# Online Database for Retrieval Information about Prebiotics and Their Activity
## 1 Introduction  
The human body is a complex system consisting of about \(10^{14}\) microbial cells interacting with the host [1; 2]. The essential role of the gut microbiota for health has generated tremendous interest in modulating its composition and metabolic function. One of these strategies is using prebiotics, which typically refers to selectively fermented non-digestible food ingredients or substances that specifically support the growth and/or activity of health-promoting bacteria (probiotics) that colonize the gastrointestinal tract [3; 4; 5]. As noted by [PERSON] et al. [6] prohibotics are <<live micro-organisms which when administered in adequate amounts confer a health benefit on the host. Prebiotics were defined as a non-digestible food ingredient that beneficially affects the host by selectively stimulating the growth and/or activity of one or a limited number of bacteria in the colon, and thus improves host health>> [7]. There are number of information systems and databases which have made it possible to collect various microbiological data, among which online databases should be highlighted [8; 9; 10; 11; 12]. The main purpose of Online Databases and Internet resources for science is to group data together and provide URLs and hyperlinks, such that any researcher, teacher, or student can accessthem with minimal effort, time, and cost [13; 14]. However, there are not a lot of databases or information systems in the fields of prebiotics and related to probiotics. A probiotics database named PROBIO was developed to facilitate these efforts and to address the need for information on the known probiotics, providing comprehensive information about the functions of marketed probiotics, clinical/field trials, and research probiotics for use or being studied for use in humans, animals, and plants [15]. This probiotic databases are typically focused on clinical research _in vitro_ or animal studies. The probiotic database PBDB [16] includes information about different probiotics sourced from fermented foods. Information about other Probiotics databases has been presented by the Probiotic Professionals site, where the most researched probiotic strains in the world are collected [17]. The strains have been chosen due to both the quantity and quality of the research behind them, but mainly by the quality. Some Web-sites of organizations specialize in the investigation of probiotics and prebiotics, such as that of the Global Prebiotic Association [18], where links on this theme have been collected. When considering prebiotics, it is necessary to pay great attention to their activity, which is an important task for estimating the perspectives of using such substances as prebiotics. There are different methods to evaluate prebiotic activity. The most commonly used technique for prebiotic activity evaluation _in vitro_ is based on the fermentation of mixed faecal cultures of healthy donors, which was first applied by Japanese researchers in the 1980s [19]. Simple batch fermentations are carried out and the pH is kept under control or not. Non-cultural methods of bacteria enumeration, such as fluorescence in situ hybridization (FISH) and polymerase chain reaction (PCR), have greatly enhanced the accuracy of prebiotic activity assessment. The range of analyzed prebiotics has been greatly expanded recently: exopolysaccharideacharide from _Cordycep s sinensis_ Cs-HK1 [20], xylooligosaccharides produced by _Bacillus subtilis_ 3610 [21], extracts of brown seaweed [22], and so on. Basing on the data obtained from the fermentation of fecal cultures, [PERSON], [PERSON], and [PERSON] [23] suggested calculation of a prebiotic index (PI), which was determined as the difference between the number of probiotics and non-probiotics at the end of the fermentation. [PERSON], [PERSON], and [PERSON] [24] replaced the number of bacteria by the specific growth rate, which demonstrated the relationship to the kinetic patterns of micro-organism growth; however, the mechanism of their interaction in a mixed culture remains hidden.