Abstract
Silicon (Si) is the most abundant element present in the Earth's crust besides oxygen. However, the exact biological roles of silicon remain unknown. Moreover, the ortho-silicic acid (H4SiO4), as a major form of bioavailable silicon for both humans and animals, has not been given adequate attention so far. Silicon has already been associated with bone mineralization, collagen synthesis, skin, hair and nails health atherosclerosis, Alzheimer disease, immune system enhancement, and with some other disorders or pharmacological effects. Beside the ortho-silicic acid and its stabilized formulations such as choline chloride-stabilized ortho-silicic acid and sodium or potassium silicates (e.g. M2SiO3; M= Na,K), the most important sources that release ortho-silicic acid as a bioavailable form of silicon are: colloidal silicic acid (hydrated silica gel), silica gel (amorphous silicon dioxide), and zeolites. Although all these compounds are characterized by substantial water insolubility, they release small, but significant, equilibrium concentration of ortho-silicic acid (H4SiO4) in contact with water and physiological fluids. Even though certain pharmacological effects of these compounds might be attributed to specific structural characteristics that result in profound adsorption and absorption properties, they all exhibit similar pharmacological profiles readily comparable to ortho-silicic acid effects. The most unusual ortho-silicic acid-releasing agents are certain types of zeolites, a class of aluminosilicates with well described ion(cation)-exchange properties. Numerous biological activities of some types of zeolites documented so far might probably be attributable to the ortho-silicic acid-releasing property. In this review, we therefore discuss biological and potential therapeutic effects of ortho-silicic acid and ortho-silicic acid -releasing silicon compounds as its major natural sources.
Highlights
Silicon (Si) is the most abundant element (27.2%) present in the earth's crust following oxygen (45.5%) [1]
Silicon is known for a number of important chemical and physical properties, i.e. semiconductor property that are used in various scientific and technical applications
Further condensation follows which is accompanied by dehydration yielding less hydrated silicon dioxide (SiO2) phases, known as “silica gel” or “amorphous silicon dioxide”
Summary
Silicon (Si) is the most abundant element (27.2%) present in the earth's crust following oxygen (45.5%) [1]. Dietary silicon in the form of sodium metasilicate activates formation of ammonia by elevating mitochondrial oxygen utilisation as shown in a controlled animal experiment [91] These findings further corroborate the hypothesis that sodium silicate might be responsible for immunostimulatory effects of BarodonW. In vitro and in vivo controlled animal studies have shown that clinoptilolite is an inert substance that may cause, in some instances, only moderate but not progressive fibrosis or mesothelioma [111] This effect might be attributed to side-substances present in natural zeolites, e.g. silica or clay aluminosilicates [112]. Animal studies have shown the possibility of zeolite A (sodium aluminosilicate) as a viable source of silicon [4,6,114] The latter is one of known zeolites that breaks down into bioavailable ortho-silicic acid (H4SiO4) in the digestive system. In a controlled study Turner et al [120] showed increased aluminium content in the bone and cartilage of zeolite A-fed calves which is an important safety issue for the zeolite A therapeutic usage
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
