Zeolite Clinoptilolite: Therapeutic Virtues of an Ancient Mineral.

Zeolites are porous minerals with high absorbency and ion-exchange capacity. Their molecular structure is a dense network of AlO4 and SiO4 that generates cavities where water and other polar molecules or ions are inserted/exchanged. Even though there are several synthetic or natural occurring species of zeolites, the most widespread and studied is the naturally occurring zeolite clinoptilolite (ZC). ZC is an excellent detoxifying, antioxidant and anti-inflammatory agent. As a result, it is been used in many industrial applications ranging from environmental remediation to oral applications/supplementation in vivo in humans as food supplements or medical devices. Moreover, the modification as micronization of ZC (M-ZC) or tribomechanically activated zeolite clinoptilolite (TMAZ) or furthermore as double tribomechanically activated zeolite clinoptilolite (PMA-ZC) allows improving its benefits in preclinical and clinical models. Despite its extensive use, many underlying action mechanisms of ZC in its natural or modified forms are still unclear, especially in humans. The main aim of this review is to shed light on the geochemical aspects and therapeutic potentials of ZC with a vision of endorsing further preclinical and clinical research on zeolites, in specific on the ZC and its modified forms as a potential agent for promoting human brain health and overall well-being.

Comparison of synthetic zeolite catalysts and alumina binders administered intratracheally to rats.

An intratracheal (IT) screening assay was performed in rats on a series of aluminosilicate catalysts (synthetic zeolites) and alumina binders to compare their relative ability to cause pulmonary fibrosis and related changes. Before initiation of IT screens, both the uniformity of deposition and residence time of a prototype catalyst in the lung were determined. Subsequently, the test materials were instilled and animals were evaluated 6 mo later for lung volumes, pulmonary pressure-volume curves, pulmonary hydroxyproline (OHPro) content, lung weights, and histopathology. Negative controls were saline and glass beads; the positive control was quartz. The test materials were organic-free ZSM-5 crystals, organic form of ZSM-5 crystals, alumina-bound ZSM-5, nickel/ZSM-5/ Al2O3 binder, used nickel/ZSM-5/Al2O3 binder, nickel-tungsten/ZSM-5/Al2O3 binder, and Bayer pseudoboehmite. For each, groups of 12 male rats were dosed once with either 25 or 50 mg of ground particles (> or =95% less than 2.4 microm). Second to quartz, the sample of alumina caused the most pronounced pulmonary reactions at 6 mo after dosing. Therefore, the effects of four aluminas were subsequently compared (Bayer pseudoboehmite, Bayer gammaAl2O3, Ziegler pseudoboehmite, and Ziegler gammaAl2O3). The results support the idea of a lack of long-term effects from exposure to normal concentrations of these materials in the workplace. Also, the IT assay proved to be a very useful tool for ranking the relative effects of this series of zeolites and aluminas.

Effects of inorganic adsorbents and cyclopiazonic acid in broiler chickens.

Previous studies with cyclopiazonic acid (CPA) have indicated that this mycotoxin strongly adsorbs onto the surface of a naturally acidic phyllosilicate clay (AC). The objective of this study was to determine whether AC (and similar adsorbents) could protect against the toxicity of CPA in vivo. Acidic phyllosilicate clay, neutral phyllosilicate clay (NC, or hydrated sodium calcium aluminosilicate), and a common zeolite (CZ, or clinoptilolite) were evaluated. One-day-old broiler chicks consumed diets containing 0 or 45 mg/kg CPA alone or in combination with 1% AC, NC, or CZ ad libitum from Day 1 to 21. Body weight, feed consumption, feed:gain, hematology, serum biochemical values, and enzyme activities were evaluated. Compared to controls, CPA alone reduced body weight at Day 21 by a total of 26% and resulted in a significantly higher feed:gain ratio. Toxicity of CPA was also expressed through increased relative weights of kidney, proventriculus, and gizzard. Also, there were some alterations in hematology, serum biochemical values, and enzyme activities. Treatment with inorganic adsorbents did not effectively diminish the growth-inhibitory effects of CPA or the increased weights of organs, although there was some protection from hematological, serum biochemical, and enzymatic changes produced by CPA. The results of this study suggest that in vitro binding of CPA to clay does not accurately forecast its efficacy in vivo; the reasons for this discrepancy are not clear, but they may be related to differences in clay binding capacity and ligand selectivity for CPA in vitro vs in vivo. Predictions about the ability of inorganic adsorbents to protect chickens from the adverse effects of mycotoxins should be approached with caution and should be confirmed in vivo, paying particular attention to the potential for nutrient interactions.