all the compounds , except one i.e. , compound iv , showed analgesic activity which was much higher than met-enkephalin and morphine in mice and inhibited electrically induced contractions of isolated guineapig ileum , [ d-ala2 , met5 ] -enkephalin-morpholide and [ d-ala2 , met5 ] -enkephalin-beta-ala-amide were the most potent analgesics and nearly 6 and 500 times as active as morphine and met-enkephalin respectively .
C0014298
enkephalin
C0014295
met-enkephalin