Please treat as urgent

Dear Colleagues , please I want to know the basis for using 10%, 20% and 30% LD50 as dose concentrations?

Secondly, is it correct to compare the biochemical assays of two fruit extracts(ripe and unripe) whose doses are unequal(ripe-360, 720, 1080mg/kg) and (unripe-500, 1000, 1500mg/kg). please note that the doses were calculated based on 10%LD50?

Please references should be stated?