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Vestenbergsgreuth, Germany

Da-Costa-Rocha I.,University of London | Bonnlaender B.,Plantextrakt GmbH and Co. KG | Sievers H.,PhytoLab GmbH and Co. KG. | Pischel I.,University of London | And 2 more authors.
Food Chemistry | Year: 2014

Hibiscus sabdariffa L. (Hs, roselle; Malvaceae) has been used traditionally as a food, in herbal drinks, in hot and cold beverages, as a flavouring agent in the food industry and as a herbal medicine. In vitro and in vivo studies as well as some clinical trials provide some evidence mostly for phytochemically poorly characterised Hs extracts. Extracts showed antibacterial, anti-oxidant, nephro- and hepato-protective, renal/diuretic effect, effects on lipid metabolism (anti-cholesterol), anti-diabetic and anti-hypertensive effects among others. This might be linked to strong antioxidant activities, inhibition of α-glucosidase and α-amylase, inhibition of angiotensin-converting enzymes (ACE), and direct vaso-relaxant effect or calcium channel modulation. Phenolic acids (esp. protocatechuic acid), organic acid (hydroxycitric acid and hibiscus acid) and anthocyanins (delphinidin-3-sambubioside and cyanidin-3-sambubioside) are likely to contribute to the reported effects. More well designed controlled clinical trials are needed which use phytochemically characterised preparations. Hs has an excellent safety and tolerability record. © 2014 The Authors. Published by Elsevier Ltd. Source


Bohner M.,University of Hohenheim | Bohner M.,Plantextrakt GmbH and Co. KG | Barfuss I.,University of Hohenheim | Heindl A.,University of Hohenheim | Muller J.,University of Hohenheim
Biosystems Engineering | Year: 2013

The problem of uneven drying over the belt width in belt dryers is a consequence of inadequate air distribution leading to decreased throughput and high energy requirements. To achieve system optimisation, computational fluid flow simulations were conducted. A problem was discovered in the air distribution to both sides of the dryer, due to the incorrect angle of an adjustable distribution flap. When the angle was adjusted to 45°, the air mass flows from both sides were equal. Furthermore the air distribution across the belt width was inhomogeneous, studied by measurements of the air temperature and product moisture distribution. The simulation of the airflow led to the addition of air guiding plates. The influence of the guiding plates adjoining the drying chamber was confirmed by the fluid path length of the hot air. The study resulted in an optimised airflow over the drying area and uniform product moisture content. © 2013 IAgrE. Source


Netzel G.,Friedrich - Schiller University of Jena | Kammerer D.R.,University of Hohenheim | Carle R.,University of Hohenheim | Kler A.,Plantextrakt GmbH and Co. KG | And 4 more authors.
Journal of the Science of Food and Agriculture | Year: 2012

Background: To evaluate health benefits attributed to Hibiscus sabdariffa L. a randomized, open-label, two-way crossover study was undertaken to compare the impact of an aqueous H. sabdariffa L. extract (HSE) on the systemic antioxidant potential (AOP; assayed by ferric reducing antioxidant power (FRAP)) with a reference treatment (water) in eight healthy volunteers. The biokinetic variables were the areas under the curve (AUC) of plasma FRAP, ascorbic acid and urate that are above the pre-dose concentration, and the amounts excreted into urine within 24 h (Ae 0-24) of antioxidants as assayed by FRAP, ascorbic acid, uric acid, malondialdehyde (biomarker for oxidative stress), and hippuric acid (metabolite and potential biomarker for total polyphenol intake). Results: HSE caused significantly higher plasma AUC of FRAP, an increase in Ae 0-24 of FRAP, ascorbic acid and hippuric acid, whereas malondialdehyde excretion was reduced. Furthermore, the main hibiscus anthocyanins as well as one glucuronide conjugate could be quantified in the volunteers' urine (0.02% of the administered dose). Conclusion: The aqueous HSE investigated in this study enhanced the systemic AOP and reduced the oxidative stress in humans. Furthermore, the increased urinary hippuric acid excretion after HSE consumption indicates a high biotransformation of the ingested HSE polyphenols, most likely caused by the colonic microbiota. © 2012 Society of Chemical Industry. Source


Fitzenberger E.,Justus Liebig University | Deusing D.J.,Justus Liebig University | Wittkop A.,Justus Liebig University | Kler A.,Plantextrakt GmbH and Co. KG | And 3 more authors.
Plant Foods for Human Nutrition | Year: 2014

Enhanced blood glucose levels are a hallmark of diabetes and are associated with diabetic complications and a reduction of lifespan. In order to search for plant extracts that display preventive activities in such a scenario, we tested 16 extracts used in human nutrition for their survival enhancing activities in the nematode Caenorhabditis elegans. Nematodes were exposed for 48 h to 10 mM glucose in the absence or presence of 0.1 % extract. Thereafter, survival was measured at 37 °C. Extracts made from coffee, kola, rooibos and cinnamon, did not influence the glucose-induced reduction of survival. Those made from ginseng, camomile, lime blossom, paraguay tea, balm, rhodiola, black tea, or knotgrass all extended the lifespan of the glucose-treated nematodes significantly but did not rescue survival completely. Extracts from the leaves of blackberries, from hibiscus, elderberries, or jiaogulan completely countered the glucose-induced survival reduction. A potent activation of the proteasome was shown for the most preventive extracts suggesting a more efficient degradation of proteins impaired by glucose. In conclusion, we present a simple animal model to screen for plant extracts with potency to reverse glucose toxicity. Extracts from blackberry leaves, hibiscus, elderberries, and jiaogulan were identified as very potent in this regard whose exact mechanisms of action appear worthwile to investigate at the molecular level. © 2014 Springer Science+Business Media New York. Source


Deusing D.J.,Justus Liebig University | Winter S.,Justus Liebig University | Kler A.,Plantextrakt GmbH and Co. KG | Kriesl E.,Plantextrakt GmbH and Co. KG | And 3 more authors.
Fitoterapia | Year: 2015

Hyperglycemia is a hallmark of diabetes mellitus which leads to the onset of complications in the long term. Green tea through its high content of polyphenolic catechins, on the other hand, is suggested to prevent or at least delay such detrimental complications. In the present study we fed the nematode Caenorhabditis elegans on a liquid medium supplemented with 10 mM glucose in the absence or presence of a catechin-enriched green tea extract (CEGTE). After exposure of young adults for 48 h survival was subsequently measured under heat stress at 37 °C. Whereas CEGTE at 0.01% did not affect the survival of wild type nematodes, it completely reversed the glucose-induced survival reduction. Those effects were not achieved through the monomeric catechins included in CEGTE. RNA interference (RNAi) for sir-2.1 not only prevented the survival extension by CEGTE under simultaneous glucose exposure but also caused a further reduction of survival. Likewise, the knockdown of uba-1, encoding the only E1-ubiquitin-activating enzyme in C. elegans, proved that UBA-1 is essential for the survival extension by CEGTE and that its loss of function changes CEGTE from a survival extending into a survival reducing extract. Stimulation of the proteasome by CEGTE was finally proven through measurements of the proteolytic cleavage of a fluorogenic peptide substrate. To conclude, our studies provide evidence that CEGTE reverses glucose-induced damage in C. elegans through activation of adaptive responses mediated by SIR-2.1 and proteasomal degradation. The hormetic mode of action is revealed by a reduction of survival once the adaptive processes were blocked. © 2015 Elsevier B.V. All rights reserved. Source

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