Helmut Hugel

Microwave multicomponent synthesis.

In the manner that very important research is often performed by multidisciplinary research teams, the applications of multicomponent reactions involving the combination of multiple starting materials with different functional groups leading to the higher efficiency and environmentally friendly construction of multifunctional/complex target molecules is growing in importance. This review will explore the advances and advantages in microwave multicomponent synthesis (MMS) that have been achieved over the last five years.

The effects of Eleutherococcus senticosus and Panax ginseng on steroidal hormone indices of stress and lymphocyte subset numbers in endurance athletes

A clinical trial was undertaken to investigate the effects of Eleutherococcus senticosus (ES) and Panax ginseng (PG) on competitive club-level endurance athletes engaged in their normal in-season training. Participants were matched for training stress and received a 33% ethanolic extract (8 mL/day) containing either ES, PG (equivalent to 4 g and 2 g/day of dried root, respectively), or a placebo. A pre-test and post-test were used to evaluate the effects of six weeks of supplementation on cortisol, testosterone, and testosterone to cortisol ratio (TCR) as well as circulating numbers of total T-cells, T-helper cells (CD4), T-suppressor cells (CD8), CD4 to CD8 ratio, natural killer cells, and B lymphocytes. None of the immune system variables changed significantly nor showed any clear trend from pre to post test in any of the treatment groups. No significant change in testosterone, cortisol or TCR was observed in the PG group. In the ES group, however, TCR decreased by 28.7% from 0.0464 to 0.0331 (P=0.03). The main contribution to this decrease appeared to be a non-significant (P= 0.07) 31% trend towards increased cortisol rather than a very small non-significant (P = 0.36) 7% decrease in the calculated mean for testosterone. This result suggested that contrary to initial expectation, ES increased rather than decreased hormonal indices of stress, which may be consistent with animal research suggesting a threshold of stress below which ES increases the stress response and above which ES decreases the stress response.

Herbal medicine for dementia: A systematic review

This systematic review aimed to assess the effectiveness and safety of herbal medicines (HM) for treating dementia. Databases in English and Chinese were searched from their inceptions to February 2007. References in reviews and randomized controlled trials (RCTs) were screened by hand. Trials comparing orally administered HM with placebo, no intervention or other therapy were considered. Trials on Ginkgo biloba and its extracts were excluded to avoid duplication of existing reviews. Pairs of authors independently applied eligibility criteria, extracted data and assessed methodological quality using the Jadad Scale. Thirteen RCTs met the inclusion criteria of three or above on this scale. Six trials compared herbal medicine with placebo, one with no treatment, and the remainder with pharmaceutical intervention. Meta‐analyses were performed on common cognitive performance outcome measures. All studies reported HM had significant effects in improving symptoms. In studies that employed active controls, HM was at least as effective as the pharmaceutical intervention. Meta‐analyses found HM more effective than no treatment or placebo and at least equivalent to control interventions, although the overall effect was small. No severe adverse events were reported. These trials provide overall positive evidence for the effectiveness and safety of certain HMs for dementia management. Copyright

Polyphenol protection and treatment of hypertension.

INTRODUCTION High blood pressure is the major risk factor for cardiovascular diseases and the rising prevalence of human hypertension precedes the trend toward a global epidemic of unhealthy ageing. A focus on lifestyle and dietary interventions minimizes dependency on pharmacological antihypertensive therapies. REVIEW Observational studies indicate that the intake of dietary flavonoids is associated with a decreased risk of cardiovascular disease (CVD). The evidence suggests that the dietary intakes of polyphenol-rich foods, herbs and beverages including flavonols, anthocyanidins, proanthocyanidins, flavones, flavanones, isoflavones and flavan-3-ols, improves vascular health, thereby significantly reducing the risk of hypertension and CVD. Consumption is associated with an improvement in endothelial function via vascular eNOS and Akt activation. Increased NO bioavailability improves vasodilation and blood circulation, effects protein kinases, ion channels and phosphodiesterases, counteracting vascular inflammation and LDL oxidative stress. Importantly, some polyphenols also inhibit the activity of matrix metalloproteinases, inhibit angiotensin converting enzyme activity and thereby improving SBP and DSB. We review the improvement of polyphenol intake on blood pressure and endothelial function for the treatment of hypertension, including not only observational but also RCTs and pre-clinical studies. CONCLUSION The antihypertensive phytotherapy of polyphenol-rich foods for protection and improving endothelial function with vascular relaxation occurs via the NO-cGMP pathway and ACE inhibition. OPCs stimulate endothelium-dependent vasodilation, suppress vasoconstrictor ET-1 synthesis, activate a laminar shear stress response in endothelial cells and also inhibit the activity of metalloproteinases including ACE lowering blood pressure.

Evaluating the traditional Chinese literature for herbal formulae and individual herbs used for age-related dementia and memory impairment.

Natural products are the basis of many systems of traditional medicine and continue to provide sources for new drugs. Ethnobiological approaches to drug discovery that have proven productive in the past include the investigation of traditional medical literatures. This study describes a broadly applicable method for locating, selecting and evaluating citations in the traditional Chinese herbal medicine literature of the dynastic period (until 1911) for specific symptoms or disorders. This methodology is applied to evaluate multi-herb formulae for age-related dementia and memory impairment. Of the 174 multi-herb formulae located in the searches, 19 were for disorders broadly consistent with amnestic Mild Cognitive Impairment (MCI) and/or Age Associated Memory Impairment (AAMI). These appeared in books written between c. 650 to 1911. Of the 176 herbs that appeared in these 19 formulae, those with the highest frequencies were tabulated and hierarchical cluster analysis was undertaken. Chinese pharmacopoeias were consulted to determine the botanical identity of the herbs and also which herbs within the formulas were specific for memory disorders. This study found that the top ten herbs, in terms of frequency of inclusion in multi-herb formulae specific for age-related memory disorders, were all listed in the pharmacopoeias for memory disorders and these formed three clusters. The herbs identified in this study may warrant further experimental and clinical evaluation both individually and in combination.

Does acupuncture or Chinese herbal medicine have a role in the treatment of allergic rhinitis

Purpose of review Complementary medicines, including acupuncture and Chinese herbal medicine, are being used increasingly for the management of allergies such as allergic rhinitis. Until relatively recently, however, evidence for the efficacy and safety of these therapies in allergic conditions has been lacking. Recent findings A limited number of well conducted studies, all with small sample sizes, have demonstrated the promising therapeutic potential of acupuncture and Chinese herbal medicine for allergic rhinitis. The possible additional benefit of combining the two therapies, however, is yet to be confirmed. There are concerns about the appropriateness of the sham/placebo controls that have been used in acupuncture studies and also about the safety evaluation of individual herbs and herbal formulations. In addition to well established symptom scores and specific quality of life questionnaires, the concurrent use of conventional anti-allergy medications has been utilized as an outcome measure in a number of trials that have evaluated the effectiveness of acupuncture and Chinese herbal medicine for allergic rhinitis. Summary Tentatively, it appears that acupuncture and Chinese herbal medicine can be effective treatments for allergic rhinitis. Confirmatory evidence, however, is needed from large and, ideally, multi-centre trials.

The electrochemical reduction of indigo dissolved in organic solvents and as a solid mechanically attached to a basal plane pyrolytic graphite electrode immersed in aqueous electrolyte solution

The electrochemical properties of solid materials such as organic compounds, irrespective of their electrical conductivity, can be studied via the use of submicron sized particles mechanically attached to electrode surfaces immersed in aqueous media containing different electrolytes. In this study the reduction of solid indigo in buffered and non-buffered aqueous media has been investigated. Data are compared to those obtained from a voltammetric study of indigo dissolved in dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF) and in pyridine and the interpretation of results is facilitated by in situ EPR, in situ UV–VIS spectroscopy and atomic force microscopy (AFM) studies. For the reduction of solid indigo two distinct types of reduction processes, ‘surface-type’ and ‘bulk-type’, have been observed. The latter process has been found to be associated with the reductive dissolution of indigo. The ‘surface-type’ responses which occur in a microphase at the electrode/solid/solution interface are reversible 2H+-2e- reduction and oxidation processes with a corresponding 60 mV shift in half wave potential per pH unit in buffered electrolyte media over the pH range 4 to 11. The ‘bulk-type’ reduction process is proposed to be associated with the electroinsertion of cations into the solid indigo particles, thereby producing a reduced material and causing the loss of material from the electrode surface under convective flow conditions. The electrochemical solubilization of indigo occurred in non-buffered aqueous media even at neutral pH values.

Solid-phase microextraction—On-fibre derivatization with comprehensive two dimensional gas chromatography analysis oftrans-resveratrol in wine

SummaryTrans-resveratrol, found in wine, grapes, peanuts, soy and tea, is one constituent of the polyphenol class which is reported to be beneficial to animal health. The analysis oftrans-resveratrol may be accomplished by use of solid-phase microextraction (SPME), with on-fibre derivatization in order to improve the subsequent GC analysis (to increase the volatility and recovery) of the extracted solute.An 85 μm polyacrylate SPME fibre was selected for this study, and the SPME method incorporated a modification to the procedure to remove moisture and permit the use of water sensitive derivatizing reagents. Both BSTFA and acetic anhydride reagents were tested. Comprehensive two-dimensional gas chromatography (GC×GC) with a cryogenic modulation system was employed for the final chromatographic separation step. It was found that successful separation of resveratrol derivatives from potential interferences, that cause peak overlap in single column GC analysis of complex red wine samples, could be achieved. This increased separation power allows more accurate quantitative results for extractedtrans-resveratrolReproducible positioning of thetrans-resveratrol peak in the 2D separation space was found in the SPME-GC×GC experiment, consistent with other studies on GC×GC retention reproducibility. Calibration curves for peak area were prepared for SPME extracted resveratrol, for both derivatising reagents, and good linearity (R2 ca. 0.998) was achieved.Thetrans-resveratrol content of five Australian red wine samples was determined by using the acetic anhydride derivatizing reagents, and optimum conditions for the analysis were established.

Synthetic studies on the salicylihalamides: macrolactone formation via ring closing metathesis versus macrolactonization

Abstract Two routes to the unusual 12-membered unsaturated benzolactone of the highly cytotoxic marine metabolites the salicylihalamides are presented. The first involves an RCM step to construct the C9C10 alkene bond and this provided the model macrolactones 9 and 10 in a ratio of 77:23, respectively. An alternative route involved a Stille coupling to construct the C8C9 bond followed by a macrolactonization to give the lactones 9 and 10 in a ratio of 96:4.

Simultaneous deconvolution and re-construction of primary and secondary overlapping peak clusters in comprehensive two-dimensional gas chromatography

In this study, simultaneous deconvolution and reconstruction of peak profiles in the first ((1)D) and second dimension ((2)D) of comprehensive two-dimensional (2D) gas chromatography (GC×GC) is achieved on the basis of the property of this new type of instrumental data. First, selective information, where only one component contributes to the peak elution window of a given modulation event, is employed for stepwise stripping of each (2)D peak with the help of pure components corresponding to that compound from the neighbouring modulations. Simulation based on an exponentially modified Gaussian (EMG) model aids this process, where the EMG represents the envelope of all (2)D peaks for that compound. The peak parameters can be restricted by knowledge of the pure modulated (2)D GC peaks derived from the same primary compound, since it is modulated into several fractions during the trapping and re-focusing process of the cryogenic modulation system according to the modulation period. Next, relative areas of all pure (2)D components of that compound are considered for reconstruction of the primary peak. This strategy of exploitation of the additional information provided by the second dimension of separation allows effective deconvolution of GC×GC datasets. Non-linear least squares curve fitting (NLLSCF) allows the resolved 2D chromatograms to be recovered. Accurate acquisition of the pure profiles in both (1)D and (2)D aids quantification of compositions and prediction of 2D retention parameters, which are of interest for qualitative and quantitative analysis. The ratio between the sum of squares of deconvolution residual and original peak response (R(rr)) is employed as an effective index to evaluate the resolution results. In this work, simulated and experimental examples are used to develop and test the proposed approach. Satisfactory performance for these studies is validated by minimum and maximum R(rr) values of 1.34e-7% and 1.09e-2%; and 1.0e-3% and 3.0e-1% for deconvolution of (1)D and (2)D peaks, respectively. Results suggest that the present technique is suitable for GC×GC data processing.