Chlorogenic Acid Enriched Green Coffee Ameliorated Renal Injury in Rats.

The incidence of acute kidney injury (AKI) during the treatment with gentamicin (GM) is very common in hospitalized patients. Green coffee bean, containing chlorogenic acid (CGA) has been reported to improve non communicable diseases. In the present study, CGA enriched fraction of green coffee bean was evaluated on GM induced nephrotoxicity in rats. It was a preclinical case-controlled experimental intervention conducted in the Department of Pharmacology, R G Kar Medical College, Kolkata, India from 2016-2019 using animal model. CGA content of green coffee bean extract (GCBE) was isolated and quantified by high performance thin layer chromatography (HPTLC) (6.426%). The rats were treated with GCBE at the dose of 100, 200 and 400mg/kg in gentamicin (GM) induced AKI for five consecutive days. At day 6, the renal function was assessed through analysing urine, blood and renal tissues. GCBE dose dependently and significantly (p<0.001) lowered blood urea, creatinine and potassium while, enhanced sodium compared to AKI control. Moreover, it showed significant elevation in glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) and reduction in lipid peroxides (p<0.001). It was suggested that chlorogenic acid of green coffee seed can protect kidney through down regulation of p53 transcription factor and thereby attenuation of oxidative stress, inflammation and apoptotic process in renal tubules.

Site-specific modification of Escherichia coli DNA polymerase I large fragment with pyridoxal 5'-phosphate.

Pyridoxal 5'-phosphate (PLP) is an inhibitor of DNA polymerase activity of Escherichia coli DNA polymerase I large fragment. Kinetic studies indicated that overall PLP inhibition was noncompetitive with respect to dNTP, and Hill plot analysis revealed that two molecules of PLP were involved in the inhibition. Reduction of the PLP-treated enzyme with sodium [3H]borohydride resulted in covalent incorporation of 3 mol of PLP/mol of enzyme. This incorporation was at lysine residues exclusively, and the PLP-modified enzyme was not capable of DNA polymerase activity. The presence of dNTP during the modification reaction blocked the incorporation of 1 mol of PLP/mol of enzyme. Similar results were obtained in the presence or absence of template-primer. These data indicate that a PLP target lysine is in or around a dNTP binding site that is essential for polymerase activity and that this binding site is functional in the absence of template-primer. The enzyme modified in the presence of dNTP, containing 2 mol of PLP/mol of enzyme, was capable of DNA polymerase activity but was unable to conduct elongation of product molecules beyond a short oligonucleotide length.

Protein determination with trinitrobenzene sulfonate: a method relatively independent of amino acid composition.

Conditions are described for precise quantitative measurement of microgram protein samples by spectrophotometric determination of the trinitrobenzene derivatives of amino acids in hydrolysates. The mean molar absorbances of individual amino acids were measured and the effective molar absorbance for use in protein measurements of 1.9 X 10(4) A M-1 cm-1 has been determined. From measurements using the trinitrobenzene sulfonate and fluorescamine reagents, and the published data on the o-phthaldialdehyde method, the molar absorption coefficients and the relative fluorescent yields are compared for the amino acids derivatives found in protein hydrolysates. The coefficients of variation for the trinitrobenzene derivatives are less than that for either the fluorescamine or the o-phthaldialdehyde derivatives. The color yields for five soluble proteins were also compared using the Lowry, Bradford, and trinitrobenzene sulfonate reagents. The results show that the described trinitrobenzene sulfonate method is more sensitive and produces a threefold smaller variation in absorbance per milligram protein than either the Lowry or the Bradford methods.