion of patients will deteriorate and require surgical evacuation; and 3) to identify risk factors associated with deterioration and delayed surgery., Methods: All cases of acute traumatic SDH (869 when inclusion criteria were met) presenting over a 4-year period were reviewed. For all conservatively treated SDH, the proportion of delayed surgical intervention and the Glasgow Outcome Scale score were taken as outcome measures. Multiple factors were compared between patients who required delayed surgery and patients without surgery., Results: Of the 869 patients with acute traumatic SDH, 646 (74.3%) were initially treated conservatively. A good outcome was achieved in 76.7% of the patients. Only 6.5% eventually required delayed surgery, and the median delay for surgery was 9.5 days. Factors associated with deterioration were as follows: 1) thicker SDH (p<0.001); 2) greater midline shift (p<0.001); 3) location at the convexity (p=0.001); 4) alcohol abuse (p=0.0260); and 5) history of falls (p=0.018). There was no significant difference in regard to age, sex, Glasgow Coma Scale score, Injury Severity Score, abnormal coagulation, use of blood thinners, and presence of cerebral atrophy or white matter disease., Conclusions: The majority of patients with SDH are treated conservatively. Of those, only 6.5% later required surgery, for raised intracranial pressure or SDH progression. Patients at risk can be identified and followed more carefully.

In a continued search for novel diterpenoid glycosides, we recently isolated and characterized a Rebaudioside M derivative with a hydroxyl group at position 15 in the central diterpene core from an extract of Stevia rebaudiana Bertoni. Here we report the complete structure elucidation of 15α-hydroxy-Rebaudioside M (2) on the basis of NMR (1H, 13C, COSY, HSQC-DEPT, HMBC, 1D TOCSY, NOESY) and mass spectral data. Steviol glycoside with a hydroxyl group at C-15 in the central diterpene core has not been previously reported.

A natural sweetener, Rubusoside (1), subjected to extreme pH and temperature conditions, resulted in the isolation and structural elucidation of one novel rubusoside degradant (7), together with seven known degradants (2-6 and 8-9). ID and 2D NMR spectroscopy (1H, 13C, COSY, HSQC-DEPT, HMBC, and NOESY) and mass spectral data were used to fully characterize the degradant 7.

A 67-year-old woman was admitted with signs and symptoms of Graves thyrotoxicosis. Biochemistry results were as follows: TSH was undetectable; FT4 was >6.99 ng/dL (0.7-1.8); FT3 was 18 pg/mL (3-5); TSI was 658% (0-139). Thyroid uptake and scan showed diffusely increased tracer uptake in the thyroid gland. The patient was started on methimazole 40 mg BID, but her LFTs elevated precipitously with features of fulminant hepatitis. Methimazole was determined to be the cause and was stopped. After weighing pros and cons, lithium was initiated to treat her persistent thyrotoxicosis. Lithium 300 mg was given daily with a goal to maintain between 0.4 and 0.6. High dose Hydrocortisone and propranolol were also administered concomitantly. Free thyroid hormone levels decreased and the patient reached a biochemical and clinical euthyroid state in about 8 days. Though definitive RAI was planned, the patient has been maintained on lithium for more than a month to control her hyperthyroidism. Trial removal of lithium results in reemergence of thyrotoxicosis within 24 hours. Patient was maintained on low dose lithium treatment with lithium level just below therapeutic range which was sufficient to maintain euthyroid state for more than a month. There were no signs of lithium toxicity within this time period. Conclusion. Lithium has a unique physiologic profile and can be used to treat thyrotoxicosis when thionamides cannot be used while awaiting elective radioablation. Lithium levels need to be monitored; however, levels even at subtherapeutic range may be sufficient to treat thyrotoxicosis.

Four new minor diterpene glycosides with a rare α-glucosyl linkage were isolated from a cyclodextrin glycosyltransferase glucosylated stevia extract containing more than 98% steviol glycosides. The new compounds were identified as 13-[(2-O-β-D-glucopyranosyl-3-O-(4-O-α-D-glucopyranosyl)-β-D-glucopyranosyl-β-D-glucopyranosyl)oxy] ent-kaur-16-en-19-oic acid-[(4-O-α-D-glucopyranosyl-β-D-glucopyranosyl) ester] (1), 13-[(2-O-β-D-glucopyranosyl-β-D-glucopyranosyl)oxy] ent-kaur-16-en-19-oic acid-[(4-O-(4-O-(4-O-α-D-glucopyranosyl)-α-D-glucopyranosyl)-α-D-glucopyranosyl)-β-D-glucopyranosyl ester] (2), 13-[(2-O-β-D-glucopyranosyl-3-O-(4-O-(4-O-(4-O-α-D-glucopyranosyl)-α-D-glucopyranosyl)-α-D-glucopyranosyl)-β-D-glucopyranosyl-β-D-glucopyranosyl)oxy] ent-kaur-16-en-19-oic acid β-D-glucopyranosyl ester (3), and 13-[(2-O-β-D-glucopyranosyl-3-O-(4-O-(4-O-(4-O-α-D-glucopyranosyl)-α-D-glucopyranosyl)-α-D-glucopyranosyl)-β-D-glucopyranosyl- β-D-glucopyranosyl)oxy] ent-kaur-16-en-19-oic acid-[(4-O-α-D-glucopyranosyl-β-D-glucopyranosyl) ester] (4) on the basis of extensive NMR and mass spectral (MS) data as well as hydrolysis studies.

To supply the increasing demand of natural high potency sweeteners to reduce the calories in food and beverages, we have looked to steviol glycosides. In this work we report the bioconversion of rebaudioside A to rebaudioside I using a glucosyltransferase enzyme. This bioconversion reaction adds one sugar unit with a 1→3 linkage. We utilized 1D and 2D NMR spectroscopy (1H, 13C, COSY, HSQC-DEPT, HMBC, 1D TOCSY and NOESY) and mass spectral data to fully characterize rebaudioside I.

We report the isolation and complete structure of an isomer of rebaudioside D, known as rebaudioside D2. This novel steviol glycoside was isolated from a bioconversion reaction of rebaudioside A to rebaudioside D. Rebaudioside D2 possesses a relatively rare 1 --> 6 sugar linkage, which was discovered by extensive analysis of NMR (1H, 13C, COSY, HSQC-DEPT, HMBC, 1D TOCSY and NOESY) and mass spectral data.

A minor product, rebaudioside M2 (2), from the bioconversion reaction of rebaudioside A (4) to rebaudioside D (3), was isolated and the complete structure of the novel steviol glycoside was determined. Rebaudioside M2 (2) is considered an isomer of rebaudioside M (1) and contains a relatively rare 1→6 sugar linkage. It was isolated and characterized with NMR (1H, 13C, COSY, HSQC-DEPT, HMBC, 1D-TOCSY, and NOESY) and mass spectral data. Additionally, we emphasize the importance of 1D and 2D NMR techniques when identifying complex steviol glycosides. Numerous NMR spectroscopy studies of rebaudioside M (1), rebaudioside D (3), and mixture of 1 and 3 led to the discovery that SG17 which was previously reported in literature, is a mixture of rebaudioside D (3), rebaudioside M (1), and possibly other related steviol glycosides.

Continuous phytochemical studies of the crude extract of Luo Han Guo (Siraitia grosvenorii) furnished three additional new cucurbitane triterpene glycosides, namely 11-deoxymogroside V, 11-deoxyisomogroside V, and 11-deoxymogroside VI. The structures of all the isolated compounds were characterized on the basis of extensive NMR and mass spectral data as well as hydrolysis studies. The complete ¹H- and ¹³C-NMR spectral assignments of the three unknown compounds are reported for the first time based on COSY, TOCSY, HSQC, and HMBC spectroscopic data.

This work aims to review and showcase the unique properties of rebaudioside M as a natural non-caloric potential sweetener in food and beverage products. To determine the potential of rebaudioside M, isolated from Stevia rebaudiana Bertoni, as a high potency sweetener, we examined it with the Beidler Model. This model estimated that rebaudioside M is 200-350 times more potent than sucrose. Numerous sensory evaluations of rebaudioside M's taste attributes illustrated that this steviol glycoside possesses a clean, sweet taste with a slightly bitter or licorice aftertaste. The major reaction pathways in aqueous solutions (pH 2-8) for rebaudioside M are similar to rebaudioside A. Herein we demonstrate that rebaudioside M could be of great interest to the global food industry because it is well-suited for blending and is functional in a wide variety of food and beverage products.

Degradation of rebaudioside M, a minor sweet component of Stevia rebaudiana Bertoni, under conditions that simulated extreme pH and temperature conditions has been studied. Thus, rebaudioside M was treated with 0.1 M phosphoric acid solution (pH 2.0) and 80 °C temperature for 24 h. Experimental results indicated that rebaudioside M under low pH and higher temperature yielded three minor degradation compounds, whose structural characterization was performed on the basis of 1D (1H-, 13C-) & 2D (COSY, HSQC, HMBC) NMR, HRMS, MS/MS spectral data as well as enzymatic and acid hydrolysis studies.

From the extract of the leaves of Stevia rebaudiana Bertoni, a diterpene glycoside was isolated which was identified as 13-[(2-O-beta-D-glucopyranosyl-3-O-beta-D-glucopyranosyl-beta-D-glucopyranosyl)oxy] ent-kaur-16-en-19-oic acid-(2-O-beta-D-glucopyranosyl-3-O-beta-D-glucopyranosyl-D-glucopyranosyl) ester (1). The complete 1H and 13C NMR assignment of 1 is reported for the first time, from extensive NMR (1H and 13C, COSY, HSQC, and HMBC) and mass spectral data. Also, we report the sensory evaluation of 1 against sucrose for the sweetness property of this molecule.

Two additional novel minor diterpene glycosides were isolated from the commercial extract of the leaves of Stevia rebaudiana Bertoni. The structures of the new compounds were identified as 13-{β-D-glucopyranosyl-(1 → 2)-O-[β-D-glucopyranosyl-(1 → 3)-β-D-glucopyranosyl-oxy} ent-kaur-16-en-19-oic acid {β-D-xylopyranosyl-(1 → 2)-O-[β-D-glucopyranosyl-(1 → 3)]-O-β-D-glucupyranosyl-ester} (1), and 13-{β-D-6-deoxy-glucopyranosyl-(1 → 2)-O-[β-D-glucopyranosyl-(1 → 3)-β-D-glucopyranosyl-oxy} ent-kaur-16-en-19-oic acid {β-D-glucopyranosyl-(1 → 2)-O-[β-D-glucopyranosyl-(1 → 3)-β-D-gluco-pyranosyl-ester} (2), on the basis of extensive 1D (1H- and 13C-) 2D NMR (COSY, HSQC and HMBC) and MS spectroscopic data as well as chemical studies.

Catalytic hydrogenation of the exocyclic double bond present between C16 and C17 carbons of the four ent-kaurane diterpene glycosides namely rebaudioside A, rebaudioside B, rebaudioside C, and rebaudioside D isolated from Stevia rebaudiana has been carried out using Pt/C, Pd(OH)2, Rh/C, Raney Ni, PtO2, and 5% Pd/BaCO3 to their corresponding dihydro derivatives with 17α and 17β methyl group isomers. Reactions were performed using the above-mentioned catalysts with the solvents methanol, water, and ethanol/water (8:2) under various conditions. Synthesis of reduced steviol glycosides was performed using straightforward chemistry and their structures were characterized on the basis of 1D and 2D NMR spectral data, including a comparison with reported spectral data.

Catalytic hydrogenation of rebaudioside B, rebaudioside C, and rebaudioside D; the three ent-kaurane diterpene glycosides isolated from Stevia rebaudiana was carried out using Pd(OH)(2). Reduction of steviol glycosides was performed using straightforward synthetic chemistry with the catalyst Pd(OH)(2) and structures of the corresponding dihydro derivatives were characterized on the basis of 1D and 2D nuclear magnetic resonance (NMR) spectral data indicating that all are novel compounds being reported for the first time. Also, the taste properties of all reduced compounds were evaluated against their corresponding original steviol glycosides and sucrose.

Catalytic hydrogenation of the three ent-kaurane diterpene glycosides isolated from Stevia rebaudiana, namely rubusoside, stevioside, and rebaudioside-A has been carried out using Pd(OH)₂ and their corresponding dihydro derivatives have been isolated as the products. Synthesis of reduced steviol glycosides was performed using straightforward chemistry and their structures were characterized on the basis of 1D and 2D NMR spectral data and chemical studies. Also, we report herewith the sensory evaluation of all the reduced compounds against their corresponding original steviol glycosides and sucrose for the sweetness property of these molecules.

The structure activity relationship between the C₁₆-C₁₇ methylene double bond on the aglycone of steviol glycosides and the corresponding impact on their sweet taste has been reported here for the first time. It has been observed that converting stevioside and rebaudioside A to their corresponding ketones by switching the doubly bonded methylene on C-17 for a ketone group actually removes the sweet taste properties of these molecules completely. Regenerating the original molecules tends to restore the sweet taste of both the steviol glycosides. Thus this C₁₆-C₁₇ methylene double bond in rebaudioside A and stevioside can be regarded as a pharmacophore essential for the sweetness property of these molecules.

For a new sweetness technology to realize strong commercial success, it must be safe, exhibit good taste quality, be sufficiently soluble and stable in food and beverage systems, and be cost effective and patentable. Assessments of the commercial promise of eight synthetic and eight natural non-caloric sweeteners are made relevant to these metrics. High-potency (HP) non-caloric sweeteners, both synthetic and natural, are generally limited in taste quality by (a) low maximal sweetness response, (b) "off" tastes, (c) slow-onset sweet tastes that linger, and (d) sweet tastes that adapt or desensitize the gustatory system. Formulation approaches to address these limitations are discussed. Enhancement of the normal sucrose sensory response by action of a sweetener receptor positive allosteric modulator (PAM) has been achieved with very significant calorie reduction and with retention of the taste quality of sucrose. Research on PAM discovery over the past decade is summarized.

Synthesis of two ent-kaurane diterpene glycosides, steviol 19-O-β-D-glucopyranosiduronic acid (steviol glucuronide, 5), and 13-hydroxy ent-kaur-16-en-19-oic acid-β-D-glucopyranosyl ester (7) has been achieved from a common starting material, steviol, using phase transfer catalyst. Also, synthesis of an additional 17-nor-ent-kaurane glycoside, namely 13-methyl-16-oxo-17-nor-ent-kauran-19-oic acid-β-D-glucopyranosyl ester (10) was performed using the starting material isosteviol and similar synthetic methodology. Synthesis of all three steviol glycosides was performed using straightforward chemistry and their structures were characterized on the basis of 1D and 2D NMR as well as mass spectral (MS) data.

From the commercial extract of the leaves of Stevia rebaudiana, two new minor diterpene glycosides having α-glucosyl linkage were isolated besides the known steviol glycosides including stevioside, steviolbioside, rebaudiosides A-F, rubusoside and dulcoside A. The structures of the two compounds were identified as 13-[(2-O-(3-α-O-d-glucopyranosyl)-β-d-glucopyranosyl-3-O-β-d-glucopyranosyl-β-d-glucopyranosyl)oxy] ent-kaur-16-en-19-oic acid β-d-glucopyranosyl ester (1), and 13-[(2-O-β-d-glucopyranosyl-3-O-(4-O-α-d-glucopyranosyl)-β-d-glucopyranosyl-β-d-glucopyranosyl)oxy] ent-kaur-16-en-19-oic acid β-d-glucopyranosyl ester (2), on the basis of extensive NMR and MS spectral data as well as chemical studies., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

From the commercial extract of the leaves of Stevia rebaudiana, two additional new diterpenoid glycosides were isolated and their structures were characterized as 13-[(2-O-beta-glucopyranosyl-3-O-beta-D-xylopyranosyl-beta-D-glucopyranosyl)oxy] ent-kaur-16-en-19-oic acid beta-D-glucopyranosyl ester (1) and 13-[(2-O-beta-D-xylopyranosyl-beta-D-glucopyranosyl)oxy] ent-kaur-16-en-19-oic acid beta-D-glucopyranosyl ester (2) on the basis of extensive spectral data (NMR and MS) and chemical studies.

From the commercial extract of the leaves of Stevia rebaudiana, two new diterpenoid glycosides were isolated besides the known steviol glycosides including stevioside, rebaudiosides A-F, rubusoside, and dulcoside A. The structures of the two new compounds were identified as 13-[(2-O-6-deoxy-β-d-glucopyranosyl-β-d-glucopyranosyl)oxy] ent-kaur-16-en-19-oic acid β-d-glucopyranosyl ester (1), and 13-[(2-O-6-deoxy-β-d-glucopyranosyl-3-O-β-d-glucopyranosyl-β-d-glucopyranosyl)oxy] ent-kaur-16-en-19-oic acid β-d-glucopyranosyl ester (2), on the basis of extensive NMR and MS spectral data as well as chemical studies., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Three novel diterpene glycosides were isolated for the first time from the commercial extract of the leaves of Stevia rebaudiana, along with several known steviol glycosides, namely stevioside, rebaudiosides A-F, rubusoside and dulcoside A. The new compounds were identified as 13-[(2-O-β-D-glucopyranosyl-3-O-β-D-glucopyranosyl-β-D-glucopyranosyl)oxy] ent-kaur-15-en-19-oic acid, 13-[(2-O-β-D-glucopyranosyl-3-O-β-D-glucopyranosyl-β-D-glucopyranosyl)oxy]-16β-hydroxy-ent-kauran-19-oic acid and 13-methyl-16-oxo-17-nor-ent-kauran-19-oic acid-β-D-glucopyranosyl ester on the basis of extensive 2D NMR and MS spectroscopic data as well as chemical studies.

From the commercial extract of the leaves of Stevia rebaudiana, a new diterpene glycoside was isolated besides the known steviol glycosides including stevioside, rebaudiosides A-F, rubusoside and dulcoside A. The new compound was identified as 13-[(2-O-β-D-glucopyranosyl-3-O-β-D-glucopyranosyl-β-D-glucopyranosyl)oxy] ent-kaur-16-en-19-oic acid-(2-O-α-L-rhamnopyranosyl-β-D-glucopyranosyl) ester (1) on the basis of extensive spectroscopic (NMR and MS) and chemical studies.

Two new new diterpene glycosides, 13-[(2-O-(6-O-beta-D-glucopyranosyl)-beta-D-glucopyranosyl-beta-D-glucopyranosyl)oxy] kaur-16-en-18-oic acid beta-D-glucopyranosyl ester (1) and 13-[(2-O-beta-D-glucopyranosyl-3-O-beta-D-fructofuranosyl-beta-D-glucopyranosyl)oxy] kaur-16-en-18-oic acid beta-D-glucopyranosyl ester (2) were isolated from the leaves of Stevia rebaudiana, along with the known steviol glycosides stevioside, rebaudiosides A-F and dulcoside A. The structures of the two new compounds were established on the basis of extensive 2D NMR (COSY, HSQC, and HMBC), MS and chemical studies.

Steviol glycosidesrebaudioside (reb) A, C and D have low aqueous solubilities. To improve their aqueous solubilities, inclusion complex of steviol glycosides, reb A, C and D and gamma cyclodextrin were prepared by freeze drying method and further characterized by means of differential scanning calorimetry, Fourier transform infrared spectroscopy and Raman spectroscopy. The effect of gamma cyclodextrin on chemical shifts of the steviol glycosides was also studied in proton NMR experiments as well as in solid state (13)C CP/MAS NMR experiments. These results indicated that the steviol glycosides were clearly in inclusion complex formation with the gamma cyclodextrin which also results in solubility enhancement of these steviol glycosides. Phase solubility studies showed that amounts of soluble reb A, C and D increased with increasing amounts of gamma cyclodextrin indicating formation of 1:1 stoichiometric and higher order inclusion complexes.

This paper reports the first study of the gas-phase intramolecular elimination reaction of steviol glycosides in positive electrospray mass spectrometry. The observed glycosylated product ions are proposed to be formed via an intramolecular elimination of sugar units from the parent molecule ion. It was further proven by MS/MS studies and deuterium labeling experiments with one of the steviol glycosides, rebaudioside A. These mass spectrometric results confirmed that the new glycosylated product ions observed are most likely formed by the combination of glucose moieties (Glu) II-IV and Glu I via a gas-phase intramolecular elimination reaction.

The Coca-Cola Company and Cargill, Inc. have initiated the development and commercialization of the Stevia rebaudiana (Bertoni) derived sweetener rebaudioside A. Efforts were focused on high purity rebaudioside A (>97% by HPLC), commonly known as rebiana. In the course of the development program, extensive stability studies were carried out on rebiana, all supporting good stability for use in all food and beverage applications, including conditions where rebiana-sweetened beverages were exposed to light. Our findings on rebiana light stability refute those of an earlier study that suggested rebaudioside A to be unstable to sunlight exposure, while the structurally homologous stevioside is stable. We replicated the earlier study and found no significant photodegradation for either rebaudioside A or stevioside.

Rebiana is the common name for high-purity rebaudioside A, a natural non-calorie sweetener 200-300 times more potent than sucrose. It provides zero calories and has a clean, sweet taste with no significant undesirable taste characteristics. It is functional in a wide array of beverages and foods and can be blended with other non-calorie or carbohydrate sweeteners. It is stable under dry conditions, and has much better stability than aspartame or neotame in aqueous food systems. Studies undertaken for the development of a purification process and for the full characterization of the properties of rebiana are reported here.

This randomized, double-blind, cross-over study assessed the comparative pharmacokinetics of steviol and steviol glucuronide following single oral doses of rebaudioside A and stevioside in healthy adult male subjects. Steviol glucuronide appeared in the plasma of all subjects after administration of rebaudioside A or stevioside, with median tmax values of 12.0 and 8.00h post-dose, respectively. Steviol glucuronide was eliminated from the plasma, with similar t1/2 values of approximately 14h for both compounds. Administration of rebaudioside A resulted in a significantly (approximately 22%) lower steviol glucuronide geometric mean Cmax value (1472ng/mL) than administration of stevioside (1886ng/mL). The geometric mean AUC0-t value for steviol glucuronide after administration of rebaudioside A (30,788ngh/mL) was approximately 10% lower than after administration of stevioside (34,090ngh/mL). Steviol glucuronide was excreted primarily in the urine of the subjects during the 72h collection period, accounting for 59% and 62% of the rebaudioside A and stevioside doses, respectively. No steviol glucuronide was detected in feces. Pharmacokinetic analysis indicated that rebaudioside A and stevioside underwent similar metabolic and elimination pathways in humans with steviol glucuronide excreted primarily in the urine and steviol in the feces. No safety concerns were noted as determined by reporting of adverse events, laboratory assessments of safety or vital signs.

Although most drugs are formulated in the crystalline state, amorphous or other crystalline forms are often generated during the formulation process. The presence of other forms can dramatically affect the physical and chemical stability of the drug. The identification and quantitation of different forms of a drug is a significant analytical challenge, especially in a formulated product. The ability of solid-state 13C NMR spectroscopy with cross polarization (CP) and magic-angle spinning (MAS) to quantify the amounts of three of the multiple crystalline and amorphous forms of the artificial sweetener neotame is described. It was possible to quantify, in a mixture of two anhydrous polymorphic forms of neotame, the amount of each polymorph within 1-2%. In mixtures of amorphous and crystalline forms of neotame, the amorphous content could be determined within 5%. It was found that the crystalline standards that were used to prepare the mixtures were not pure crystalline forms, but rather a mixture of crystalline and amorphous forms. The effect of amorphous content in the crystalline standards on the overall quantitation of the two crystalline polymorphic forms is discussed. The importance of differences in relaxation parameters and CP efficiencies on quantifying mixtures of different forms using solid-state NMR spectroscopy is also addressed., ((c) 2005 Wiley-Liss, Inc.)

Purpose: To determine the crystal structure of the neotame anhydrate polymorph G and to evaluate X-ray powder diffractometry (XRPD) with molecular modeling as an alternative method for determining the crystal structure of this conformationally flexible dipeptide., Methods: The crystal structure of polymorph G was determined by single crystal X-ray crystallography (SCXRD) and also from the X-ray powder diffraction (XRPD) pattern using molecular modeling (Cerius2, Powder Solve module)., Results: From SCXRD, polymorph G crystals are orthorhombic with space group of P2(1)2(1)2(1) with Z = 4, unit cell constants: a = 5.5999(4), b = 11.8921(8), c = 30.917(2) A, and one neotame molecule per asymmetric unit. The XRPD pattern of polymorph G, analyzed by Cerius2 software, led to the same P2(1)2(1)2(1) space group and almost identical unit cell dimensions. However, with 13 rigid bodies defined, Cerius2 gives a conformation of the neotame molecule, which is different from that determined by SCXRD., Conclusions: For neotame anhydrate polymorph G, the unit cell dimensions calculated from XRPD were almost identical to those determined by SCXRD. However, the crystal structure determined by XRPD closely resembled that determined by SCXRD, only when the correct conformation of the neotame molecule had been chosen before detailed analysis of the XRPD pattern.

The conformational flexibility and the molecular packing patterns of the neotame molecule in its various crystal forms, including neotame monohydrate, methanol solvate, ethanol solvate, benzene solvate, and anhydrate polymorph G, are analyzed in this work. The Cerius2 molecular modeling program with the Dreiding 2.21 force field was employed to calculate the most stable conformations of neotame molecules in the gaseous state and to analyze the conformations of the neotame molecule in its various crystal forms. Using graph set analysis, the hydrogen bond patterns of these crystal forms were compared. The neotame molecule takes different conformations in its crystal forms and in the free gaseous state. Cerius2 found 10 conformers with lower conformational energies than those in the actual crystal structures, which represent an energetic compromise. The relatively large differences between the energies of the conformers indicate the necessity for rewriting or customizing the force field for neotame. The hydrogen bonding patterns of the neotame methanol and ethanol solvates are identical, but different from those of the other three forms, which also differ from each other. The neotame molecule in its various crystal forms takes different conformations that differ from those in the gaseous state because of the influence of crystal packing. The intramolecular ring, S5, is present in all the crystal forms. The following hydrogen bonding patterns occur in some of the crystal forms: diad, D; intramolecular rings, S(6) and S(7); chains, C(5) and C(6); and an intermolecular ring, R2(2)(12)., (Copyright 2002 Wiley-Liss, Inc.)

Purpose: To study the relative thermodynamic and kinetic stabilities of neotame anhydrate polymorphs A, D, F, and G, and to develop a quantitative method for analyzing polymorphic mixtures of A and G by powder X-ray diffractometry (PXRD)., Methods: Based on the melting points, heats of fusion, and densities of the four polymorphs, thermodynamic rules were applied to study their thermodynamic relationships. The phase transition temperature of Forms A and G was estimated from their heats of solution and intrinsic dissolution rates (J) in 2-propanol. Using PXRD, a method for the quantitative analysis of polymorphic mixtures of Forms A and G was developed. Binary polymorphic mixtures of Forms A, D, F, or G were stored under zero relative humidity at 23 or 70 degrees C, and their compositions were monitored by PXRD., Results: The endothermic enthalpy of solution of A, D, F, and G follows the rank order: G (29.71 +/- 0.82 kJ/mol, n = 4) > A (28.48 +/- 0.51 kJ/mol, n = 4) > D (20.43 +/- 0.45 kJ/mol, n = 4) > F (18.77 +/- 0.31 kJ/mol, n = 4). The van't Hoff plots of ln(J) against 1/T for A and G show good linearity between 25 degrees C and 32 degrees C. At 23 degrees C polymorphic mixtures remain unchanged for 4 months. However, at 70 degrees C the phase transition is fast and the relative stability of the four polymorphs follows the rank order: G > D > F and G > A., Conclusions: PXRD provides a reliable and accurate technique for the quantitative analysis of polymorphic mixtures of Forms A and G. Among the four polymorphs, A-G and A-D are enantiotropic pairs, whereas D-F, D-G, F-G are monotropic pairs. The phase transition temperature between A and G lies within the range 35-70 degrees C.

The dehydration of neotame monohydrate was monitored at various temperatures by differential scanning calorimetry (DSC), thermogravimetry (TGA), hot-stage microscopy (HSM), powder X-ray diffractometry (PXRD), and (13)C solid-state nuclear magnetic resonance (SSNMR) spectroscopy. This work emphasizes kinetic analysis of isothermal TGA data by fitting to various solid-state reaction models and by model-free kinetic treatment. The dehydration of neotame monohydrate follows the kinetics of a two-dimensional phase boundary reaction (R2) at 40-50 degrees C with an activation energy of 75 +/- 9 kJ/mol, agreeing well with 60-80 kJ/mol from model-free kinetics. At a low heating rate in DSC and TGA, neotame monohydrate undergoes dehydration to produce anhydrate Form E, which then converts to anhydrate Form A, followed by the melting of A. Neotame monohydrate under dry nitrogen purge at 50 mL/min undergoes partial isothermal dehydration at 50 degrees C to produce neotame anhydrate Form A. When neotame monohydrate is heated very slowly from 50 to 65-70 degrees C over 24 h, pure Form A is obtained., (Copyright 2002 Wiley-Liss, Inc.)

Purpose: To prepare, characterize, and compare polymorphs of neotame anhydrate., Methods: Neotame anhydrate polymorphs were prepared from amorphous or crystalline anhydrate by crystallization or suspension in various organic solvents, or by dehydration of neotame monohydrate. The following techniques were used for characterization: differential scanning calorimetry, thermogravimetry, hot-stage microscopy, powder X-ray diffractometry (PXRD), 13C solid-state nuclear magnetic resonance (SSNMR) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy, dynamic water vapor sorption/desorption, and density measurements., Results: Seven polymorphs (Forms A-G) of neotame anhydrate were prepared and show different thermal properties and PXRD patterns. Two enantiotropically related pairs were identified: B and C; E and A. 13C SSNMR and FTIR spectroscopy clearly distinguish between Forms A, D, F, and G, which show similar needle-shaped morphology but distinct differences in dynamic water vapor sorption/desorption and density. The 13C SSNMR chemical shifts suggest conformational polymorphism. The stability in the presence of water vapor follows the rank order, G > A > D approximately = F, which resembles the rank orders of the molar volume and of the polarity of the solvents from which they crystallized., Conclusions: The neotame anhydrate polymorphs appear to show different molecular conformations. The less dense polymorphic structures crystallize from solvents of greater polarity and sorb water vapor less rapidly and less completely. Two enantiotropic pairs were discerned.

It is possible, using hydrophobic organic acids (such as cinnamate) or hydroxyamino acids (such as serine and tyrosine), to modify the temporal profile of the high-potency sweetener neotame. On the basis of Monte Carlo simulations, it was concluded that it is unlikely that this effect is due to direct interaction between the neotame molecule and the taste modifier. It is shown, using conformational analysis and molecular modeling, that the taste modifiers can adopt low-energy conformers which mimic the proposed active conformation of neotame, which suggests that the modifiers may compete for binding at the receptor site.

We carried out extensive conformational analysis of three high-potency sweeteners: neotame, superaspartame, and SC-45647. We then identified six possible pharmacophore features (carboxylate, two hydrophobic groups, and three NH groups) and wrote a computer program to exhaustively compare intramolecular distances among all possible sets of five-point pharmacophores (carboxylate + two hydrophobic groups + two NH groups) for the three compounds. The best pharmacophore model superimposes low-energy conformers of the three compounds in such a way that the five pharmacophore points match well both sterically and with respect to orientation of hydrogen bond donors and acceptors.