Recently, our group isolated and reported the antiproliferative activity in promastigotes and axenic amastigote forms of Leishmania amazonensis treated with 5-methyl-2,2':5',2″-terthiophene (compound A) and 5'-methyl-[5-(4-acetoxy-1-butynyl)]-2,2'-bi-thiophene (compound B) isolated from the aerial