In Vivo Biochemical and Gene Expression Analyses of the Antioxidant Activities and Hypocholesterolaemic Properties of Tamarindus indica Fruit Pulp Extract

Background

Tamarindus indica (T. indica) is a medicinal plant with many biological activities including anti-diabetic, hypolipidaemic and anti-bacterial activities. A recent study demonstrated the hypolipidaemic effect of T. indica fruit pulp in hamsters. However, the biochemical and molecular mechanisms responsible for these effects have not been fully elucidated. Hence, the aims of this study were to evaluate the antioxidant activities and potential hypocholesterolaemic properties of T. indica, using in vitro and in vivo approaches.

Methodology/Principal Findings

The in vitro study demonstrated that T. indica fruit pulp had significant amount of phenolic (244.9±10.1 mg GAE/extract) and flavonoid (93.9±2.6 mg RE/g extract) content and possessed antioxidant activities. In the in vivo study, hamsters fed with high-cholesterol diet for ten weeks showed elevated serum triglyceride, total cholesterol, HDL-C and LDL-C levels. Administration of T. indica fruit pulp to hypercholesterolaemic hamsters significantly lowered serum triglyceride, total cholesterol and LDL-C levels but had no effect on the HDL-C level. The lipid-lowering effect was accompanied with significant increase in the expression of Apo A1, Abcg5 and LDL receptor genes and significant decrease in the expression of HMG-CoA reductase and Mtp genes. Administration of T. indica fruit pulp to hypercholesterolaemic hamsters also protected against oxidative damage by increasing hepatic antioxidant enzymes, antioxidant activities and preventing hepatic lipid peroxidation.

Conclusion/Significance

It is postulated that tamarind fruit pulp exerts its hypocholesterolaemic effect by increasing cholesterol efflux, enhancing LDL-C uptake and clearance, suppressing triglyceride accumulation and inhibiting cholesterol biosynthesis. T. indica fruit pulp has potential antioxidative effects and is potentially protective against diet-induced hypercholesterolaemia.     

Microarray analysis revealed different gene expression patterns in HepG2 cells treated with low and high concentrations of the extracts of Anacardium occidentale shoots

In this study, the effects of low and high concentrations of the Anacardium occidentale shoot extracts on gene expression in liver HepG2 cells were investigated. From MTT assays, the concentration of the shoot extracts that maintained 50% cell viability (IC₅₀) was 1.7 mg/ml. Cell viability was kept above 90% at both 0.4 mg/ml and 0.6 mg/ml of the extracts. The three concentrations were subsequently used for the gene expression analysis using Affymetrix Human Genome 1.0 S.T arrays. The microarray data were validated using real-time qRT–PCR. A total of 246, 696 and 4503 genes were significantly regulated (P < 0.01) by at least 1.5-fold in response to 0.4, 0.6 and 1.7 mg/ml of the extracts, respectively. Mutually regulated genes in response to the three concentrations included CDKN3, LOC100289612, DHFR, VRK1, CDC6, AURKB and GABRE. Genes like CYP24A1, BRCA1, AURKA, CDC2, CDK2, CDK4 and INSR were significantly regulated at 0.6 mg/ml and 1.7 mg but not at 0.4 mg/ml. However, the expression of genes including LGR5, IGFBP3, RB1, IDE, LDLR, MTTP, APOB, MTIX, SOD2 and SOD3 were exclusively regulated at the IC₅₀ concentration. In conclusion, low concentrations of the extracts were able to significantly regulate a sizable number of genes. The type of genes that were expressed was highly dependent on the concentration of the extracts used.     

Record of Blue tilapia Oreochromis aureus (Steindachner, 1864) in the Eerste River catchment,Western Cape province,South Africa

Oreochromis aureus was imported from Israel into South Africa in 1959 but data on its current status in South Africa are lacking. Genomic DNA was extracted and the COI gene amplified at the South African Institute for Aquatic Biodiversity. The identity of the sequences and specimens was determined using the Barcode of Life Data Systems and GenBank. Morphological and genetic assessment demonstrated that 11 specimens collected from two farm dams in the Eerste River System, Western Cape province, were Oreochromis aureus. A MaxEnt model compiled using global distribution, rainfall and temperature data predicted that large areas of southern Africa were climatically suitable for this species, indicating considerable invasion debt in southern Africa. As a result, surveys to assess for the extent of the invasion in South Africa and eradication of existing populations, if feasible, are recommended management actions.     

Striped catfish (Pangasianodon hypophthalmus) could be suitable for coastal aquaculture

Salinity intrusion in the coastal freshwater rivers due to climate change and construction of the dam in the upstream rivers are alarming in aquaculture. Hence, an experiment was conducted to know the effects of salinity on growth performance, hemato‐biochemical parameters and erythrocytes structure in a commercially cultivable catfish species, striped catfish (Pangasianodon hypophthalmus). Firstly, median lethal concentration (LC₅₀) of salinity for striped catfish was determined and then the fish were exposed to three salinity conditions (4, 8 and 12‰) and a control (0‰). Fish were sacrificed at day 7, 14, 28 and 56 after the start of salinity exposure. The 96 hr LC₅₀ value was found to be 14.87‰. Salinity levels from freshwater to 8‰ showed optimal conditions with high survival rate and good growth performances of fish in terms of weight gain and specific growth rate (SGR). Interestingly, the lowest food conversion ratio (FCR) was found in 4‰ group. The hemoglobin (Hb) level and number of red blood cells (RBCs) were found to be decreased significantly in 8 and 12‰ compared to 0 and 4‰ at the initial days of exposure, while number of white blood cells (WBCs) and glucose level showed opposite scenario. Frequencies of ENA (erythrocytic nuclear abnormalities) and ECA (erythrocytic cellular abnormalities) were significantly increased with increasing salinities in the initial days of exposure. Overall, findings of the present study revealed that striped catfish might be suitable fish species for culture in the brackish water containing salinity up to 10‰.     

Characterization of photodamage to escherichia coli in optical traps

Optical tweezers (infrared laser-based optical traps) have emerged as a powerful tool in molecular and cell biology. However, their usefulness has been limited, particularly in vivo, by the potential for damage to specimens resulting from the trapping laser. Relatively little is known about the origin of this phenomenon. Here we employed a wavelength-tunable optical trap in which the microscope objective transmission was fully characterized throughout the near infrared, in conjunction with a sensitive, rotating bacterial cell assay. Single cells of Escherichia coli were tethered to a glass coverslip by means of a single flagellum: such cells rotate at rates proportional to their transmembrane proton potential (. J. Mol. Biol. 138:541-561). Monitoring the rotation rates of cells subjected to laser illumination permits a rapid and quantitative measure of their metabolic state. Employing this assay, we characterized photodamage throughout the near-infrared region favored for optical trapping (790-1064 nm). The action spectrum for photodamage exhibits minima at 830 and 970 nm, and maxima at 870 and 930 nm. Damage was reduced to background levels under anaerobic conditions, implicating oxygen in the photodamage pathway. The intensity dependence for photodamage was linear, supporting a single-photon process. These findings may help guide the selection of lasers and experimental protocols best suited for optical trapping work.     

Characterization of AmphiF-spondin reveals the modular evolution of chordate F-spondin genes

The F-spondin genes are a family of extracellular matrix molecules united by two conserved domains, FS1 and FS2, at the amino terminus plus a variable number of thrombospondin repeats at the carboxy terminus. Currently, characterized members include a single gene in Drosophila and multiple genes in vertebrates. The vertebrate genes are expressed in the midline of the developing embryo, primarily in the floor plate of the neural tube. To investigate the evolution of chordate F-spondin genes, I have used the basal position in chordate phylogeny of the acraniate amphioxus. A single F-spondin-related gene, named AmphiF-spondin, was isolated from amphioxus. Based on molecular phylogenetics, AmphiF-spondin is closely related to a particular subgroup of vertebrate F-spondin genes that encode six thrombospondin repeats. However, unlike these genes, expression of AmphiF-spondin is not confined to the midline but is found through most of the central nervous system. Additionally, AmphiF-spondin has lost three thrombospondin repeats and gained two fibronectin type III repeats, one of which has strong identity to a fibronectin type III repeat from Deleted in Colorectal Cancer (DCC). Taken together, these results suggest a complex evolutionary history for chordate F-spondin genes that includes (1) domain loss, (2) domain gain by tandem duplication and divergence of existing domains, and (3) gain of heterologous domains by exon shuffling.