Water is a universal solvent. But all Phytochemicals may not be soluble in it. Thus use of other polar or non polar solvent is suggested to get most of the Phytochemicals screened. Methodology includes keeping the fresh crushed plant materials in water, or some other solvents of the choice over night on the shaker. Next day filtrate can be used for screening. Secondly, Soxhlet method can be used for extract preparation for Phytochemical screening.
Many aqueous extracts had some effect against microorganisms. But the primary aim of using water extracts is to reduce the economic cost of extraction. However, most of the research uses methyl alcohol to get the raw extract and then fragmented using a series of different solvents in the polar (chloroform, diethyl ether and water)