The Fructoborates: Part of a Family of Naturally Occurring Sugar–Borate Complexes—Biochemistry, Physiology, and Impact on Human Health: a Review

Abstract

Sugar–borates (SBs) are mono- or di-sugar–borate esters (SBEs) comprised of one or two monosaccharide molecules linked to a boron (B) atom. SBEs occur naturally in commonly consumed herbs, vegetables, fruits, seeds, and nuts and, other than greatly varying levels of B found in local drinking water, are the primary natural dietary sources of B-containing molecules in humans. To date, the most studied SBE is calcium fructoborate (CaFB). CaFB represents an important example of how organic B-containing molecules are significantly distinct from their inorganic counterparts. During these past two decades, CaFB has been researched for its physical and biochemical characteristics, safety, and clinical outcomes. Results of these researches are presented and discussed herein. CaFB has been characterized using Fourier-transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), high-performance thin-layer chromatography (HPTLC), nuclear magnetic resonance (NMR), liquid chromatography–multistage accurate mass spectrometry (LC-MSn), X-ray diffraction (XRD), Raman spectroscopy, and inductively coupled plasma (ICP) in non-biological and biological specimens. Potential health benefits of CaFB have been clinically investigated in pilot and efficacy studies demonstrating (i) significant reductions in knee discomfort and improved flexibility within 7, 14, and 90 days and (ii) significant effect on blood levels of inflammatory, cardiovascular, and other biomarkers. These studies support the use of CaFB as a dietary supplement for the management of joint discomfort. CaFB is presented here in order to illustrate how physiological benefits are imparted by distinct organic boron-containing molecules rather than solely by the element B itself. Considering recent National Health and Nutrition Examination Survey (NHANES) data reporting increases in age-related joint pain and an increasing elderly demographic, SBEs offer potential for safe, natural, and effective management of joint discomfort and improved mobility in human and animal health applications. Several of these studies may also open new opportunities for use of SBEs for health benefits beyond joint health.

Selected physiological effects of boron compounds for animals and humans. A review

“…Recent studies strongly documented that only plants have the ability to metabolize inorganic boron compounds (like boric acid or borates) and to convert these boron compounds into mono-or di-sugar-borate esters (SBEs), e.g., glucose and fructose borate esters, bis-sucrose borate esters, pectic polysaccharide borate esters or sugar alcohol borate esters (Hunter et al, 2019). In contrast, animals and humans do not have the capacity to transform boric acid or borates into SBEs (Hunter et al, 2019). SBEs are found in herbs, seeds, fresh leafy vegetables, fruits, legumes, certain nuts, wine, cider, beer and especially in flaxseed sprouts, dandelion root and raisin.…”

“…Vegetables, fruits and honey are the basic sources of fructoborates (fructoborate esters, FB), mainly in the form of calcium (Ca 2+ ) fructoborate complex (Pietrzkowski et al, 2014;Donoiu et al, 2018). Fructoborates have positive synergic interactions with ions of Ca, Mg, Zn, Fe and Cu; FB have a better interaction capacity with glycoproteins versus that of the boric acid or borate (Mogoşanu et al, 2016;Hunter et al, 2019). In contrast, FB are antagonized by Si (as orthosilicic acid), iodine and fluoride (Hunter et al, 2019).…”

“…Fructoborates have positive synergic interactions with ions of Ca, Mg, Zn, Fe and Cu; FB have a better interaction capacity with glycoproteins versus that of the boric acid or borate (Mogoşanu et al, 2016;Hunter et al, 2019). In contrast, FB are antagonized by Si (as orthosilicic acid), iodine and fluoride (Hunter et al, 2019). Fructoborate complexes with metal ions like Zn, Mg, Fe or Cu and a protonated diester fructoborates (HBF; the FB complex with H + ) have negligible physiological significance as compared to calcium FB complex (CaFB).…”

“…Fructoborate complexes with metal ions like Zn, Mg, Fe or Cu and a protonated diester fructoborates (HBF; the FB complex with H + ) have negligible physiological significance as compared to calcium FB complex (CaFB). A novel zinc-boron complex (ZnFB) reveals low cytotoxic effect (Hunter et al, 2019). It must be stated that CaFB (Ca[(C 6 H 10 O 6 ) 2 B] 2 •4H 2 O) is the most common natural sugar-borate ester complex, typically manifested as the specific bis-fructose ester (Tepedelen et al, 2017).…”

“…In the USA, CaFB is applied as a supplement into human diets for bone health and modulation of symptoms of arthritis and joint degeneration. Moreover, it was revealed that CaFB added to human diets has a beneficial impact on various anti-inflammatory processes (Hunter et al, 2019). CaFB regulates macrophage production of inflammatory mediators, inhibits the evolution of diseases associated with endotoxins and suppresses cytokine formation.…”