Biosynthesis and characterization of silver nanoparticles using ginger spent and their antibacterial activity

Ginger spent is the byproduct of spice industries that remove the essential oils of ginger (Zingiber officinale) for food industry and medicinal purposes. Ginger is a well known spice used often for seasoning in Indian cuisine. The de-oiled ginger has no specific use mostly goes to waste. Hence, we utilized this industrial waste product in the efficient synthesis of silver nanoparticles with the aid of UV irradiation from a solution of 1mM silver nitrate and spent extract in the ratio 9:1. Immediate colour change from pale yellow to dark brown was noted indicating the rapid synthesis of silver nanoparticles. These nanoparticles were centrifuged, dried and well characterized. UV Vis Spectroscopy, XRD analysis, Zeta potential and SEM analysis was carried out. It was commendable that the size of the nanoparticles fell well within the upper limit of 100nm. Agar well diffusion method was used to screen the antimicrobial activity of the well characterized silver nanoparticles. They were tested against seven pathogenic strains of three gram negative bacteria (Escherichia coli, Klebsiella pneumonia and Pseudomonas aeruginosa) three gram positive bacteria(Bacillus subtilis, Staphylococcus aureus and Streptococcus faecalis) and a fungus (Candida  albicans). It was seen that the zone of inhibition(ZOI) in well plate method  increased on increasing the concentration of silver nanoparticles. Further studies could lead to the application of these silver nanoparticles in medicine

Screening of Indigenous Oxalate Degrading Lactic Acid Bacteria from Human Faeces and South Indian Fermented Foods: Assessment of Probiotic Potential

Lactic acid bacteria (LAB) have the potential to degrade intestinal oxalate and this is increasingly being studied as a promising probiotic solution to manage kidney stone disease. In this study, oxalate degrading LAB were isolated from human faeces and south Indian fermented foods, subsequently assessed for potential probiotic property in vitro and in vivo. Based on preliminary characteristics, 251 out of 673 bacterial isolates were identified as LAB. A total of 17 strains were found to degrade oxalate significantly between 40.38% and 62.90% and were subjected to acid and bile tolerance test. Among them, nine strains exhibited considerable tolerance up to pH 3.0 and at 0.3% bile. These were identified as Lactobacillus fermentum and Lactobacillus salivarius using 16S rDNA sequencing. Three strains, Lactobacillus fermentum TY5, Lactobacillus fermentum AB1, and Lactobacillus salivarius AB11, exhibited good adhesion to HT-29 cells and strong antimicrobial activity. They also conferred resistance to kanamycin, rifampicin, and ampicillin, but were sensitive to chloramphenicol and erythromycin. The faecal recovery rate of these strains was observed as 15.16% (TY5), 6.71% (AB1), and 9.3% (AB11) which indicates the colonization ability. In conclusion, three efficient oxalate degrading LAB were identified and their safety assessments suggest that they may serve as good probiotic candidates for preventing hyperoxaluria

Renoprotective effect of tectorigenin glycosides isolated from Iris spuria L. (Zeal) against hyperoxaluria and hyperglycemia in NRK-49Fcells

Oxidative stress has been identified as an underlying factor in the development of insulin resistance, β-cell dysfunction, impaired glucose tolerance and type 2 diabetes mellitus and it also play major role in kidney stone formation. The present study is aimed to elucidate the in vitro nephroprotective activity of two isoflavonoid glycosides, tectorigenin 7-O-β-D-glucosyl-(1→6)-β-D-glucoside (1) and tectorigenin 7-O-β-D-glucosyl-4'-O-β-D-glucoside (2) isolated from the n-BuOH fraction of Iris spuria L. (Zeal) rhizome MeOH extract against oxalate and high glucose-induced oxidative stress in NRK-49F cells. The results revealed that compounds 1 and 2 significantly increased the antioxidant enzyme activities and decreased MDA levels in both oxalate and high glucose stress. Treatment with these phytochemicals effectively down-regulated expression of crystal modulator genes and pro-fibrotic genes in oxalate and high glucose-mediated stress respectively. This study indicates cytoprotective, antioxidant, anti-urolithic and anti-diabetic effects of compounds 1 and 2 against oxalate and high glucose stress

Secretion of Biologically Active Heterologous Oxalate Decarboxylase (OxdC) in Lactobacillus plantarum WCFS1 Using Homologous Signal Peptides

Current treatment options for patients with hyperoxaluria and calcium oxalate stone diseases are limited and do not always lead to sufficient reduction in urinary oxalate excretion. Oxalate degrading bacteria have been suggested for degrading intestinal oxalate for the prevention of calcium oxalate stone. Here, we reported a recombinant Lactobacillus plantarum WCFS1 (L. plantarum) secreting heterologous oxalate decarboxylase (OxdC) that may provide possible therapeutic approach by degrading intestinal oxalate. The results showed secretion and functional expression of OxdC protein in L. plantarum driven by signal peptides Lp_0373 and Lp_3050. Supernatant of the recombinant strain containing pLp_0373sOxdC and pLp_3050sOxdC showed OxdC activity of 0.05 U/mg and 0.02 U/mg protein, while the purified OxdC from the supernatant showed specific activity of 18.3 U/mg and 17.5 U/mg protein, respectively. The concentration of OxdC protein in the supernatant was 8–12 μg/mL. The recombinant strain showed up to 50% oxalate reduction in medium containing 10 mM oxalate. In conclusion, the recombinant L. plantarum harboring pLp_0373sOxdC and pLp_3050sOxdC can express and secrete functional OxdC and degrade oxalate up to 50% and 30%, respectively

Expression of heterologous oxalate decarboxylase in HEK293 cells confers protection against oxalate induced oxidative stress as a therapeutic approach for calcium oxalate stone disease

Oxalates stimulate alterations in renal epithelial cells and thereby induce calcium oxalate (CaOx) stone formation. Bacillus subtilis YvrK gene encodes for oxalate decarboxylase (OxdC) which degrades oxalate to formate and CO2. The present work is aimed to clone the oxdC gene in a mammalian expression vector pcDNA and transfect into Human Embryonic Kidney 293 (HEK293) cells and evaluate the oxdC expression, cell survival rate and oxalate degrading efficiency. The results indicate cell survival rate of HEK293/pcDNAOXDC cells pre-incubated with oxalate was enhanced by 28%. HEK293/pcDNAOXDC cells expressing OxdC treated with oxalate, significantly restored antioxidant activity, mitochondrial membrane potential and intracellular reactive oxygen species (ROS) generation compared with HEK293/pcDNA. Apoptotic marker caspase 3 downregulation illustrates HEK293/pcDNAOXDC cells were able to survive under oxalate-mediated oxidative stress. The findings suggest HEK293 cells expressing oxdC capable of degrading oxalate protect cells from oxidative damage and thus serve as a therapeutic option for prevention of CaOx stone disease

Oral administration of oxalate-enriched spinach extract as an improved methodology for the induction of dietary hyperoxaluric nephrocalcinosis in experimental rats

<p>Experimental induction of hyperoxaluria by ethylene glycol (EG) administration is disapproved as it causes metabolic acidosis while the oral administration of chemically synthesized potassium oxalate (KOx) diet does not mimic our natural system. Since existing models comprise limitations, this study is aimed to develop an improved model for the induction of dietary hyperoxaluria, and nephrocalcinosis in experimental rats by administration of naturally available oxalate rich diet. Male albino Wistar rats were divided into five groups. Group I, control; group II rats received 0.75% EG, group III rats fed with 5% KOx diet and group IV and V rats were administered with spinach extract of 250 and 500 mg soluble oxalate/day respectively, for 28 d. Urine and serum biochemistry were analyzed. After the experimental period, rats were sacrificed, liver and kidney tissue homogenates were used for antioxidant and lipid peroxidation assay. Relative change in expression of kidney injury molecule-1 (<i>KIM-1</i>) and crystal modulators genes in kidney tissues were evaluated. Tissue damage was assessed by histology studies of liver and kidney. Experimental group rats developed hyperoxaluria and crystalluria. Urine parameters, serum biochemistry, antioxidant profile, lipid peroxidation levels and gene expression analysis of experimental group II and III rats reflected acute kidney damage compared to group V rats. Histopathology results showed moderate hyperplasia in liver and severe interstitial inflammation in kidneys of group II and III than group V rats. Ingestion of naturally available oxalate enriched spinach extract successfully induced dietary hyperoxaluria and nephrocalcinosis in rats with minimal kidney damage.</p

Antioxidant activity of phenolic compounds from extracts of <i>Eucalyptus globulus</i> and <i>Melaleuca styphelioides</i> and their protective role on D-glucose-induced hyperglycemic stress and oxalate stress in NRK-49Fcells

<p>Phytochemicals serve as potential therapeutic agents for the prevention and treatment of diseases. In this study, we elucidate the renoprotective activity of compounds isolated from <i>Eucalyptus globulus</i> and <i>Melaleuca styphelioides</i> extracts in glucose- and oxalate-challenged NRK-49F cell model. The antioxidant potential of isolated compounds was evaluated based on their effect on antioxidant enzyme activities and lipid peroxidation levels. The results demonstrated that exposure of NRK-49F cells to glucose and oxalate stress augmented cell damage and attenuated antioxidant enzyme activities. The phytochemicals 2,2,8-trimethyl-6-formyl-chrom-3-ene-7-<i>O</i>-β-D-glucopyranoside, Cornusiin B and tellimagrandin I treatment restored antioxidant enzyme activity, significantly lowered lipid peroxidation levels and effectively protected cells from glucose and oxalate stress equivalent to the known antioxidant, <i>N</i>-acetyl cysteine. Pterocarinin A significantly reversed cellular damage owing to glucose stress. In conclusion, the compounds isolated from <i>E. globulus</i> and <i>M. styphelioides</i> showed potential cytoprotective and anti-oxidative property against glucose- and oxalate-induced oxidative stress in NRK-49F cells.</p