(S (S (BASENP (DT The) (NN drug)) (VP (VBZ is) (VP (VBN known) (PP (IN as) (NP (BASENP (DT a) (NN maturation) (NN inhibitor)) (COMMA ,) (SBAR (WHNP (WDT which)) (S (VP (VBZ is) (NP (BASENP (DT a) (JJ new) (NN group)) (PP (IN of) (BASENP (NNS drugs)))))))))))) (PERIOD .))