Pharmacology & Pharmacy, 2010, 1, 69-74 doi:10.4236/pp.2010.12010 Published Online October 2010 (http://www.SciRP.org/journal/pp) Copyright © 2010 SciRes. PP 69 The Study of Influence of Silica and Polyethilene Glycols Organic-Inorganic Compounds on Free-Radical Processes in Vitro Olga G. Sitnikova 1 , Sergey B. Nazarov 1 , Irina V. Shikhanova 2 , Alexander V. Agafonov 2 , Jean A. Dyuzhev 1 , Irina G. Popova 1 1 Ivanovo State Research Institute of Maternity and Childhood (RIMC), Ivanovo, Russia; 2 Institute of Solution Chemistry, Russian Academy of Sciences, Ivanovo, Russia. Email: ivgenlab@gmail.com Received July 20 th , 2010; revised August 10 th , 2010; accepted September 30 th , 2010. ABSTRACT In this study investigation of influence of hybrid nanosilica-polyethylene glycols materials (molecular weight 1500, 6000 and 15000), prepared by sol-gel synthesis, on lipid peroxidation and antioxidant activity of human serum in vitro was performed. Methods included chemiluminescence analysis and quantitative malonic dialdehyde estimation. It was revealed that nanosilica-PEG materials with different molecular weight had certain biological activity. Powders of SiO 2 -PEG 1500 and SiO 2 -PEG 6000 manifest prooxidant effects, whereas mesoporous (calcine) powders produced antioxidant effects in blood serum in vitro. Keywords: Free-Radical Oxidation, Nanosilica, Chemiluminescence, Malonic Dialdehyde 1. Introduction The study of free-radical processes of lipid oxidation and antioxidant system is an important problem of modern biomedicine. Oxygen is a powerful oxidant and oxy- gen-mediated reactions are the main sources of energy for variety of biological species. Metabolic processes produce reactive oxygen species (ROSs), free radicals, peroxides, malonic dialdehyde, Schiff's bases, which damage membrane structures and lead to oxidative stress, being the causative factor for a lot of widely spread dis- eases, including reproductive disorders and prenatal inju- ries [1-3]. Concerning this the role of antioxidants is to neutralize toxic products of free-radical lipid peroxidation. In con- ditions of excessive peroxidation the capacity of antioxi- dant defense may decrease due to insufficient endogenic antioxidant production or unfavorable environment fac- tors [3]. Various substances are known to have antioxi- dant activity; their investigation is of certain importance for both biology and medicine [4]. Nowadays silica compounds attract considerable at- tention. Silica stimulates fibroblastic activity of mesen- chyma, promoting granulation and scarring. The lack of silica may lead to depression of leukocyte activity in in- flammation, poor wound scarring, anorexia, pruritus, tissue flexibility decrease, skin turgor decrease, vascular permeability increase and haemorrhagia as a result. Apart from this silica antioxidant activity stands [5]. Investigators of peroxidation showed that silica pow- ders stimulated active oxygen species and free radicals production in culture of epithelial cells, resulting in cas- pase activation and apoptosis [6]. Some authors experi- mentally found out that inhalation of crystalloid silica in animals lead to oxidative stress, inflammation and alveo- lar fibrosis [7,8]. As a catalysts and functional composite materials spe- cial attention is attracted by matrix hybrid silica derivates. In this study we presented physical-chemical properties of silica-based materials and their influence on peroxida- tion processes in human serum. Silica nanoparticles are biologically inert, have high adsorption rate, thermal and mechanic stability, and therefore are expected to mani- fest antioxidant activity. The aim of the work was to study the influence of or- ganic-innorganic silica and polyethylene glycols com- pounds on free-radical processes in vitro.