(S (S (NP (BASENP (JJ American) (NNS researchers)) (PP (IN at) (NP (NP (DT the) (NP (NP (BASENP (NNP University)) (PP (IN of) (BASENP (NNP Rochester)))) (BASENP (NNP Medical) (NNP Center)))) (PP (IN in) (BASENP (NNP New) (NNP York)))))) (VP (VBP say) (SBAR (IN that) (S (BASENP (PRP it)) (VP (MD could) (VP (VP (VB take) (BASENP (NNS months))) (S (VP (TO to) (VP (VP (VB develop) (BASENP (DT a) (JJ useable) (NN drug))) (PP (IN from) (NP (BASENP (DT the) (NN compound)) (COMMA ,) (BASENP (NN parthenolide))))))))))))) (PERIOD .))