Acute and sub-chronic toxicity studies of methanolic extract of Tulbaghia violacea rhizomes in Wistar rats

The methanolic extract of the rhizome of Tulbaghia violacea (RTV) was tested for toxicity in albino Wistar rats. A single oral administration of a 5 g/kg dosage of RTV extract did not produce mortality or significant behavioral changes during 14 days of observation. In the sub-chronic study, the extract administered daily for a period of 28 days showed no mortality or morbidity and the relative weights of organs were not affected by the treatment. However, significant weight gain in both treated and control group was observed. Indicators of liver damage such as alanine amino transferase (ALT) and aspartate amino transferase (AST), as well as total serum protein and albumin showed no significant alteration in the extract treated animals when compared with the controls at all doses used. The extracts caused a significant (p<0.05) decrease in the activity of gamma glutamy transferase (ƔGT) and alkaline phosphatase (ALP) when compared with the control. However, the extract did not have any significant effect on markers of kidney function or hematological parameters in the rats, except in the female rats where a significant increase (p<0.05) in lymphocytes counts at 500 mg/kg was observed. Histopathological examination of the liver revealed no detectable inflammation. These results suggest that the rhizomes of T. violacea may be potentially safe for consumption.Keywords: Tulbaghia violacea, rhizomes, acute toxicity, subchronic toxicit

Chemical composition profiling and antifungal activity of the essential oil and plant extracts of Mesembryanthemum edule (L.) bolus leaves

Background: Essential oil from Mesembryanthemum edule leaves have been used by the Eastern Cape traditional healers for the treatment ofrespiratory tract infections, tuberculosis, dysentery, diabetic mellitus, laryngitis and vaginal infections. The investigation of bioactive compoundsin the essential oil of this plant could help to verify the efficacy of the plant in the management or treatment of these illnesses.Materials and methods: Various concentrations of the hydro-distilled essential oil, ranging from 0.005-5 mg/ml, were tested against some fungal strains, using the micro-dilution method. Minimum inhibitory activity was compared with four other different crude extracts of hexane, acetone,ethanol and aqueous samples from the same plant. The chemical composition of the essential oil, hexane, acetone and ethanol extracts wasdetermined using GC-MS.Result: GC/MS analysis of the essential oil resulted in the identification of 28 compounds, representing 99.99% of the total oil. Phytoconstituentsof hexane, acetone and ethanol extracts yielded a total peak chromatogram of fifty nine compounds. A total amount of 10.6% and 36.61% of the constituents were obtained as monoterpenes and oxygenated monoterpenes. Sesquiterpene hydrocarbons (3.58%) were relatively low compared to the oxygenated sesquiterpenes (9.28%), while the major concentrated diterpenes and oxygenated diterpenes were 1.43% and 19.24 %, respectively and phytol 12.41%. Total amount of fatty acids and their methyl esters content, present in the oil extract, were found to be 19.25 %. Antifungal activity of the oil extract and four solvent extracts were tested against five pathogenic fungal strains. The oil extract showed antifungal activity against Candida albican, Candida krusei, Candida  rugosa, Candida glabrata and Cryptococcus neoformans with MIC ranges of 0.02-0.31 mg/ml. Hexane extract was active against the five fungal strains with MICs ranging between 0.02-1.25 mg/ml. Acetone extracts were active against C. krusei only at 0.04mg/ml. No appreciable antifungal activity was found in either ethanol or water extracts when compared with commercial antibiotics.Conclusion: The profile of chemical constituents found in M. edule essential oil and its antifungal properties support the use of M. edule by traditional healers as well as in the pharmaceutical and food industries as a natural antibiotic and food preservative.Key words: Mesembryanthemum edule, Essential oil, GC/MS, Antifungal activity, Opportunistic fung

Anti-hyperlipidemic and biochemical effect of extract of Tulbaghia violacea rhizomes on high cholesterol diet fed rats

Anti-hyperlipidemic and biochemical effect of methanolic extract of Tulbaghia violacea rhizomes were investigated in cholesterol rich diet induced hypercholesterolemia Wistar albino rats. Hypercholesterolemia was induced in rats by feeding with 2% cholesterol rich diet (high cholesterol diet, HCD) for four weeks. Some biochemical parameters and histology of the liver were assessed following 28 days oral treatment. Co-administration of extract of T. violacea rhizomes at 250 and 500 mg/kg respectively, significantly (p<0.05) protected against hypercholesterolemia induced alanine amino transferase (ALT) alterations in activities of serum aspartate amino transferase (AST), alanine amino transferase (ALT), alkaline phosphatase (ALP), total bilirubin (TB), lactate dehydrogenase (LDH), gamma glutamyl transferase (γGT), total cholesterol, triglycerides, albumin and total protein in a dose dependent manner. The extract also caused significant (p<0.05) increase in high density lipoprotein (HDL) cholesterol level. Anti-cholesterolemic and hepatoprotective effect of the extract at both doses were comparable and similar to that of the standard treatment of atorvastatin (30 mg/kg body weight). Histological examination of the liver showed that the extract markedly protected against hypercholesterolemia induced micro vesicular steatosis. This study suggests that T. violacea rhizome extract may protect against hypercholesterolemic induced diseases and this may account for its folklore usage.Keywords: Anti-hyperlipidemic, Tulbaghia violacea rhizome, biochemical, lipid profil

Geometry and electronic structure of iridium adsorbed on graphene

We report investigation of the geometry and electronic structure of iridium atoms adsorbed onto graphene through a combined experimental and theoretical study. Ir atoms were deposited onto a flake of graphene on a Pt(111) surface and found to form clusters even at low temperatures. The areal density of the observed clusters on the graphene flake suggests the clusters are most likely pairs of Ir atoms. Theoretical ab initio density functional (DFT) calculations indicate that these Ir dimers are oriented horizontally, near neighboring "bridge" sites of the graphene lattice, as this configuration has the strongest adsorption energy of all high-symmetry configurations for the Ir dimer. A large peak in the local density of states (LDOS) at the Dirac point energy was measured via scanning tunneling spectroscopy, and this result is reproduced by a DFT calculation of the LDOS. The peak at the Dirac point energy is found to be from the Ir s and p states. The LDOS in the monomer case was also calculated, and is found to significantly differ from the experimentally determined data, further supporting the hypothesis of low-temperature clustering

Compositions and comparisons of antimicrobial potencies of some essential oils and antibiotics against selected bacteria

The antimicrobial activities of 10 essential oils extracted from various plant species were investigated and compared with the activities of 10 commercial antibiotics against 10 strains of bacteria using agardiffusion method. Although, all the essential oils were active at concentration ranging from 0.5 to 1.5 mg/ml, their activities were more lower than the commercial antibiotics. However, being natural productsthe oils have been reported to be much safer than the antibiotics. Another advantage of the essential oils used in this study was their broad spectrum activities against gram positive and gram negative bacteria. The oils were analyzed by GC and GC-MS techniques in order to determine their activecompounds

The endoplasmic reticulum remains functionally connected by vesicular transport after its fragmentation in cells expressing Z-alpha(1)-antitrypsin

α1-Antitrypsin is a serine protease inhibitor produced in the liver that is responsible for the regulation of pulmonary inflammation. The commonest pathogenic gene mutation yields Z-α1-antitrypsin, which has a propensity to self-associate forming polymers that become trapped in inclusions of endoplasmic reticulum (ER). It is unclear whether these inclusions are connected to the main ER network in Z-α1-antitrypsin-expressing cells. Using live cell imaging, we found that despite inclusions containing an immobile matrix of polymeric α1-antitrypsin, small ER resident proteins can diffuse freely within them. Inclusions have many features to suggest they represent fragmented ER, and some are physically separated from the tubular ER network, yet we observed cargo to be transported between them in a cytosol-dependent fashion that is sensitive to N-ethylmaleimide and dependent on Sar1 and sec22B. We conclude that protein recycling occurs between ER inclusions despite their physical separation.—Dickens, J. A., Ordóñez, A., Chambers, J. E., Beckett, A. J., Patel, V., Malzer, E., Dominicus, C. S., Bradley, J., Peden, A. A., Prior, I. A., Lomas, D. A., Marciniak, S. J. The endoplasmic reticulum remains functionally connected by vesicular transport after its fragmentation in cells expressing Z-α1-antitrypsin

Integrating personality research and animal contest theory: aggressiveness in the green swordtail <i>Xiphophorus helleri</i>

&lt;p&gt;Aggression occurs when individuals compete over limiting resources. While theoretical studies have long placed a strong emphasis on context-specificity of aggression, there is increasing recognition that consistent behavioural differences exist among individuals, and that aggressiveness may be an important component of individual personality. Though empirical studies tend to focus on one aspect or the other, we suggest there is merit in modelling both within-and among-individual variation in agonistic behaviour simultaneously. Here, we demonstrate how this can be achieved using multivariate linear mixed effect models. Using data from repeated mirror trials and dyadic interactions of male green swordtails, &lt;i&gt;Xiphophorus helleri&lt;/i&gt;, we show repeatable components of (co)variation in a suite of agonistic behaviour that is broadly consistent with a major axis of variation in aggressiveness. We also show that observed focal behaviour is dependent on opponent effects, which can themselves be repeatable but were more generally found to be context specific. In particular, our models show that within-individual variation in agonistic behaviour is explained, at least in part, by the relative size of a live opponent as predicted by contest theory. Finally, we suggest several additional applications of the multivariate models demonstrated here. These include testing the recently queried functional equivalence of alternative experimental approaches, (e. g., mirror trials, dyadic interaction tests) for assaying individual aggressiveness.&lt;/p&gt