Cytotoxicity and hepatoprotective attributes of methanolic extract of Rumex vesicarius L.

Background

To evaluate the hepatoprotective potential and invitro cytotoxicity studies of whole plant methanol extract of Rumex vesicarius L. Methanol extract at a dose of 100 mg/kg bw and 200 mg/kg bw were assessed for its hepatoprotective potential against CCl₄-induced hepatotoxicity by monitoring activity levels of SGOT (Serum glutamic oxaloacetic transaminase), SGPT (Serum glutamic pyruvic transaminase), ALP (Alkaline phosphatase), TP (Total protein), TB (Total bilirubin) and SOD (Superoxide dismutase), CAT (Catalase), MDA (Malondialdehyde). The cytotoxicity of the same extract on HepG2 cell lines were also assessed using MTT assay method at the concentration of 62.5, 125, 250, 500 μg/ml.

Results

Pretreatment of animals with whole plant methanol extracts of Rumex vesicarius L. significantly reduced the liver damage and the symptoms of liver injury by restoration of architecture of liver. The biochemical parameters in serum also improved in treated groups compared to the control and standard (silymarin) groups. Histopathological investigation further corroborated these biochemical observations. The cytotoxicity results indicated that the plant extract which were inhibitory to the proliferation of HepG2 cell line with IC50 value of 563.33 ± 0.8 μg/ml were not cytotoxic and appears to be safe.

Conclusions

Rumex vesicarius L. whole plant methanol extract exhibit hepatoprotective activity. However the cytotoxicity in HepG2 is inexplicable and warrants further study.     

Pathways involved in fluid phase and adsorptive endocytosis in neuroblastoma

The endocytosis of ricin, horseradish peroxidase (HRP), and a conjugate of ricin-HRP by monolayer cultures of murine neuroblastoma was studied using morphological and biochemical techniques. The binding of (125)I-ricin and (125)I-ricin-HRP to cells at 4 degrees C, as a function of ligand concentration, was a saturable process. The apparent affinity constants, determined at equilibrium, were 2.8 X 10(6) M(-1) for ricin and 1 x 10(6) M(-1) for ricin-HRP. The number of binding sites per cell was 8 x 10(7) and 3 x 10(7) for the lectin and the conjugate, respectively. The binding of (125)I-ricin to monolayers as not proportional to cell density. We found reduced binding at higher cell concentrations, suggesting a decrease in the accessibility of the ligand for the receptor site or fewer sites with increasing cell population. Neuroblastoma cells have an acid-phosphatase-positive network of cisternae and vesicles near the Golgi apparatus (GERL). Ricin-HRP undergoes endocytosis in vesicles and cisternae corresponding to GERL, and in residual bodies (dense bodies). The cellular uptake of ricin-HRP was 100-200 times greater than free HRP and there was no stimulation of fluid phase endocytosis by ricin. When monolayers were exposed to concentrations of native HRP 100-fold that of the conjugate, cellular uptake of peroxidase was comparable, but HRP was localized only in residual bodies and never in elements of GERL. These results support the conclusion that GERL is involved in the adsorptive endocytosis of ricin-HRP, while residual bodies are involved in the bulk uptake of HRP. In addition, the binding, uptake, and possible recycling of (125)I- subunit B (the binding subunit) of ricin and of (125)I-ricin was examined by quantitative electron microscope autoradiography. Both ricin and its binding subunit displayed similar autoradiographic grain distributions at 4 degrees C, and there was no evidence of their breakdown or recycling to the plasma membrane during endocytosis for 2 h.     

Urinary pathogenicity of Proteus mirabilis strains isolated from faeces or urine

Urinary and faecal isolares of Proteus mirabilis were studied with respect to a number of bacterial properties as possible virulence factors in the pathogenesis of urinary tract infections: experimental virulence in a mouse model, haemolysin production, haemagglutinating properties, hydrophobicity of the bacterial surface, sensitivity to the bactericidal effect of human serum, serotype and cell invasiveness. Urinary isolates were slightly more virulent than faecal isolates in the mouse model. No other significant differences were found between both groups. So urinary strains seem to be selected from the faecal reservoir mainly on the basis of their prevalence in the faeces and not on the basis of the possession of particular virulence factors.     

Physiological and metabolic responses to a hill walk.

The physiological and metabolic demands of hill walking have not been studied systematically in the field despite the potentially deleterious physiological consequences of activity sustained over an entire day. On separate occasions, 13 subjects completed a self-paced hill walk over 12 km, consisting of a range of gradients and terrain typical of a mountainous walk. During the hill walk, continuous measurements of rectal (T(re)) and skin (T(sk)) temperatures and of respiratory gas exchange were made to calculate the total energy expenditure. Blood samples, for the analysis of metabolites and hormones, were taken before breakfast and lunch and immediately after the hill walk. During the first 5 km of the walk (100- to 902-m elevation), T(re) increased (36.9 +/- 0.2 to 38.5 +/- 0.4 degrees C) with a subsequent decrease in mean T(sk) from this time point. T(re) decreased by approximately 1.0 degrees C during a 30-min stop for lunch, and it continued to decrease a further 0.5 degrees C after walking recommenced. The total energy intake from both breakfast and lunch [5.6 +/- 0.7 (SE) MJ] was lower than the energy expended [14.5 +/- 0.5 (SE) MJ; P < 0.001] during the 12-km hill walk. Despite the difference in energy intake and expenditure, blood glucose concentration was maintained. The major source of energy was an enhanced fat oxidation, probably from adipose tissue lipolysis reflected in high plasma nonesterified fatty acid concentrations. The major observations were the varying thermoregulatory responses and the negative energy balance incurred during the hill walk. It is concluded that recreational hill walking can constitute a significant metabolic and thermoregulatory strain on participants.     

Determination of dehydroalanine residues in proteins and peptides: An improved method

Dehydroalanine residues in peptides and proteins react with 4-pyridoethanethiol in alkaline solution to form 4-pyridoethyl cysteine residues, which after acid hydrolysis, give the corresponding amino acid. An experimental protocol has been developed, and with simple dehydroalanine derivatives, conversions of 96–99% are achieved. Tests with peptides and proteins show that serine and cysteine/cystine residues do not interfere with this analytical procedure. A sample of wool keratin contained 57 µmol dehydroalanine/g.     

Thiol solutions--inhibition of autoxidation

A technique is described for maintaining thiol solutions in their reduced form by the addition of tributylphosphine which can subsequently be removed by extracting with sulfur in chloroform.