Which extractant should be used for the screening and isolation of antimicrobial components from plants?

Freeze dried and finely ground leaves of two plants with known antimicrobial activity, Anthocleista grandiflora and Combretum erythrophyllum were extracted with acetone, ethanol, methanol, methylenedichloride, methanol/chloroform/water and water at a 1 to 10 ratio in each case. The quantity and diversity of compounds extracted, number of inhibitors extracted, rate of extraction, toxicity in a bioassay, ease of removal of solvent and biological...