Thaumatin Research Articles

Fruit Extract of Thaumatococcus daniellii Reduces Oxidative Stress in Rats

Thaumatococcus daniellii (Benn.) Benth is a tropical rhizomatous herb recognized as the natural source of the protein sweetner, thaumatin. Thaumatin is extracted from the fruit arils, which constitutes about 4% of the fruit leaving a large chunk as waste in the extraction process. In this study, we examined the effect of ethanolic extract of T. daniellii fruit pulp on some oxidative stress parameters in male Wistar rats. The fruit pulp was extracted with 80% ethanol and a graded concentration was administered orally to the rats for 14 days. The liver and kidney of the rats were harvested; in‐vivo antioxidant activity and liver histopathology were determined. Result were statistically analysed using one way analysis of variance (ANOVA) supplemented with Duncan multiple range test (DMRT). Results showed a significant (p<0.05) decrease in MDA levels and a significant increase (p<0.05) in SOD activity and GSH concentration compared to the normal and positive controls. Histopathological examinations indicated no pathologic abnormality. The antioxidant boosting activities of the T. daniellii fruit extract may be due to the presence of phytochemicals such as flavonoids and tannins. The study suggests the medicinal potential of the fruit in reducing oxidative stress. The fruit could be incorporated into animal feed for its nutritive and phytochemical constituents.

Tailoring orthogonal proteomic routines to understand protein separation during ion exchange chromatography

Surface charge, molecular weight, and folding state are known to influence protein chromatographic behaviour onto ion exchangers. Experimentally, information related to such factors can be gathered via 2-DE methods. The application of 2-D PAGE under denaturing/reducing conditions was already shown to reveal separation trends within a large protein population from cell extracts. However, ion-exchange chromatography normally runs under native conditions. A tailored protocol consisting in a first separation based on IEF on Immobiline strips under native conditions followed by a second dimension SDS-PAGE run was adopted. The chromatographic versus electrophoretic separation behaviours of two model proteins, thaumatin (TAU) and BSA, were compared to better understand which proteomic routine would be better suited to anticipate IEX chromatographic separations. It was observed that the information contained in the pI value obtained with the adapted 2-DE protocol showed better correlation with the IEX chromatographic behaviour. On the other hand, chromatographic separations performed in the presence of urea as a denaturant have demonstrated the potential influence of hydrodynamic radius/conformation on protein separation. Moreover, the information provided by such 2-D system correlated well with the chromatographic behaviour of an additional set of pure proteins. An initial prediction of protein ion-exchange chromatographic behaviour could be possible utilizing an experimental approach based on 2-DE running under milder chemical conditions. This technique provides information that more closely resembles the separation behaviour observed with a complex biotechnological feedstock.

Expression of foreign proteins in microorganisms.

The various alternative strategies for the expression of heterologous proteins in microorganisms are reviewed. To illustrate how these general considerations can be addressed in particular cases, the expression of chimeric human-mouse antibodies in Escherichia coli and the production of thaumatin, an intensely sweet plant protein, in yeast, are described.

The water–sweet aftertaste of neohesperidin dihydrochalcone and thaumatin as a method for determining their sweet persistence

Description et application d'une methode d'evaluation de la persistance de la saveur de substances a saveur sucree intense dans des conditions de pH et de temperatures fixees