Natural products from plants targeting key enzymes for the future development of antidiabetic agents

Covering: 2000 to January 2023Diabetes is a metabolic disease of serious concern nowadays, with a negative economic impact. In 2021, the International Diabetes Federation estimated that more than 537 million adults live with diabetes, causing over 6.7 million deaths in that year. Intensive scientific research on medicinal plants in the last 100 years reveals that herbal drugs have been an essential source of products for developing antidiabetic agents acting on different physiological targets. This review summarizes recent research from 2000 to 2022 on plant natural compounds affecting selected crucial enzymes (dipeptidyl peptidase IV, diacylglycerol acyltransferase, fructose 1,6-biphosphatase, glucokinase, and fructokinase) involved in glucose homeostasis. Enzyme-aimed treatments usually induce reversible inhibition, irreversible by covalent changes of the objective enzymes, or bind non-covalently but so tightly that their inhibition is irreversible. Depending on the binding site, these inhibitors could be orthosteric or allosteric; in any case, the desired pharmacological action is achieved. One crucial advantage of targeting enzymes in drug discovery is that the required assays are usually simple, using biochemical experiments capable of analyzing enzyme activity.

Impact of comorbidities on hospital mortality in patients with acute pancreatitis: a population-based study of 110,021 patients

BACKGROUND

The impact of pre-existing comorbidities on acute pancreatitis (AP) mortality is not clearly defined. Our study aims to determine the trend in AP hospital mortality and the role of comorbidities as a predictor of hospital mortality.

METHODS

We analyzed patients aged ≥ 18 years hospitalized with AP diagnosis between 2016 and 2019. The data have been extracted from the Spanish National Hospital Discharge Database of the Spanish Ministry of Health. We performed a univariate and multivariable analysis of the association of age, sex, and comorbidities with hospital mortality in patients with AP. The role of the Charlson and Elixhauser comorbidity indices as predictors of mortality was evaluated.

RESULTS

A total of 110,021 patients diagnosed with AP were hospitalized during the analyzed period. Hospital mortality was 3.8%, with a progressive decrease observed in the years evaluated. In multivariable analysis, age ≥ 65 years (OR: 4.11, p < 0.001), heart disease (OR: 1.73, p < 0.001), renal disease (OR: 1.99, p < 0.001), moderate-severe liver disease (OR: 2.86, p < 0.001), peripheral vascular disease (OR: 1.43, p < 0.001), and cerebrovascular disease (OR: 1.63, p < 0.001) were independent risk factors for mortality. The Charlson > 1.5 (OR: 2.03, p < 0.001) and Elixhauser > 1.5 (OR: 2.71, p < 0.001) comorbidity indices were also independently associated with mortality, and ROC curve analysis showed that they are useful for predicting hospital mortality.

CONCLUSIONS

Advanced age, heart disease, renal disease, moderate-severe liver disease, peripheral vascular disease, and cerebrovascular disease before admission were independently associated with hospital mortality. The Charlson and Elixhauser comorbidity indices are useful for predicting hospital mortality in AP patients.

The role of high serum triglyceride levels on pancreatic necrosis development and related complications

BACKGROUND

The relevance of elevated serum triglyceride (TG) levels in the early stages of acute pancreatitis (AP) not induced by hypertriglyceridemia (HTG) remains unclear. Our study aims to determine the role of elevated serum TG levels at admission in developing pancreatic necrosis.

METHODS

We analyzed the clinical data collected prospectively from patients with AP. According to TG levels measured in the first 24 h after admission, we stratified patients into four groups: Normal TG (< 150 mg/dL), Borderline-high TG (150-199 mg/dL), High TG (200-499 mg/dL) and Very high TG (≥ 500 mg/dL). We analyzed the association of TG levels and other risk factors with the development of pancreatic necrosis.

RESULTS

A total of 211 patients were included. In the Normal TG group: 122, in Borderline-high TG group: 38, in High TG group: 44, and in Very high TG group: 7. Pancreatic necrosis developed in 29.5% of the patients in the Normal TG group, 26.3% in the Borderline-high TG group, 52.3% in the High TG group, and 85.7% in the Very high TG group. The trend analysis observed a significant association between higher TG levels and pancreatic necrosis (p = 0.001). A multivariable analysis using logistic regression showed that elevated TG levels ≥ 200 mg/dL (High TG and Very high TG groups) were independently associated with pancreatic necrosis (OR: 3.27, 95% CI - 6.27, p < 0.001).

CONCLUSIONS

An elevated TG level at admission ≥ 200 mg/dl is independently associated with the development of pancreatic necrosis. The incidence of pancreatic necrosis increases proportionally with the severity of HTG.

The role of procalcitonin as a prognostic factor for acute cholangitis and infections in acute pancreatitis: a prospective cohort study from a European single center

BACKGROUND

Infection in acute pancreatitis will worsen the disease prognosis. The aim of our study was to analyze the role of procalcitonin as a prognostic biomarker for infections and clinical severity.

METHOD

A prospective single-cohort observational study of patients diagnosed of acute pancreatitis (n = 152) was designed. PCT determination was tested on admission (first 72 h). Infections (biliary, extrapancreatic and infected pancreatic necrosis), need for antibiotics, urgent ERCP and severity scores for acute pancreatitis was assessed. ROC curves were designed and the area under the curve was calculated. Logistic regression for multivariate analysis was performed to evaluate the association between procalcitonin optimal cut-off level and major complications.

RESULTS

PCT >0.68 mg/dL had higher incidence of global infection, acute cholangitis, bacteraemia, infected pancreatic necrosis, use of antibiotics in general, and need for urgent ERCP. In the multivariate regressions analysis, PCT >0.68 mg/dL at admission demonstrated to be a strong risk factor for complications in acute pancreatitis.

DISCUSSION

PCT levels can be used as a reliable laboratory test to predict infections and the clinical severity of acute pancreatitis. High levels of PCT predict antibiotics prescription as well as the need for urgent ERCP in patients with concomitant clinically severe cholangitis.

Anxiety in MINOCA patients according to latest definitions

Background

Anxiety is a global public health problem affecting the lives of large numbers of patients (pts) and their families. Some studies suggest that pts with MINOCA (myocardial infarction with non-obstructive coronary arteries) have more anxiety levels than the rest of pts with myocardial infarction (MI). The aim of this study is to compare anxiety levels between pts with MINOCA and the rest of MI pts using a validated scale: The State Trait Anxiety Inventory (STAI).

Methods

An analytical and observational study was developed in a University Hospital. We analysed the clinical data of all consecutive MI pts admitted to our centre from July 2017 to December 2020. Inclusion criteria were determined by the 4th Universal Definition of Myocardial Infarction and the latest definitions of MINOCA according to the 2020 ESC Guidelines. A group of experts reviewed all MINOCA cases in order to exclude those who did not fulfil the selection standards and takotsubo syndrome and myocarditis pts were excluded.

STAI questionnaire was completed by each patient during admission. Data collected included “trait anxiety”, that refers to relatively stable individual differences in anxiety-proneness, whereas “state anxiety” is a temporary emotion due to a particular situation (hospitalization in this case). Total score in each subgroup ranges from 0 to 60 points, where a higher score correlates with major anxiety levels.

Follow up analysis included major adverse cardiovascular events (MACE: cardiovascular readmission, myocardial reinfarction, stroke and death from any cause). Survival analysis is based on Cox regression. Median follow-up was 25±23 months.

Results

From a total of 413 consecutive MI pts, 243 (58.8%) completed the questionnaire. Of them, 32 (13%) were MINOCA pts. There were no significant differences in trait anxiety between both groups (MINOCA mean value 21±14 points vs rest of MI 19±10 points, p=0.9), nor in state anxiety (20±14 vs 19±10 points, p=0.8). There were also no significant differences when data were analysed by percentiles: 37.5% of MINOCA pts were below P25 and 28% of the rest of MI were also in this percentile. At the other end of the scale, 31.3% of MINOCA pts were above P75, as well as 22.7% of the rest of MI pts (table 1). During follow up, punctuation in trait anxiety in MINOCA pts showed no differences in MACE (HR 1.01, CI 95% (0.9–1.07)), nor did punctuation in state anxiety (HR 1.01, CI 95% (0.9–1.06)). This was also observed in the rest of MI pts: trait anxiety HR 1.01, CI 95% (0.9–1.04) and state anxiety HR 0.9, CI 95% (0.9–1.01).

Conclusion

In this study, there were no significant differences in anxiety levels between MINOCA pts and the rest of MI pts. The lack of takotsubo pts in this study reflect real data from MINOCA according to the latest definitions. Subjective emotions could lead to mistaken findings, making it necessary to determine emotional disorders with validated and objective tools.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): European Society of Cardiology Table 1. Percentile values of STAI.

Insomnia incidence in myocardial infarction with and without obstructive coronary arteries

Background

Insomnia can either be a primary problem or it may be associated with other psychological conditions, ranging from anxiety to depression. Some studies have reported that pts with MINOCA (myocardial infarction with non-obstructive coronary arteries) have more emotional disorders than the rest of pts with myocardial infarction (MI). However, a relationship with insomnia has not been yet described.

The aim of this study is to compare insomnia levels between patients with MINOCA and the rest of MI patients using a validated scale: Insomnia Severity Index (ISI) (Figure 1).

Methods

We performed an analytical and observational study in which all consecutive MI pts from July 2017 to December 2020 were recruited. We used the latest definitions of MINOCA according to the 2020 ESC Guidelines. A group of experts reviewed all MINOCA cases in order to exclude those who did not fulfil criteria. Therefore, takotsubo syndrome and pts with myocarditis were excluded.

ISI questionnaire was completed by each patient during admission. Total score ranges from 0 to 28 points. Depending on the final score, pts could have no clinically significant insomnia (0–7 points), subthreshold insomnia (8–14 points), clinical insomnia of moderate severity (15–21 points) and severe clinical insomnia (22–28 points).

Follow up analysis included major adverse cardiovascular events (MACE: cardiovascular readmission, myocardial reinfarction, stroke and death from any cause). Survival analysis is based on Cox regression. Median follow-up was 25±23 months.

Results

From a total of 413 consecutive MI pts, 244 (59%) completed the questionnaire. Of them, 32 (13%) were MINOCA pts. There were no statistically significant differences in insomnia levels between both groups (Table 1). Even in absolute terms, both groups presented same mean levels: MINOCA mean value 7.6±6 points vs rest of MI 7.7±6 points, p=0.8. When separated by sex, women in the MI group had higher punctuation levels than men (24% of moderate clinical insomnia in women vs 8.9% of men, p=0.03). Punctuation in ISI questionnaire showed no significant differences in MACE in MINOCA pts (HR 0.9, CI 95% (0.7–1.2)), nor in the rest of MI pts (HR 0.9, CI 95% (0.9–1.03)).

Conclusions

Levels of insomnia were similar in MINOCA pts than in the rest of MI pts. Follow up showed no differences in MACE between both groups regarding insomnia according to ISI. Women had higher punctuation levels than men, with more clinical insomnia in a moderate grade. Subjective emotions could lead to mistaken findings, making it necessary to use ISI questionnaire or other objective validated scales to correctly study some disorders and their distribution in different populations.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Spanish Society of Cardiology Table 1. Insomnia severity indexFigure 1. ISI Questionnaire

Evaluation of the modified computed tomography severity index (MCTSI) and computed tomography severity index (CTSI) in predicting severity and clinical outcomes in acute pancreatitis

OBJECTIVE

Our main purpose was to compare the modified computed tomography severity index (MCTSI), computed tomography severity index (CTSI), and acute physiological and chronic health evaluation (APACHE)-II predictions regarding severity according to the revised Atlanta classification 2012 and local complications in acute pancreatitis in a consecutive prospective cohort.

METHODS

One hundred and forty-nine patients diagnosed with acute pancreatitis were prospectively enrolled. APACHE-II, MCTSI, and CTSI were calculated for all cases. Severity parameters included persistent organ or multiorgan failure, length of hospitalization, the need for intensive care, death, and local complications (intervention against necrosis and infected necrosis). Area under the receiver operating characteristic curve (AUROC) was calculated and the value of scoring systems was compared.

RESULTS

Both CTSI and MCTSI were associated significantly with all the evaluated severity parameters and showed a correlation between imaging severity and the worst clinical outcomes. Persistent organ failure, persistent multiorgan failure, and death were found in 30 (20.1%), 20 (13.4%), and 13 (8.7%) patients, respectively. The most common extrapancreatic finding was pleural effusion in 76 (51.0%) patients. The AUROC for CTSI was higher for predicting persistent organ failure (0.749, 95% confidence interval [CI] 0.640-0.857), death (AUROC 0.793, 95% CI 0.650-0.936), intervention against necrosis (AUROC 0.862, 95% CI 0.779-0.945), and infected necrosis (AUROC 0.883, 95% CI 0.882-0.930).

CONCLUSIONS

CT indexes outperformed the classic APACHE-II score for evaluating severity parameters in acute pancreatitis, with a slight advantage of CTSI over MCTSI. CTSI accurately predicted pancreatic infections and the need for intervention.

Antidiabeticin vitroandin vivoevaluation of cyclodipeptides isolated fromPseudomonas fluorescensIB-MR-66e

Cyclodipeptides cyclo(l-Pro-l-Leu),1; cyclo(l-Pro-l-Val),2; and cyclo (l-Pro-l-Phe),3fromPseudomonas fluorescensIB-MR-66e showed α-glucosidase inhibitory activity.

End-of-life decisions in emergency patients: prevalence, outcome and physician effect

BACKGROUND

End-of-life decisions (EOLD) represent potentially highly consequential decisions often made in acute situations, such as 'do not attempt resuscitation' (DNAR) choices at emergency presentation.

AIM

We investigated DNAR decisions in an emergency department (ED) to assess prevalence, associated patient characteristics, potential medical and economic consequences and estimate contributions of patients and physicians to DNAR decisions.

DESIGN

Single-centre retrospective observation, including ED patients with subsequent hospitalization between 2012 and 2016. Primary outcome was a DNAR decision and associated patient characteristics. Secondary outcomes were mortality, admission to intensive care unit and use of resources.

METHODS

Associations between DNAR and patient characteristics were analysed using logistic mixed effects models, results were reported as odds ratios (OR). Median odds ratios (MOR) were used to estimate patient and physician contributions to variability in DNAR.

RESULTS

Patients of 10 458 were attended by 315 physicians. DNAR was the choice in 23.3% of patients. Patients' characteristics highly associated with DNAR were age (OR = 4.0, 95% CI = 3.6-4.3) and non-trauma presentation (OR = 2.3, 95% CI = 1.9-2.9). In-hospital mortality was significantly higher (OR = 5.4, CI = 4.0-7.3), and use of resources was significantly lower (OR = 0.7, CI = 0.6-0.8) in patients choosing DNAR. There was a significant effect on DNAR by both patient (MOR = 1.8) and physician (MOR = 2.0).

CONCLUSIONS

DNAR choices are common in emergency patients and closely associated with age and non-trauma presentation. Mortality was significantly higher, and use of resources significantly lower in DNAR patients. Evidence of a physician effect raises questions about the choice autonomy of emergency patients in the process of EOLD.

Interference of l,2,3,4-Tetramethoxy-5-(2-propenyl)benzene with Photosynthetic Electron Transport

The effect of 1,2,3,4-tetramethoxy-5-(2-propenyl)benzene, the major phytogrowth-inhibitory agent isolated from the leaves, stem bark and wood of Malmea depressa (Annonaceae), on several photosynthetic activities has been investigated using freshly lysed spinach chloroplasts. The results indicate that this compound inhibits proton-uptake, ATP synthesis and electron flow (basal, phosphorylating and uncoupled) in a concentration dependent manner, therefore acting as a Hill reaction inhibitor. Uncoupled electron transport through photosystem I from reduced dichlorophenol-indophenol to methylviologen is unaffected by this compound. On the other hand, uncoupled electron transport through photosystem II from water to dichlorophenol-indophenol, from water to silicomolibdate and from diphenylcarbazide to dichlorophenol-indophenol is inhibited by this phenylpropanoid, suggesting that the site of inhibition is located in the span from P680 to QA.

Phenological and geographical influence in the concentration of selected bioactive 4-phenylcoumarins and chlorogenic acid in Hintonia latiflora leaves

ETHNOPHARMACOLOGICAL RELEVANCE

Hintonia latiflora is a Mexican medicinal plant with well-documented ethnomedical record comprising more than 400 years; in modern Mexico is used for treating several maladies such as diabetes and gastric ulcers. Although the pharmacological actions of the stem-bark and leaves have been demonstrated, the phenological and geographical effect on the concentration of active principles remains unexplored.

AIM OF THE STUDY

The main goals of this study were to analyze the amount of selected 4-phenylcoumarins and chlorogenic acid in the leaves in order to assess the best harvesting period, and consequently their pharmacological efficacy. In addition, the preclinical antidiabetic efficacy of the infusion of the leaves was corroborated using standard pharmacological tests.

MATERIALS AND METHODS

The aqueous extracts from the leaves of Hintonia latiflora were prepared by infusion. For phenological and geographical comparison, leaves of Hintonia latiflora were collected in two different regions in Chihuahua and Michoacán. The material was analyzed by UPLC applying an analytical method that developed and validated for this purpose following the ICH guidelines. Investigation of the antidiabetic action was accomplished using an acute hypoglycemic test and oral glucose and sucrose tolerance tests.

RESULTS

The validated analytical method was successfully applied for quantifying chlorogenic acid (1) and 4-phenylcoumarins (2-5) in the leaves of 12 different batches (1-12) during one-year period, and seven different batches for each geographical region; the concentration of the metabolites at the phenological cycle was significantly different, their concentration increased during the pre-senescence phase whereas in the leaf renovation stage the highest concentration of 2-5 was reached. The overall analysis of the active compounds concentration between the two populations investigated seems to be less important than the phenological variations. The aqueous extract of the leaves of Hintonia latiflora exerted its antidiabetic effect by different mechanisms showing comparable effect to the organic extract.

CONCLUSIONS

The findings of the present investigation reveal that the best harvest season for the leaves of Hintonia latiflora is between the leaves renovation and senescence stages avoiding the flowering period. In addition, no significant differences were found among the two different geographical populations analyzed. The infusions of the leaves, rich in 4-phenylcoumarins and chlorogenic acid, showed comparable antidiabetic action than the organic extract.

The structural properties of GaN/AlN core-shell nanocolumn heterostructures

The growth and structural properties of GaN/AlN core-shell nanowire heterostructures have been studied using a combination of resonant x-ray diffraction, Raman spectroscopy and high resolution transmission electron microscopy experiments. For a GaN core of 20 nm diameter on average surrounded by a homogeneous AlN shell, the built-in strain in GaN is found to agree with theoretical calculations performed using a valence force field model. It is then concluded that for an AlN thickness up to at least 12 nm both core and shell are in elastic equilibrium. However, in the case of an inhomogeneous growth of the AlN shell caused by the presence of steps on the sides of the GaN core, plastic relaxation is found to occur. Consistent with the presence of dislocations at the GaN/AlN interface, it is proposed that this plastic relaxation, especially efficient for AlN shell thickness above 3 nm, is promoted by the shear strain induced by the AlN inhomogeneity.

The structural properties of GaN insertions in GaN/AlN nanocolumn heterostructures

The strain state of 1 and 2.5 nm thick GaN insertions in GaN/AlN nanocolumn heterostructures has been studied by means of a combination of high resolution transmission electron microscopy, Raman spectroscopy and theoretical modeling. It is found that 2.5 nm thick GaN insertions are partially relaxed, which has been attributed to the presence of dislocations in the external AlN capping layer, in close relationship with the morphology of GaN insertions and with the AlN capping mechanism. The observed plastic relaxation in AlN is consistent with the small critical thickness expected for GaN/AlN radial heterostructures.

Very low prevalence and no clinical significance of occult hepatitis B in a cohort of HIV-infected patients with isolated anti-HBc seropositivity: the BHOI study

PURPOSE

Data on occult HBV infection in HIV patients are conflicting. We aimed to analyse the prevalence and clinical significance of occult hepatitis B in HIV-infected subjects.

METHOD

An open-label, cross-sectional, multicentre study including all subjects with isolated anti-HBc seropositivity from a cohort of 3,030 HIV-infected patients was undertaken. HBsAg and HBsAb were both negative in all cases, and those patients with acute or convalescent hepatitis B were excluded. HBV DNA was quantified by PCR with a detection limit of 20 IU/mL.

RESULTS

We found 5 cases (2.5%) of occult hepatitis B among 202 HIV-patients with isolated anti-HBc. The mean HBV DNA was 66 (15-112) IU/mL, none had symptomatic hepatitis, and their features, including aminotransferase levels, were similar to those without occult HBV infection.

CONCLUSIONS

Occult hepatitis due to HBV is very unusual in HIV-positive patients with isolated anti-HBc. The use of standard regimens of HAART including drugs with activity against HBV might underestimate the prevalence of occult HBV infection. These patients had a very low viral load, no identifiable risk factors, and no greater risk of hypertransaminasaemia or the development of symptomatic hepatitis.

[Vascular risk factors in patients with ischaemic stroke. Distribution according to age, sex and stroke subtype]

INTRODUCTION

Cardiovascular diseases are one of the leading health problems in developed countries. This term covers conditions such as coronary vascular disease, cerebrovascular diseases and peripheral vascular disease. Ischaemic cerebrovascular disease accounts for 80% of all cerebrovascular diseases. From a clinical point of view it is interesting to distinguish between modifiable and non-modifiable vascular risk factors.

AIM

To analyse the prevalence of modifiable vascular risk factors and their different combinations in a case-control study on ischaemic cerebrovascular disease in the Spanish population, and also the differences in the distribution of the risk factors according to the type of stroke (TOAST classification), age and sex.

SUBJECTS AND METHODS

The study was conducted on 308 patients with ischaemic stroke who were paired by age (+/- 5 years) and sex, with 307 controls with no prior history of thrombosis. The statistical analysis was performed using the software application SAS v. 9.1.

RESULTS

The results suggest that the risk factors are subject to an adding effect, as well as pointing to the presence of a specific profile of these factors depending on the subtype of stroke that is developed.

CONCLUSION

The addition of cardiovascular risk factors is associated with an increased risk of vascular events. The distribution of the modifiable vascular risk factors differs according to the type of stroke and the patient's sex and age.

JAK2 as a molecular marker in myeloproliferative diseases

The molecular pathogenesis of the myeloproliferative disorders (MPD) is poorly understood, except for chronic myeloid leukemia (CML). Recently, several groups have discovered a novel recurrent unique acquired clonal mutation in a tyrosine-kinase JAK2 in patients with Philadelphia-negative MPD and other myeloid disorders. It consists in a guanine-to-thymine change encoding a valine to phenylalanine at codon 617 (JAK2 V617F). JAK2 and the other members of the Janus kinase family are tyrosine kinases that function as intermediates between membrane receptors and intracellular signalling molecules. The mutation occurs within the enzymatically inactive JH2 pseudo-kinase domain that regulates the active JH1 kinase domain. The JAK2 activation leads to constitutive JAK and STAT (activators of transcription) hyperactivation with induction of growth factor hypersensitivity and cell transformation. Some authors have found a higher risk of vascular thrombosis and higher platelet activation when the mutation is present. Therefore, the JAK2 mutation offers a molecular target for new drugs investigation in a similar way to bcr/abl rearrangement in CML. For all these reasons, several studies related to JAK2 have arisen in the last year. In this report, we will review the literature and discuss its possible clinical and prognostic significance.

Endothelium-independent relaxation of aorta rings by two stilbenoids from the orchids Scaphyglottis livida

Gigantol (1) and 3,7-dihydroxy-2,4-dimethoxyphenanthrene (2) from the orchid Scaphyglottis livida induced a significant concentration-dependent relaxation of the contractions evoked by noradrenaline (NA) in endothelium-intact and denuded rat aorta rings. Incubation with N(G)-nitro-L-arginine methyl ester (L-NAME, 1x10(-5) M) or methylene blue (MB, 1x10(-7) M) significantly reduced the relaxation induced by the stilbenoids 1 and 2. The results suggested that two or more mechanisms are involved in the vasorelaxant effects of both compounds.

Spasmolytic stilbenoids from Maxillaria densa

2,5-dihydroxy-3,4-dimethoxyphenanthrene (1), fimbriol-A (2), nudol (3), gymnopusin (4) and erianthridin (5) isolated from Maxillaria densa provoked a concentration-dependent inhibition of the spontaneous contractions of the rat ileum with potencies comparable to papaverine. In order to establish the mode of action of stilbenoids 1-5, their effect on the contractions induced by different spasmogens (histamine, barium chloride and L-NAME) was investigated. In general, the results suggested that the relaxant activity of the products does not involve a direct nitrergic or antihistaminergic mode of action or an interference with calcium influx into the smooth muscle cells.

Alternation of Antiretroviral Drug Regimens for HIV Infection. Efficacy, Safety and Tolerability at Week 96 of the Swatch Study

Introduction

Alternation of antiretroviral drug regimens has been proposed as a novel treatment strategy for HIV infection. However, some concerns persist regarding antiviral efficacy, adherence, toxicity and resistance evolution in the long term.

Methods

A total of 161 antiretroviral-naive HIV-1-infected patients were randomized to receive stavudine/ didanosine/efavirenz (group A) or zidovudine/lamivudine/ nelfinavir (group B) or to alternate between the two regimens every 3 months starting with regimen A (group C). Antiviral efficacy, adherence, safety and tolerability were analysed every 12 weeks.

Results

After 96 weeks, time to virological failure was significantly delayed in the alternating regimen compared with the standards of care regimens. Virological suppression was seen in 46%, 48% and 58% of patients in groups A, B and C, respectively, in the intention-to-treat analysis and in 75%, 76% and 97% in the on-treatment analysis (A vs C: P=0.014; B vs C: P=0.016; A vs B: P=0.849). At the end of the study, 94% of patients in group A and 92% in groups B and C reported an adherence greater than 95%. Alternating therapy was associated with a similar impact on CD4+ counts in comparison with the standards of care regimens, as well as a lower mitochondrial DNA/nuclear DNA (mtDNA/nDNA) ratio decrease in the mitochondrial substudy performed on 37 patients. The frequency and intensity of adverse events in the alternating group decreased during subsequent cycles.

Discussion

Our results favour the hypothesis that proactive therapy switching may delay the accumulation of resistance mutations. Moreover, the alternating regimen was well tolerated and adherence remained comparably high in all treatment groups. The lower mtDNA/nDNA ratio decrease observed in this group may imply a lower impact on mitochondrial toxicity than in standard regimens.

Phytotoxicity and ultrastructural effects of gymnopusin from the orchid Maxillaria densa on duckweed (Lemna pausicostata) frond and root tissues

Two phenanthrene derivatives, characterized as erianthridin (9,10-dihydro-2,7-dihydroxy-3,4-dimethoxyphenanthrene) and gymnopusin (2,7-dihydroxy-3,4,9-trimethoxyphenanthrene), were isolated from an extract of the orchid Maxillaria densa, using phytotoxicity with amaranth (Amaranthus hypochondriacus) to guide fractionation. Gymnopusin and erianthridin inhibited radicle elongation of A. hypochondriacus seedlings with IC(50) values of 330 and 58.2 microM, respectively. The phytoxicity of the two phenanthrene derivatives was also assessed on duckweed (Lemna pausicostata), and compared with mammalian toxicity estimated in vitro with four mammalian cell lines. On duckweed, both phenanthrene derivatives caused electrolyte leakage, chlorophyll loss and photobleaching. Ultrastructural examination of duckweed frond and root tissues treated with gymnopusin (100 microM) revealed membrane damage to the tonoplast after 12 h of exposure. Effects on membrane integrity followed a time course similar to that of electrolyte leakage. Both phenanthrene derivatives exhibited moderate cytotoxicity to all mammalian cells tested, which precludes their use as a bioherbicide.

Phytotoxic naphthopyranone derivatives from the coprophilous fungus Guanomyces polythrix

Reinvestigation of the fermentation broth and mycelium of the coprophilous fungus Guanomyces polythrix, grown in static conditions, led to the isolation of several phytotoxic compounds, including two new naphthopyranone derivatives, namely (2S, 3R)-5-hydroxy-6,8-dimethoxy-2,3-dimethyl-2,3-dihydro-4H-naphtho[2,3-b]-pyran-4-one and (2S, 3R)-5-hydroxy-6,8,10-trimethoxy-2,3-dimethyl-2,3-dihydro-4H-naphtho[2,3-b]-pyran-4-one. The structures of the new compounds were established by spectral and chiroptical methods. In addition, the structure of 8-hydroxy-6-methyl-9-oxo-9H-xanthene-1-carboxylic acid methyl ester was unambiguously determined by X-ray analysis. The isolates caused significant inhibition of radicle growth of two weed seedlings (Amaranthus hypochondriacus and Echinochloa crusgalli) and interacted with both spinach and bovine brain calmodulins.

Geranins C and D, additional new antiprotozoal A-type proanthocyanidins from Geranium niveum

Two new additional A-type proanthocyanidins have been isolated from Geranium niveum. Their structures were determined by spectroscopic, chemical and chiroptical methods as epi-afzelechin-(4beta-->8,2beta-->O-->7)-gallocatechin (1) and epi-afzelechin-(4beta-->8,2beta-->O-->7)-afzelechin-(4beta-->8,2beta-->O-->7)-afzelechin (2). Proanthocyanidins 1 and 2 were given the trivial names of geranins C and D, respectively. Compound 2 showed moderate antiprotozoal activity against Entamoeba histolytica and Giardia lamblia, whereas 1 exhibited weak activity toward E. histolytica.

Biological and mechanistic activities of xanthorrizol and 4-(1',5'-dimethylhex-4'-enyl)-2-methylphenol isolated from Iostephane heterophylla

Xanthorrizol (1) and 4-(1',5'-dimethylhex-4'-enyl)-2-methylphenol (2) were identified as the principal antimicrobial components of a CH(2)Cl(2)-MeOH (1:1) extract derived from Iostephane heterophylla. Compound 2 is a new natural product, but has been synthesized. Both compounds exhibited low level activity (MICs of 16-32 microg/mL) against methicillin-resistant staphylococci and vancomycin-resistant enterococci. They were either inactive or poorly active against Gram-negative bacteria and yeast. Mechanistic studies performed in Escherichia coli imp suggested nonspecific inhibition of DNA, RNA, and protein synthesis by both of these compounds. Compound 1 was tested in an in vivo model; it did not provide protection to mice infected with Staphylococcus aureus.

Antiprotozoal activity of the constituents of Conyza filaginoides

Bioassay-guided fractionation of the antiprotozoal extract of Conyza filaginoides led to the isolation of three new flavonol caffeoyl glycosides, namely, kaempferol 3-O-(6' '-O-E-caffeoyl)-beta-D-galactopyranoside (1), isorhamnetin 3-O-(6' '-O-E-caffeoyl)-beta-D-galactopyranoside (2), and quercetin 3-O-(6' '-O-E-caffeoyl)-beta-D-glucopyranoside (3). In addition, seven known compounds, erythrodiol (4), beta-caryophyllene-4,5-alpha-oxide (5), astragalin (6), isoquercitrin (7), nicotiflorin (8), narcissin (9), and rutin (10), were obtained. The structures of the new isolates were elucidated by spectroscopic and chemical methods. Compounds were also assessed for antiamoebic and antigiardial activities, but none was significantly active compared to the standard drugs evaluated.

Phytotoxic compounds from Xanthocephalum gymnospermoides var. eradiatum

Investigation of the aerial parts of Xanthocephalum gymnospermoides var eradiatum led to the isolation of two new labdane-type of diterpenes, namely, 8 alpha,13S-epoxylabdane-14S,15-diol (1) and methyl grindelate (2). In addition, grindelic acid (3), 7 alpha, 8 alpha-epoxygrindelic acid (4), 7 alpha-hydroxy-8(17)dehydrogrindelic acid (5), 17-hydroxygrindelic acid (6) and 4,5-epoxy-beta-caryophyllene (7) were obtained. The isolated compounds were characterized by spectral means. The absolute configuration of compound 1 was established by chemical correlation with 8 alpha,13S-epoxy-15-nor-labdan-14-oic acid methyl ester of known absolute stereochemistry and by using the advanced Mosher's ester methodology. The results of the present investigation indicated that the known compound barbatol (8) could be an enantiomer of compound 1. Compounds 1-3 and 7 caused significant inhibition of the radicle growth of seedlings of Amaranthus hypochondriacus.

Effect of lichen metabolites on thylakoid electron transport and photophosphorylation in isolated spinach chloroplasts

Investigation of the lichen Parmotrema tinctorum led to the isolation of several known compounds. Among them, lecanorin (1), methyl-beta-orcinol carboxylate, methyl orsellinate, orcinol, and methyl haematommate (3) caused significant inhibition of the radicle growth and germination of seedlings of Amaranthus hypochondriacus and Echinochloa crusgalli. In addition, lecanorin (1) and gyrophoric acid (2) significantly inhibited the light-dependent synthesis of ATP and uncoupled electron transfer on the reducing side of photosystem II in freshly lysed, illuminated spinach chloroplasts. The targets of 1 and 2 were located at the water-splitting enzyme level and in one of the redox enzymes in the range of electron transport from P(680) to Q(A), respectively.

Bioactive compounds from Celaenodendron mexicanum

Bioactivity-directed fractionation of the CHCl3-MeOH extract of the leaves of Celaenodendron mexicanum by means of the brine shrimp lethality test and chromatographic techniques led to the isolation of three carboxylic acid triterpenes, the new tirucalla-type triterpene, 3 alpha-hydroxytirucalla-7,24Z-dien-26-oic acid, 3-oxotirucalla-7,24Z-dien-26-oic acid, and epi-oleanolic acid, and three biflavonoids amentoflavone, podocarpusflavone A, and podocarpusflavone B. Four non-active compounds friedelin, maytensifolin B, 3 beta-hydroxyfriedelan-16-one, and celaenodendrolide were also obtained. epi-Oleanolic acid was the most active against brine shrimps with LC50 value of 23.3 microM. In addition, all isolates were tested for in vitro antiprotozoal and cytotoxic activities. 3-Oxotirucalla-7,24Z-dien-26-oic acid and epi-oleanolic acid showed the highest activity against Leishmania donovani promastigotes with IC50 values of 13.7 and 18.8 microM, respectively. Only 3-oxotirucalla-7,24Z-dien-26-oic acid showed activity against Trypanosoma brucei brucei bloodstream forms with IC50 value of 16.8 microM.

Phytotoxic compounds from the new coprophilous fungus guanomyces polythrix

Bioactivity-directed fractionation of the fermentation broth and mycelium of the coprophilous fungus Guanomyces polythrix led to the isolation of several phytotoxic compounds, including five new naphthopyranone derivatives (1-5). In addition, rubrofusarin B, emodin, citrinin, and 4-hydroxybenzoic acid methyl ester were obtained. The structures of the new compounds were established by spectral and chiroptical methods. The isolates caused significant inhibition of radicle growth of two weed seedlings (Amaranthus hypochondriacus and Echinochloa crusgalli) and interacted with both spinach and bovine brain calmodulins.

New phenylethanoids from Buddleja cordata subsp. cordata

Bioassay-guided fractionation of a crude extract of the stem bark of Buddleja cordata subsp. cordata with significant antimycobacterial activity led to the isolation of a mixture composed by ten new long-chain esters of 2[4'-hydroxyphenyl]-ethanol (1-10), along with the lichen metabolites methyl beta-orcinolcarboxylate (11) and beta-orcinolcarboxylate (12). Extensive HPLC allowed the separation of the major components of the mixture, which were characterized by spectral means as 2[4'-hydroxyphenyl]-ethyl stearate (3), 2[4'-hydroxyphenyl]-ethyl behenate (6), and 2[4'-hydroxyphenyl]-ethyl lignocerate (8). The minor esters were identified as 2[4'-hydroxyphenyl]-ethyl palmitate (1), 2[4'-hydroxyphenyl]-ethyl heptadecanoate (2), 2[4'-hydroxyphenyl]-ethyl nonadecanoate (4), 2[4'-hydroxyphenyl]-ethyl arachidate (5), 2[4'-hydroxyphenyl]-ethyl tricosanoate (7), 2[4'-hydroxyphenyl]-ethyl pentacosanoate (9), and 2[4'-hydroxyphenyl]-ethyl hexacosanoate (10) by GC-MS analysis of the methyl esters derivatives of the fatty acids obtained by alkaline hydrolysis of the mixture. Compound 8 exhibited moderate antibacterial activity against Mycobacterium tuberculosis (MIC = 64 micrograms/ml).

New phenanthrene derivatives from maxillaria densa(1)

Two new phenanthrene derivatives, 2,5-dihydroxy-3, 4-dimethoxyphenanthrene (1) and 9,10-dihydro-2,5-dihydroxy-3, 4-dimethoxyphenanthrene (2), were isolated from an extract prepared from the whole plant of the orchid Maxillaria densa with spasmolytic activity. In addition, four known compounds, namely 2,7-dihydroxy-3, 4-dimethoxyphenanthrene, 9,10-dihydro-2,7-dihydroxy-3, 4-dimethoxyphenanthrene (3), 2,5-dihydroxy-3,4, 9-trimethoxyphe-nanthrene, and 2,7-dihydroxy-3,4, 9-trimethoxyphenanthrene, were obtained. The structures of the isolated compounds were elucidated by spectroscopic methods. In the case of phenanthrene derivatives 1 and 3, the structures were unambiguously assigned by X-ray analysis.

Tryptamine derived amides and acetogenins from the seeds of Rollinia mucosa

Bioactivity-directed fractionation of a CHCl(3)-MeOH (1:1) extract prepared from the seeds of Rollinia mucosa led to the isolation of a mixture of eight novel tryptamine amides. Extensive HPLC allowed the isolation of the major component of the mixture, which was characterized as N-lignoceroyltryptamine (6) using a combination of spectroscopic and chemical methods. The minor amides were identified by GC-MS analysis as N-palmitoyltryptamine (1), N-stearoyltryptamine (2), N-arachidoyltryptamine (3), N-behenoyltryptamine (4), N-tricosanoyltryptamine (5), N-pentacosanoyltryptamine (7), and N-cerotoyltryptamine (8). Two lignans (pinoresinol dimethyl ether and magnolin) and six acetogenins [membranacin (9), desacetyluvaricin (10), rolliniastatin 1, bullatacin, squamocin, and motrilin] were also isolated. The cytotoxicity of membranacin (9) and desacetyluvaricin (10) against six human solid tumor cell lines was determined. The absolute configuration of the former is reported.

A new lanostane-type triterpenoid from Chamaesyce prostrata

A new triterpenoid, namely, lanost-25-en-3-beta-ol, and two known flavonoids (kaempferol-3,6-dimethyl ether and kaempferol 7- O-glucoside) were isolated from the aerial parts of Chamaesyce prostrate (Euphorbiaceae). The structure of the new compound was established based on spectral evidences.

Phytotoxic and photosynthetic activities of maduramicin and maduramicin methyl ester

The polyether antibiotic maduramicin and its methyl ester derivative inhibited photophosphorylation and proton uptake in isolated spinach chloroplasts. Both compounds also enhanced basal and phosphorylating electron transport and stimulated Mg(2+)-dependent ATPase activity, therefore, they behave as uncouplers of photophosphorylation being the methyl ester derivative more potent than the parent compound. On the other hand, maduramicin inhibited germination and radicle elongation of several crop and weed species. In addition, the antibiotic caused phytotoxic injury and fresh weight reduction to 4-to-6 week old seedlings of two weed and two crop species when applied at 10(-4) M by foliar application in the greenhouse.

Geranins A and B, new antiprotozoal A-type proanthocyanidins from Geranium niveum

Bioassay-guided fractionation of the antiprotozoal extract of Geranium niveum led to the isolation of two new A-type proanthocyanidins, epi-afzelechin-(4beta-->8, 2beta-->O-->7)-afzelechin (1) and epi-catechin-(4beta-->8, 2beta-->O-->7)-afzelechin (2). Compounds 1 and 2 were given the trivial names of geranins A and B, respectively. In addition, five known compounds, mahuannin B (3), reynoutrin (4), hyperin (5), methyl gallate (6), and 3-beta-caffeoyl-12-oleanen-28-oic acid (7), were obtained. The structures of the new proanthocyanidins were elucidated by spectroscopic and chemical methods as well as CD measurements. Compounds 1, 2, and 4-7 were tested against axenically grown trophozoites of Giardia lamblia and Entamoeba histolytica.

Effect of selected coumarins on spinach chloroplast photosynthesis

Xanthyletin (1), 3-(1',1'-dimethylallyl)xanthyletin (2), and chalepensin (3), the major coumarins isolated from Stauranthus perforatus, inhibit ATP synthesis from water to methylviologen in spinach thylakoids in a concentration-dependent manner. At low concentration chalepensin (3) inhibits basal and phosphorylating electron flow from water to K(3)[Fe(CN)(6)] without affecting uncoupled electron flow but accelerating Mg(2+)-ATPase activity. Thus, at low concentration the compound behaves as an energy transfer inhibitor. However, at higher concentrations this coumarin acts as an uncoupler because it enhances basal and phosphorylating electron transfer. On the other hand, coumarins 1 and 2 act as Hill reaction inhibitors, although 2 exhibited also uncoupler properties because it induces stimulation of basal and phosphorylating electron flow from water to ferricyanide. The site of interference of xanthyletin was located at the b(6)f-PC level of the electron transport chain.

Nitric oxide/cGMP mediates the spasmolytic action of 3,4'-dihydroxy-5,5'-dimethoxybibenzyl from Scaphyglottis livida

Five aromatic compounds, 3,4'-dihydroxy-5,5'-dimethoxybibenzyl (1), batatasin III (2), coelonin (3), 3,7-dihydroxy-2,4-dimethoxyphenanthrene (4), and 3,7-dihydroxy-2,4,8-trimethoxyphenanthrene (5) were isolated from the orchid Scaphyglottis livida (Lindley) Schltr. Compounds 1-5 induced a concentration-dependent inhibition of the spontaneous contractions of the rat ileum with potencies comparable or higher to that of papaverine. The relaxation evoked by compounds 1-4 was blocked by L-NAME, an inhibitor of nitric oxide synthase. It was also demonstrated that 1 increased cyclic GMP content in rat ileum rings. Compound 1-induced elevation of cGMP was inhibited by L-NAME and ODQ, inhibitors of nitric oxide synthase and soluble guanylyl cyclase, respectively. These results indicate that nitric oxide/cGMP formation constitute the signaling pathway in the spasmolytic action of compound 1.

Purpuracenin: a new cytotoxic adjacent bis-tetrahydrofuran annonaceous acetogenin from the seeds of Annona purpurea

Purpuracenin, a novel cytotoxic acetogenin and annaglaucin, a known compound, were isolated from the seeds of Annona purpurea. Their structures were elucidated by a combination of chemical and spectral methods including MS and NMR spectral measurements. The absolute configurations of both compounds are presented. The new compound and annoglaucin exhibited potent cytotoxic activity in vitro against six human solid tumor cell lines.

Purpurediolin and purpurenin, two new cytotoxic adjacent bis-tetrahydrofuran annonaceous acetogenins from the seeds of Annona purpurea

Two novel cytotoxic acetogenins, purpurediolin (1) and purpurenin (2), were isolated from the seeds of Annona purpurea. Their structures were elucidated by a combination of chemical and spectral methods including MS and NMR measurements. In addition, six known acetogenins were obtained, namely, bullatacin, squamocin (annonin I), motrilin (squamocin C), annoglaucin, xylomatenin, and annonacin A. Compounds 1 and 2 exhibited potent cytotoxic activity in vitro against six human solid tumor cell lines.

[Invasive maxilar sinusitis by Rhizopus oryzae]

We herein present a diabetic with non Hodgkin lymphoma patient that had been treated with steroids and developed fungal invasive sinusitis. The patient had intensive facial pain that did not respond to antibiotics and on clinical inspection had a necrotic lesion on right nasal area. A smear and biopsy tissue showed broad non septate hyphae and on cultures Rhizopus oryzae was isolated. There was an unfavorable outcome, and the patient died even though liposomal Amphotericin B was administered and surgical treatment was performed.

Smooth muscle relaxing flavonoids and terpenoids from Conyza filaginoides

Activity-guided fractionation of the smooth muscle relaxing, chloroform-methanol (1:1) extract of Conyza filaginoides (D.C.) Hieron (Asteraceae) led to the isolation of three flavonoids (quercetin 3-glucoside, rutin, and pinostrobin), one sterol (alpha-spinasterol), a sesquiterpenoid (beta-caryophyllene 4,5-alpha-oxide), and two triterpenoids (erythrodiol and 3-beta-tridecanoyloxy-28-hydroxyolean-12-ene). 3-beta-Tridecanoyloxy-28-hydroxy-olean-12-ene is a new naturally occurring terpenoid. All the isolated compounds induced a concentration-dependent inhibition of the spontaneous contractions of rat ileum. The spasmolytic activity exhibited by the extract and active principles tends to support the traditional use of C filaginoides as an antispasmodic agent.