Partial Purification of Soluble Lipoxygenase of Sunflower Cotyledons: Action of Boron on the Enzyme and Lipid Constituents

Mineral Micronutrients in Asthma

Asthma represents one of the most common medical issues in the modern world. It is a chronic inflammatory disease characterized by persistent inflammation of the airways and disturbances in redox status, leading to hyperresponsiveness of bronchi and airway obstruction. Apart from classical risk factors such as air pollution, family history, allergies, or obesity, disturbances of the levels of micronutrients lead to impairments in the defense mechanisms of the affected organism against oxidative stress and proinflammatory stimuli. In the present review, the impact of micronutrients on the prevalence, severity, and possible risk factors of asthma is discussed. Although the influence of classical micronutrients such as selenium, copper, or zinc are well known, the effects of those such as iodine or manganese are only rarely mentioned. As a consequence, the aim of this paper is to demonstrate how disturbances in the levels of micronutrients and their supplementation might affect the course of asthma.

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.

Comparative effects of boric acid and calcium fructoborate on breast cancer cells

Recent studies suggested that boron has a chemo-preventive role in prostate cancer. In the present report, we investigated the effects of calcium fructoborate (CF) and boric acid (BA) on activation of the apoptotic pathway in MDA-MB-231 human breast cancer cells. Exposure to BA and CF inhibited the proliferation of breast cancer cells in a dose-dependent manner. Treatment with CF but not BA resulted in a decrease in p53 and bcl-2 protein levels. Furthermore, after the treatment with CF, augmentation of pro-caspase-3 protein expression, cytosolic cytochrome c level, and caspase-3 activity were observed, indicating apoptotic cell death induction. This was also demonstrated by terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate nick-end-labeling assay. In conclusion, our data provide arguments to the fact that both BA and CF inhibited the growth of breast cancer cells, while only CF induced apoptosis. Additional studies will be needed to identify the underlying mechanism responsible for the observed cellular responses to these compounds and to determine if BA and CF may be further evaluated as chemotherapeutic agents for human cancer.

Boron concentrations in milk from mothers of full-term and premature infants

BACKGROUND

Boron is a bioactive element that satisfies several of the criteria for essentiality in humans.

OBJECTIVE

The objective was to establish the profile of boron metabolism in human milk.

DESIGN

Lactating mothers of premature (PRT; n = 10, <2000 g birth weight, <37 wk gestation) and full-term (FT; n = 10, >2500 g, 39-41 wk gestation) infants living in St John's, Canada, collected milk samples once a week for 12 wk. Samples were analyzed for boron, copper, iron, selenium, and zinc by atomic emission or absorption spectrometry after wet-ash digestion with nitric acid and hydrogen peroxide in polytetrafluoroethylene tubes.

RESULTS

A mixed-model analysis of variance indicated that boron concentrations were stable in full-term (30 and 28 mug/L milk; P = 0.5) but not in preterm (37 and 27 mug/L; P = 0.01) milk between weeks 1 and 12, respectively. As expected, there were reductions in the concentrations of copper (FT: 651 to 360 mug/L, P < 0.0001; PRT: 542 to 425, P = 0.05), iron (FT: 355 to 225 mug/L, P = 0.0003; PRT: 406 to 287, P = 0.002), selenium (FT: 26.9 to 18.6 mug/L, P < 0.0001; PRT: 28.7 to 20.4, P < 0.0001), and zinc (FT: 4060 to 1190 mug/L, P < 0.0001; PRT: 5970 to 1270, P < 0.0001) over time.

CONCLUSIONS

The stable milk boron concentrations over time suggest that boron may be under homeostatic control. The patterns of change in copper, iron, selenium, and zinc concentrations in milk differ from those of boron. Further research is needed to elucidate the mechanism of milk boron secretion.

Regulation of enzymatic activity: one possible role of dietary boron in higher animals and humans

It is well established that vascular plants, diatoms, and some species of marine algal flagellates have acquired an absolute requirement for boron (B), although the primary role remains unknown. Discovery of naturally occurring organoboron compounds, all ionophoric macrodiolide antibiotics with a single B atom critical for activity, established at least one biochemical role of B. The unusual nature of B chemistry suggests the possibility of a variety of biological roles for B. At physiological concentrations and pH, B may react with one N group or one to four hydroxyl groups on specific biological ligands with suitable configuration and charge to form dissociable organoboron compounds or complexes. Suitable ligands include pyridine (e.g., NAD+ or NADP) or flavin (e.g., FAD) nucleotides and serine proteases (SP). B reacts with the cis adjacent hydroxyls on the ribosyl moiety of the nucleotides or, in the serine proteases, the N on the imidazole group of histidine or the hydroxyl group on the serine moiety. Reversible inhibition by B of activity of SP or oxidoreductases that require pyridine or flavin nucleotides is well known. Therefore, a proposed essential role for B is as a regulator of relevant pathways, including respiratory burst, that utilize these enzymes.