Influence of solubility of ethanol extracts in artemia salina tests

Abstract

Tests with the microcrustacean Artemia salina are widely used by researchers of natural products as a quick and easy method applied to biological activity screening of natural products, including crude extracts. Median lethal concentration (LC50) values, obtained by means of the correlation among extract concentration and the quantity of A. salina dead, ≤ 1.000 μg mL-1, were considered as an indicative of biological activity. In this method, plant extracts should be dissolved in saltwater. However, the complete dissolution of samples to be tested is difficult to be reached. Thus, the solubility factor represents a strong interference parameter in determining the LC50 value, affecting the real biological potential evaluation of the nature product. In this context, when complete solubilization of extract is not observed, is herein suggested a methodological adaptation based on the use of DMSO or Tween 80, followed by filtration of the solution, before the in vitro assays. Additionally, the Probit model is recommended to obtain statistically significant values of LC50. Thus, the proposed methodological adaptation enhances the precision of the LC50 results.