Boron toxicity in higher plants: an update

In this review, emphasis is given to the most recent updates about morpho-anatomical, physiological, biochemical and molecular responses adopted by plants to cope with B excess. Boron (B) is a unique micronutrient for plants given that the range of B concentration from its essentiality to toxicity is extremely narrow, and also because it occurs as an uncharged molecule (boric acid) which can pass lipid bilayers without any degree of controls, as occurs for other ionic nutrients. Boron frequently exceeds the plant's requirement in arid and semiarid environments due to poor drainage, and in agricultural soils close to coastal areas due to the intrusion of B-rich seawater in fresh aquifer or because of dispersion of seawater aerosol. Global releases of elemental B through weathering, volcanic and geothermal processes are also relevant in enriching B concentration in some areas. Considerable progress has been made in understanding how plants react to B toxicity and relevant efforts have been made to investigate: (I) B uptake and in planta partitioning, (II) physiological, biochemical, and molecular changes induced by B excess, with particular emphasis to the effects on the photosynthetic process, the B-triggered oxidative stress and responses of the antioxidant apparatus to B toxicity, and finally (III) mechanisms of B tolerance. Recent findings addressing the effects of B toxicity are reviewed here, intending to clarify the effect of B excess and to propose new perspectives aimed at driving future researches on the topic.

The propolis and boric acid can be highly suitable, alone/or as a combinatory approach on ovary ischemia-reperfusion injury

PURPOSE

Ovarian ischemia-reperfusion (IR) damage continues to be a serious infertility problem. The oxidative stress plays central role in the development of IR injuries. Activation of antioxidants decreases IR injuries; however, the efficacy of antioxidant agents remains controversial. Unfortunately, there has been no evidence for medicinal use of boric acid (BA) and propolis (Prop) on ovarian IR injury on rats so far. This study will provide to reveal the potential applications of the Prop and BA in ovarian IR therapy.

METHODS

The Sprague-Dawley rats were randomized into five groups: I-control, II-IR, 3 h of ischemia and 3 h of reperfusion, III and IV-a signal dose of oral BA (7 mg/kg) and Prop (100 mg/kg) alone 1 h before induction of IR, V-Prop and BA together 1 h before induction of IR. SOD (superoxide dismutase), CAT (catalase), GSH (glutathione), MPO (myeloperoxidase), MDA (malondialdehyde), and IL-6 (interleukin-6) levels were quantified by ELISA and the TNF-α (tumor necrosis factor-α), 8-OHdG (8-hydroxylo-2'-deoxyguanosin) and Caspase-3 expressions were performed by immunohistochemical analyses.

RESULTS

BA and Prop pretreatment significantly reduced MPO, MDA, and IL-6 levels and pathologic score in IR rats, with no effects in control group. These agents used in therapy also decreased TNF-α, 8-OHdG and Caspase-3 protein expressions increased by IR. Furthermore, BA and Prop combination showed significant ameliorative effects on ovary injury caused by IR through acting as an antioxidant, anti-inflammatory and antiapoptotic agent.

CONCLUSION

BA and Prop alone and especially in combination could be developed as therapeutic agents against ovary IR injury.

The Effect of Mercury Chloride and Boric Acid on Rat Erythrocyte Enzymes

The aim of this study was to investigate the effects of mercury chloride and boric acid on rat (Wistar albino) erythrocyte: glucose 6-phosphate dehydrogenase (G6PD), 6-phosphoglucona-te dehydrogenase (6PGD), thioredoxin reductase (TrxR), glutathione reductase (GR) and glutathione S-transferase (GST) enzymes in vivo, and the rat erythrocyte G6PD enzyme in vitro. In the in vivo study, 24 male rats were divated into three different groups: control (C), mercury chloride (M), and mercury chloride + boric acid (M + BA). At the completion of this study, a significant degree of inhibition for both G6PD and GST enzyme activity was observed in the M groups when compared to the C group (p < 0.05), and no significant effect was observed in the 6PGD enzyme. However, there was significantly increased TrxR and GR enzyme activity of both the M and M + BA groups (p < 0.05). In the in vitro study, the G6PD enzyme from rat erythrocytes was purified with 2',5'-ADP Sepharose-4B affinity chromatography, and the effect of both mercury chloride and boric acid on the enzyme activity was investigated. The results showed that boric acid increased the G6PD enzyme activity while the mercury ions that inhibited the enzyme activity (IC₅₀ values of 346 μM and K_i values of 387 μM) were noncompetitive.

Boron containing compounds promote the survival and the maintenance of pancreatic β-cells

Diabetes mellitus is worldwide disease. The life of diabetic patients are dependent on exogenous insulin. Pancreas or particularly islet transplantations are performed for reducing external insulin dependency. External substances are also used to protect the β-cells from the death or increase insulin secretion. In the current study, two different boron containing compounds (sodium pentaborate pentahydrate-NaB and boric acid-BA) were investigated for their effect on pancreatic cells in terms of pro-apoptotic and anti-apoptotic markers, genes related to insulin production mechanism, pancreatic development and glucose metabolism, some antioxidant enzymes, and genes for the initiation of diabetes, insulin secretion and antioxidant enzyme activities in vitro. The results revealed that boron containing compounds did not lead to apoptosis. On the contrary, they increased cell viability, antioxidant enzyme activities and the level of genes related to insulin production. Overall evaluation, data in the current study showed that boron containing compounds might be promising therapeutic agents for type 1 diabetes. However, additional investigations are strictly needed to elucidate molecular mechanisms of boron containing compounds.

Cardiac arrest induced by the intentional ingestion of boric acid and mirtazapine treated by percutaneous cardiopulmonary bypass: a case report

Background

Mirtazapine has a good tolerability and safety profile that demonstrates several benefits over other antidepressants and it is associated with few fatalities. Boric acid is an odorless white powder that is generally not recognized as a poisonous substance. We report a case of cardiac arrest induced by the intentional ingestion of mirtazapine, boric acid, and sennosides, by a patient who required percutaneous cardiopulmonary bypass.

Case presentation

Our patient was a 49-year-old Japanese woman with a history of depression; she was found in an unconscious state after ingesting boric acid (unknown amount), mirtazapine (1950 mg), and sennosides (780 mg). On arrival, she was in a deep coma with marked hypotension induced by atrial fibrillation, tachycardia, and diffuse hypokinetic cardiac motion. She had systemic diffuse erythema. Her serum concentrations of boric acid and mirtazapine on arrival were 560.49 mg/L and 1270 ng/mL, respectively. She experienced repeated cardiac arrest, and was therefore treated with tracheal intubation, mechanical ventilation, percutaneous cardiopulmonary bypass, and continuous hemodialysis filtration. Stable circulation and respiration and a normal kidney function were finally obtained and she was transferred to a local medical facility in a persistent unconscious state.

Conclusions

This is the first case of a return of spontaneous circulation after cardiac arrest induced by the intentional ingestion of boric acid and mirtazapine, requiring percutaneous cardiopulmonary bypass for survival. To maintain cerebral perfusion during percutaneous cardiopulmonary bypass, even in a prolonged state of cardiac arrest induced by overdose, is medically, ethically, and economically challenging.

Electrocoagulation of tetrafluoroborate (BF4-) and the derived boron and fluorine using aluminum electrodes

Tetrafluoroborate anion (BF₄^-) is found in the streams of flue-gas desulfurization and borosilicate glasses etching which deteriorates water quality through slow hydrolysis into boric acid and fluoride. Decomposition and electrocoagulation (EC) of BF₄^- were studied using metallic aluminum as the sacrificial electrode. The dissolved Al(III) from the anode could efficiently decompose BF₄^- in forms of fluoroaluminate complexes, and the derived boric acid and fluoride ion were removed by sweep flocculation. Major variables were investigated to optimize EC, including the reaction pH, initial concentration of BF₄^-, current density and electrolyte type. The mechanism of EC process was elucidated with the kinetics of consecutive reactions. Experimental results suggested that the removal of BF₄^- and total fluoride were less influenced by pH, and that of total boron reached a maximum at pH 8 which favored the surface complexation between borate species and EC precipitates. Under the conditions: [BF₄^-]₀ = 9.3 mM, [NaCl] = 10 mM, pH = 8.0, current density = 5 mA/cm², 98.3% of BF₄^- was decomposed and the removal of total fluoride and boron attained 98.2% and 74.1%, respectively within 3 h. EC using the Al electrode outperformed the conventional chemical coagulation and reduced the levels of BF₄, B(OH)₃ and F^- in aqueous solution synergically.

Environmental boron exposure does not induce DNA damage in lymphocytes and buccal cells of females: DNA damage in lymphocytes and buccal cells of boron exposed females

Boron (B) compounds are essential for plants and animals and beneficial for humans in nutritional amounts. I animals and humans increasing evidence have shown beneficial effects on B compounds on nutrition and on antioxidant status. The genotoxic effects of environmental B exposure in women living in boron-rich and boron-poor areas was examined in this study. For this purpose, the DNA damage in the lymphocytes and buccal cells of females were assessed by Comet and micronucleus (MN) assays respectively. No significant difference was observed in the DNA damage of the lymphocytes of B exposed groups of female volunteers in Comet assay. Even buccal micronucleus (MN) frequency observed in the high exposure group was significantly lower than the low exposure group (p < 0.05). The results of this study came to the same conclusions of the previous studies that boron does not induce DNA damage even under extreme exposure conditions.

Hepato-preventive and anti-apoptotic role of boric acid against liver injury induced by cyclophosphamide

This study aims to examine cyclophosphamide (CP) exsposure associated toxicity on rat livers and the likely defensive effects of boric acid (BA). The rats used in this study were divided into four groups: control group, CP group, BA group, and BA + CP group. The present study was carried out using routine histological H&E stain, immunohistochemical stain caspase-3 as apoptotic marker, serum biochemical analysis for liver function markers (alanine transaminase (ALT), aspartate transaminase (AST) and alkalen phosphatase (ALP)), oxidative stress markers (total oxidant status (TOS), oxidative stress index (OSI) and total antioxidant capacity marker (TAC)). In the CP group, the levels of ALT, AST, ALP, TOS, OSI and caspase-3 increased whereas TAC levels decreased compared with the control group. In the BA + CP group, the levels of ALT, AST, ALP, TOS, OSI and caspase-3 decreased whereas TAC levels increased compared with the CP group. The histopathological evaluation of light microscope images and immunohistochemical caspase-3 activity in the BA + CP group were found to be decrease compared with those in the CP group. In conclusion, BA was successful in defending the liver against apoptosis and histopathological changes that are attributable to CP.

Boron and pigment content in alfalfa affected by nano fertilization under calcareous conditions

Boron is among the necessary nutrients for plant growth and yield production, and it can improve the nutritional properties of forage crops. However, at higher levels it maybe toxic adversely affecting plant growth and forage quality. Plant boron concentration is affected by different parameters including boron fertilization, soil, climate, plant species, etc. A new era in the field of plant fertilization is the use of nano technology. Accordingly, a factorial field experiment on the basis of a complete block design in six replicates was conducted in a 300-hactare agro-industry area. The objectives were to investigate the effects of different boron treatments on alfalfa (Medicago sativa L.): 1) boron concentration, and 2) pigment contents including chlorophyll a, b, total, and carotenoids. Six regions with different properties were selected for the experiment; the soil samples were collected using GPS. The experimental treatments including: 1) soil type (S1-S6), 2) boron sources including boric acid (B1) and nano boron fertilization (B2), and 3) number of spraying (zero-, one-, two-, and three-time) were tested. The nano structure of boric acid-copper in an aqueous medium was produced using the chemical reduction method. The results indicated that soil type, boron source and number of spraying significantly affected (P ≤ 0.01) alfalfa boron concentration and pigment content. The mean of alfalfa boron concentration by B1 and B2 was 103.52 and 111.52% higher than control. The three-time spraying significantly increased B concentration related to the other spraying treatments (P ≤ 0.05) as it resulted in a 207.81% increase compared with the control treatment. The three-time spraying resulted in the highest increase of pigment contents (P ≤ 0.05) including chlorophyll a, b, total, and carotenoids compared with the other treatments. Although the highest boron and pigment contents were resulted by the three-time spraying, the combined use of B2 and the two-time spraying was the most optimum treatment (non-toxic) significantly increasing alfalfa boron and pigment contents (P ≤ 0.05). It would be possible to produce alfalfa at large amounts and with suitable forage quality using boron nano fertilization (synthesized and tested in this research work) under calcareous conditions.

Repeated dose inhalation developmental toxicity study in rats exposed to cellulose insulation with boric acid additive

Cellulose insulation (CI), a common building material, is a mixture of cellulose fibers and borates. Borates are approximately 20% of the product weight and act as a flame retardant. Given possible exposure to workers and consumers, an inhalation toxicity study was conducted following Organization for Economic Co-operation and Development (OECD) 414 for Prenatal Development Toxicity to evaluate if CI is a developmental toxicant. Pregnant female rats were exposed by nose-only inhalation to CI aerosols containing 20% boric acid for six h/day, from gestational day (GD) 6-19, and fetuses were evaluated for developmental parameters. Respirable CI was produced by grinding to produce respirable particles (MMAD 2.7-2.9 µm, geometric standard deviations (GSD) 1.9-2.6), which were then aerosolized. Target air concentrations were 15, 90, and 270 mg CI/m³. Controls were exposed to air only. Slight body weight reductions (average decrease <7% vs. control) were observed in male and female GD 20 fetuses in the mid and high dose groups. No embryo/fetal developmental toxicity or alterations in any other measured variable were reported at any dose. The no observed adverse effect level (NOAEL) for developmental outcomes was 270 mg/m³.

Boric Acid Activation of eIF2α and Nrf2 Is PERK Dependent: a Mechanism that Explains How Boron Prevents DNA Damage and Enhances Antioxidant Status

Boron is abundant in vegetables, nuts, legumes, and fruit and intake is associated with reduced risk of cancer and DNA damage and increased antioxidant status. Blood boric acid (BA) levels are approximately 10 μM BA in men at the mean US boron intake. Treatment of DU-145 human prostate cancer cells with 10 μM BA stimulates phosphorylation of elongation initiation factor 2α (eIF2α) at Ser51 leading to activation of the eIF2α/ATF4 pathway which activates the DNA damage-inducible protein GADD34. In the present study, we used MEF WT and MEF PERK (±) cells to test the hypothesis that BA-activated eIF2α phosphorylation requires protein kinase RNA-like endoplasmic reticulum kinase (PERK) and activates Nrf2 and the antioxidant response element (ARE). BA (10 μM) increased phosphorylation of eIF2α Ser51 in MEF WT cells at 1 h, but not in MEF Perk -/- cells exposed for as long as 6 h. GCN2 kinase-dependent phosphorylation of eIF2α Ser51 was activated in MEF PERK -/- cells by amino acid starvation. Nrf2 phosphorylation is PERK dependent and when activated is translocated from the cytoplasm to the nucleus where it acts as a transcription factor for ARE. DU-145 cells were treated with 10 μM BA and Nrf2 measured by immunofluorescence. Cytoplasmic Nrf2 was translocated to the nucleus at 1.5-2 h in DU-145 and MEF WT cells, but not MEF PERK -/- cells. Real-time PCR was used to measure mRNA levels of three ARE genes (HMOX-1, NQO1, and GCLC). Treatment with 10 μM BA increased the mRNA levels of all three genes at 1-4 h in DU-145 cells and HMOX1 and GCLC in MEF WT cells. These results extend the known boric acid signaling pathway to ARE-regulated genes. The BA signaling pathway can be expressed using the schematic [BA + cADPR → cADPR-BA → [[ER]_i Ca²⁺↓] → 3 pathways: PERK/eIF2αP → pathways ATF4 and Nrf2; and [[ER]_i Ca²⁺↓] → ER stress → ATF6 pathway. This signaling pathway provides a framework that links many of the molecular changes that underpin the biological effects of boron intake.

In vitro activity of EDTA and TOL-463 against Neisseria gonorrhoeae

Neisseria gonorrhoeae quickly develops drug resistance. Time-kill curves revealed that EDTA and TOL-463 inhibit growth similar to penicillin, ciprofloxacin, and azithromycin. Furthermore, synergistic and additive antimicrobial interactions occurred when EDTA and TOL-463 were combined with penicillin or azithromycin, respectively, suggesting that further investigations into these unconventional antimicrobials may be advantageous.

Antifibrotic Effect of Boric Acid in Rats with Epidural Fibrosis

BACKGROUND

Epidural fibrosis is a major problem after spine surgery, with some patients having recurrent symptoms secondary to excessive formation of scar tissue resulting in neurologic compression. We used a rat laminectomy model to determine if topical application of boric acid could be helpful in the prevention of epidural fibrosis.

METHODS

Rats were randomly assigned to 2 control and 2 experimental groups (n = 8 for each group). The negative control group received no surgery, and the positive control group underwent laminectomy only. Experimental groups were classified according to the study agents applied onto the dura mater after laminectomy at the L3 level: 2.5% boric acid solution and 5% boric acid solution. The extent of epidural fibrosis was assessed 4 weeks later macroscopically and histopathologically.

RESULTS

Boric acid reduced epidural fibrosis in rats after laminectomy. The effect of 5% boric acid solution was more pronounced (P < 0.05) compared with the 2.5% solution.

CONCLUSIONS

The antifibrotic effect of boric acid solution for the prevention of epidural fibrosis suggests that boric acid should be further evaluated in future studies for the prevention of epidural fibrosis.

Effects of boric acid on bone formation after maxillary sinus floor augmentation in rabbits

PURPOSE

Augmentation of the maxillary sinus floor with bone grafting is commonly used for successful treatment of edentulous posterior maxilla with dental implants, and it is essential to maintain good bone volume and quality for long-term success of dental implants. The aim of this experimental study was to investigate the local and systemic effects of boric acid on new bone formation after maxillary sinus floor augmentation (MSFA).

MATERIALS AND METHODS

Twenty-four male, New Zealand rabbits were randomly divided into three groups with eight rabbits each, and bilateral MSFA was performed in each animal. An autogenous bone/xenograft mixture was used to augment the maxillary sinuses in each group. Group 1 was determined as control with no additional materials, whereas 3 mg/kg boric acid (BA) was added to the mixture in group 2, and 3 mg/kg boric acid solution added to drinking water daily in group 3.

RESULTS

The animals were sacrificed and also histologic, histomorphometric, and immunnohistochemical analyses were performed at weeks 4 and 8. At week 4, bone regeneration was better in the local BA group than in the control and systemic BA groups (p < 0.05). However, no significant difference was found among the groups in terms of bone regeneration at the end of week 8 (p > 0.05).

CONCLUSION

Significant higher new bone formation was revealed by BA at early healing especially with local application. BA may be a therapeutic option for improving the bone regeneration.

Boric acid protects against cyclophosphamide-induced oxidative stress and renal damage in rats

The worldwide increase in the rate of cancer incidence also leads to a significant increase in the use of chemotherapeutic agents. Unfortunately, the optimal clinical usefulness of these agents is heavy restricted by a high incidence of several organ toxicity and as well reason oxidative stress and bring about changing in antioxidant status. Kidney toxicity is a side effect often encountered with cyclophosphamide (CPM) which is commonly used in most cancer chemotherapy. The present study aims on the assessment of the probable defensive efficacy of Boric acid (BA) against CPM-induced oxidative stress and renal damage in rats. Based upon our investigation results with oxidative stress markers and light microscopic findings, it can be concluded that BA significantly reduced CPM induced oxidative stress and renal damage. As far as we know, high dose (200 mg/kg) of BA are the first study on the prevention of kidney damage caused by CPM. It is thought that the renoprotective effects of BA may be due to an increase in the activity of the antioxidant protection system and also inhibition of lipid per oxidation.

Influence of boric acid on energy metabolism and stress tolerance of Candida albicans

Boron presents at physiological pH in the form of boric acid (BA), a molecule that has both positive and negative effects on biological processes. In medicine, BA is used as a topical treatment for vaginal yeast infections by Candida species because of its well-documented but poorly understood effect on inhibition of growth in general and of invasive, hyphal growth in particular. The present study examines the influence of BA on carbohydrate energy metabolism of this common human pathogen. Starting from previous findings about an inhibition of key NAD-dependent enzymes by BA in vitro, we confirmed that such an inhibition occurs in permeabilized C. albicans cells. Cultures growing even with moderate concentrations of BA experience mitochondrial failure, increase ethanol production from glucose and decrease the deposition of carbohydrate stores in the form of glycogen. Cells growing on the non-fermentable, FAD-generating carbon source lactate have a higher BA tolerance, which suggests that the toxicity of BA is rooted in an inhibition of NAD-dependent reactions and the increased production of ethanol. Boric acid exposure sensitizes C. albicans selectively to the toxic effects of ethanol. This additive effect suggests that the endogenously produced ethanol increases the load on ethanol resistance mechanisms. Lastly, combination studies showed no interactions of BA with common antifungal drugs, meaning that addition of BA to topical formulations can provide an additive antifungal effect regardless of the chosen active ingredient.

Several effects of boron are induced by uncoupling steroid hormones from their transporters in blood

Boron is increasingly added to food supplements due to multiple effects that have been reported in mammals after boric acid administration. Among these effects are inflammatory process control, bone and muscle strength enhancement, protein expression regulation, and a decreased risk of developing some pathologies in which these processes are key, such as osteoporosis, dermatological inflammatory non-infectious maladies and diseases affecting the central nervous system. Experimental data have suggested that steroid hormone levels in plasma change after boric acid administration, but a clear mechanism behind these variations has not been established. We analyzed possibilities for these changes and hypothesized that boric acid disrupts the interactions between steroid hormones and several carriers in plasma. In particular, we proposed that there is an uncoupling of the interactions between sex hormone binding globulin (SHBG) and estrogens and testosterone and that there are alterations in the binding of hydrophobic ligands by other carrier proteins in plasma. Further experimental and computational studies are required to support the hypothesis that boric acid and probably other boron-containing compounds can displace steroid hormones from their plasma carriers. If such phenomena are confirmed, boron administration with a clear mechanism could be employed as a therapeutic agent in several diseases or physiological events that require modulation of steroid hormone levels in plasma.

Simultaneous Quantitation of Boric Acid and Calcium Fructoborate in Dietary Supplements by HPTLC-Densitometry

The paper describes a new, simple, selective and precise high-performance thin-layer chromatographic (HPTLC) method for the simultaneous identification and quantitative determination of boric acid (BA) and calcium fructoborate (CFB) in bulk and tablet/capsule dosage forms of dietary supplements. HPTLC silica gel G 60 F₂₅₄ precoated glass plates were used as the stationary phase. The mobile phase consisted of 2-propanol-water 8:2 (v/v). The two boron-based compounds were adequately separated with the R_f values of 0.83 ± 0.01 (BA) and 0.59 ± 0.01 (CFB).

Methylboronic acid fertilization alleviates boron deficiency symptoms in Arabidopsis thaliana

Our results showed that methylboronic acid is capable of alleviating boron deficiency, enhancing plant growth, and is less toxic than boric acid at higher concentrations. Boron is an essential plant micronutrient and its deficiency occurs in several regions globally, resulting in impaired plant growth. Boron fertilization is a common agricultural practice, but the action range of boron is narrow, sharply transitioning from deficiency to toxicity. Boric acid (BA) is the most common chemical form used in agriculture. In this work, we describe that methylboronic acid (MBA) is capable of alleviating boron deficiency in Arabidopsis. MBA is a boronic acid, but does not naturally occur in soils, necessitating synthesis. Other boronic acids have been described as boron competitors in plants, inhibiting auxin biosynthesis and root development. MBA is more water-soluble than BA and delivers the same amount of boron per molecule. We observed that Arabidopsis seedlings grown in the presence of MBA presented higher numbers of lateral roots and greater main root length compared to plants grown in BA. In addition, root hair length and leaf surface area were increased using MBA as a boron fertilizer. Finally, MBA was less toxic than BA at high concentrations, producing a slight reduction in the main root length but no decrease in total chlorophyll. Our results open a new opportunity to explore the use of a synthetic form of boron in agriculture, providing a tool for future research for plant nutrition.

The toxic effect of gallic acid on biochemical factors, viability and proliferation of rat bone marrow mesenchymal stem cells was compensated by boric acid

OBJECTIVE

Gallic acid (GA) and boron are found in many plants. Our previous studies showed 6 ng/ml boric acid (BA) had positive effect on biochemistry of rat bone marrow mesenchymal stem cells (MSCs) and their osteogenic differentiation. Therefore, we investigate the effect of different doses of GA alone and in the presence of BA on MSCs.

MATERIALS AND METHODS

the viability of MSCs was assayed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and trypan blue at 12, 24 and 36 h in presence of different concentration of GA. Then 30 and 120 μM of GA as well as 6 ng/ml of BA in 36 h were selected for further study. The proliferation, Morphology, sodium and potassium level, concentration of calcium, activity of alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) as well as malondialdehyde (MDA) concentration, total antioxidant capacity (FRAP) and activity of superoxide dismutase (SOD) and catalase (CAT) were estimated.

RESULT

Results showed GA alone reduced viability, proliferation, nuclear diameter and cytoplasm area. In addition, GA showed anaerobic metabolic shift but no change in MDA and scavenging enzymes. Both concentration of GA caused elevation of FRAP, whereas only at 120 μM increased the sodium-potassium and reduced calcium. The co-treatment of GA and BA improves the viability, proliferation and morphology of the cells. In addition, co-treatment compensated the metabolic shift caused by GA and could balance the potassium level and FRAP as it was raised by GA.

CONCLUSION

Although GA content of tea is harmful to the cells but simultaneous consumption of fruits and vegetables as a rich source of boron might compensate the damaging effect of GA.

Boron Uptake Assay in Xenopus laevis Oocytes

Boron (B) is essential for plant growth and taken up by plant roots as boric acid. Under B limitation, B uptake and translocation in plants are dependent on the boric acid channels located in the plasma membrane. Xenopus leavis oocyte is a reliable heterologous expression system to characterize transport activities of boric acid channels and related major intrinsic proteins (aquaporins). Here, we outline the protocols for expression of boric acid channels and boric acid uptake assay in Xenopus leavis oocytes.

The importance of boron in biological systems

Boron is an essential element for plants and probably essential for human and animal health. Boron has a broad range of physiological effects on biological systems at low concentrations, whereas it is toxic to at high concentrations. Eventhough there are many studies on boron's biological effects and toxicity, more information is needed to understand the mechanisms of its action. The aim of the current work is to review boron's function, transport and toxicity in different biological systems.

Lugol's solution eradicates Staphylococcus aureus biofilm in vitro

OBJECTIVES

The aim of the study was to evaluate the antibacterial efficacy of Lugol's solution, acetic acid, and boric acid against Staphylococcus aureus biofilm.

METHODS

The efficacy of Lugol's solution 1%, 0.1%, and 0.05%, acetic acid 5% or boric acid 4.7% for treatment of Staphylococcus aureus biofilm in vitro was tested using 30 clinical strains. Susceptibility in the planktonic state was assessed by disk diffusion test. Antiseptic effect on bacteria in biofilm was evaluated by using a Biofilm-oriented antiseptic test (BOAT) based on metabolic activity, a biofilm bactericidal test based on culturing of surviving bacteria and confocal laser scanning microscopy combined with LIVE/DEAD staining.

RESULTS

In the planktonic state, all tested S. aureus strains were susceptible to Lugol's solution and acetic acid, while 27 out of 30 tested strains were susceptible to boric acid. In biofilm the metabolic activity was significantly reduced following exposure to Lugol's solution and 5% acetic acid, while boric acid exposure led to no significant changes in metabolic activities. In biofilm, biocidal activity was observed for Lugol's solution 1% (30/30), 0.1% (30/30), and 0.05% (26/30). Acetic acid and boric acid showed no bactericidal activity in this test. Confocal laser scanning microscopy, assessed in 4/30 strains, revealed significantly fewer viable biofilm bacteria with Lugol's solution (1% p < 0.001, 0.1% p = 0.001 or 0.05% p = 0.001), acetic acid 5% for 10 min (p = 0.001) or 30 min (p = 0.015), but not for acetic acid for 1 min or boric acid.

CONCLUSION

Lugol's solution 1.0% and 0.1% effectively eradicated S. aureus in biofilm and could be an alternative to conventional topical antibiotics where S. aureus biofilm is suspected such as external otitis, pharyngitis and wounds.

An improved solvent-free synthesis of flunixin and 2-(arylamino) nicotinic acid derivatives using boric acid as catalyst

A simple solvent-free protocol for the preparation of flunixin, a potent non-narcotic, non-steroidal anti-inflammatory drugs is reported using boric acid as catalyst. Its salt, flunixin meglumine are then prepared under reflux in EtOH. This sustainable method are then extended for the synthesis of a series of 2-(arylamino) nicotinic acid derivatives. The present protocol combines non-hazardous neat conditions with associated benefits like excellent yield, straightforward workup, and use of readily available and safe catalyst in the absence of any solvent, which are important factors in the pharmaceutical industry. The pathway for catalytic activation of 2-chloronicotic acid with boric acid was also investigated using Gaussian 03 program package.

Hybrid films of chitosan, cellulose nanofibrils and boric acid: Flame retardancy, optical and thermo-mechanical properties

Chitosan (CS), cellulose nanofibrils (CNF) and boric acid, the latter of which was used as flame retardant, were combined in transparent, hybrid films that were produced by solvent casting. The flammability and the thermal stability of the films were studied with respect to the loading of the inorganic component. Chitosan films displayed fire retardancy properties, which were enhanced in the presence of boric acid. CNF films, in contrast to those from chitosan, were readily flammable; however, when combined with boric acid (30w%), they became self-extinguishing. Most remarkably, bicomponent films comprising CNF and chitosan, displayed better fire retardancy than that of neat CS films. Moreover, boric acid improved the thermal stability of the bicomponent films. The tensile strength and Young's modulus of CS, CNF and CS-CNF films improved at intermediate boric acid addition, although a negative effect on elongation was observed.