Powis G, Ames M M, Kovach J S
Res Commun Chem Pathol Pharmacol. 1979 Jun;24(3):559-69.
Several pyrrolizidine alkaloids have been demonstrated to have antitumor activity in experimental tumor systems. In general the free base form of the alkaloid exhibits greater biological activity than the corresponding N-oxide and the N-oxide must be metabolized to the base for the subsequent formation of alkylating intermediates. Indicine N-oxide is an exception in that it is a more active antitumor agent than its free base indicine. Studies of the antitumor activity and metabolism of indicine N-oxide, and the closely related compound, heliotrine N-oxide, given orally and intraperitoneally to mice bearing P-388 leukemia, suggest that conversion of indicine N-oxide to indicine is not essential for its antitumor activity.
几种吡咯里西啶生物碱已被证明在实验性肿瘤系统中具有抗肿瘤活性。一般来说，生物碱的游离碱形式比相应的N-氧化物表现出更大的生物活性，并且N-氧化物必须代谢为碱才能随后形成烷基化中间体。印度娃儿藤碱N-氧化物是一个例外，因为它是比其游离碱印度娃儿藤碱更具活性的抗肿瘤剂。对印度娃儿藤碱N-氧化物以及密切相关的化合物天芥菜碱N-氧化物进行抗肿瘤活性和代谢研究，将其口服和腹腔注射给予携带P-388白血病的小鼠，结果表明印度娃儿藤碱N-氧化物转化为印度娃儿藤碱对其抗肿瘤活性并非必不可少。
