Effect of Rooibos and Honeybush Tea Extracts Against Botrytis cinerea

Green tea extracts from the indigenous South African rooibos (Aspalathus linearis) and honeybush (Cyclopia species)plants were evaluated as potential antifungal agents against the plant pathogen Botrytis cinerea. When applied at 10mg/ml, the tea extracts stimulated biomass production in B. cinerea by more than 3-fold after 24 hrs. This inductioncould not be linked directly to the presence of selected micro- and macronutrients or antioxidants in the extracts,suggesting a complex set of yet unidentified factors that may act synergistically to enhance cell growth. However,when applied at 100 mg/ml, the A. linearis and C. genistoides extracts reduced spore germination of B. cinerea by33.3% and 16.7%, respectively. This suggests that the tea extracts contain active compounds that should be furtherinvestigated for their potential as natural anti-fungal agents

The synergistic and neuroprotective effects of alcohol–antioxidant treatment on blood–brain barrier endothelial cells

Background: Alcohol (EtOH) is reported to adversely affect one of the most crucial roles of the blood–brain barrier (BBB), the regulation of its permeability, thereby compromising the stability of the homeostatic environment of the brain. The central component of the BBB, endothelial cells (ECs), regulates BBB transcellular transport, while their paracellular pathways are made virtually impermeable by molecular structures called tight junctions (TJs). These TJs are composed of proteins, such as claudin-5, a protein involved in the regulation of paracellular permeability and of key interest in this study. Methods and Results: The working hypothesis of this study postulated that the high levels of antioxidants (AOs) in the fermented Aspalathus linearis (Rooibos; Rf) tincture may protect the ECs of the BBB against oxidative stress induced by EtOH exposure. Cells were exposed for 24 hours to selected concentrations of EtOH (25 and 100 mM), Rf (containing an antioxidant equivalence of 1.9 nM Aspalathin), and cotreatments of EtOH and Rf. Cell viability, live cell number, and toxicity were analyzed using the trypan blue exclusion assay. RT-qPCR was implemented to quantify claudin-5 transcription. In addition, permeability (Transepithelial Electrical Resistance) of bEnd5 monolayers was measured. The experimental timeline for the above-mentioned parameters was 24 and 48 hours. Conclusions: Our study showed that simultaneous exposure of Rf and EtOH was able to negate the effects of EtOH on cell viability and cell proliferation, but was not able to reverse or reduce the effects of EtOH on claudin-5 transcription and paracellular permeability. Furthermore, a novel finding in this study suggests that very low concentrations of AOs in tinctures such as Rooibos tea could profoundly alter the redox status of brain ECs

Die uitwerking van molekulêre swaeldioksied op die groei, asyn- en glukoonsuur produksie van geselekteerde Suid-Afrikaanse asynsuur bakteriële gisrasse.

Please help us populate SUNScholar with the post print version of this article. It can be e-mailed to: [email protected] En Wynkund

Die uitwerking van molekulêre swaeldioksied op die groei, asyn- en glukoonsuur produksie van geselekteerde Suid-Afrikaanse asynsuur bakteriële gisrasse.

Please help us populate SUNScholar with the post print version of this article. It can be e-mailed to: [email protected] En Wynkund

Effect of rooibos and honeybush tea extracts against Botrytis cinerea

The original publication is available at http://www.sasev.org/.Green tea extracts from the indigenous South African rooibos (Aspalathus linearis) and honeybush (Cyclopia species) plants were evaluated as potential antifungal agents against the plant pathogen Botrytis cinerea. When applied at 10 mg/ml, the tea extracts stimulated biomass production in B. cinerea by more than 3-fold after 24 hrs. This induction could not be linked directly to the presence of selected micro- and macronutrients or antioxidants in the extracts, suggesting a complex set of yet unidentified factors that may act synergistically to enhance cell growth. However, when applied at 100 mg/ml, the A. linearis and C. genistoides extracts reduced spore germination of B. cinerea by 33.3% and 16.7%, respectively. This suggests that the tea extracts contain active compounds that should be further investigated for their potential as natural anti-fungal agents.Publishers' versio

Enhancement of Rooibos (Aspalathus linearis) aqueous extract and antioxidant yield with fungal enzymes

The leaves and stems of the Rooibos plant (Aspalathus linearis) are used for the production of an herbal tea known for its health promoting properties, which have been linked to its flavonoid content but which is substantially reduced by the traditional processing method employed. Selected foodgrade fungi were screened for their potential to improve the yield of soluble matter extracted from rooibos plant material. Fungal cocktails of hydrolyzing enzymes enhanced either the yield of soluble solids (Lentinula edodes and Rhizopus oryzae cultured in yeast peptone-wheat straw medium) or the yield in antioxidants from fermented rooibos (R oryzae cultured in potato dextrose or yeast peptone-wheat straw medium). When applied to green rooibos, L. edodes (cultured in yeast peptone-wheat straw medium) enhanced the release of soluble solids as well as color formation, leading to semifermented rooibos with a relatively high aspalathin content, compared to fermented rooibos. © 2008 American Chemical Society.Articl