To investigate the metabolism of cryptolepine and some cryptolepine analogues by aldehyde oxidase, and to assess the implications of the results on the potential of cryptolepine analogues as antimalarial agents.
The products resulting from the oxidation of cryptolepine and 2-fluorocryptolepine by a rabbit liver preparation of aldehyde oxidase were isolated and identified using chromatographic and spectroscopic techniques. The antiplasmodial activity of cryptolepine-11-one was assessed against Plasmodium falciparum using the parasite lactate dehydrogenase assay.
Cryptolepine was oxidized by aldehyde oxidase give cryptolepine-11-one. Although 2-fluorocryptolepine was found to have less affinity for the enzyme than cryptolepine, it was a better substrate for aldehyde oxidase than the parent compound. In contrast, quindoline, the 11-chloro- , 2,7-dibromo- and 2-methoxy analogues of cryptolepine were not readily oxidized. Cryptolepine-11-one was found to be inactive against P. falciparum in vitro raising the possibility that the effectiveness of cryptolepine as an antimalarial, may be compromised by metabolism to an inactive metabolite by liver aldehyde oxidase.
Cryptolepine and 2-fluorocryptolepine are substrates for aldehyde oxidase. This may have implications for the design and development of cryptolepine analogues as antimalarial agents.
研究aldehyde oxidase对cryptolepine和一些cryptolepine类似物的代谢,并评估结果对cryptolepine类似物作为抗疟疾药物潜力的影响。
使用兔肝制备的aldehyde oxidase氧化cryptolepine和2-氟cryptolepine,分离和鉴定产物,使用色谱和光谱技术。使用寄生物乳酸脱氢酶测定法评估cryptolepine-11-one对恶性疟原虫的抗疟活性。
aldehyde oxidase氧化cryptolepine形成cryptolepine-11-one。虽然2-氟cryptolepine与cryptolepine相比对酶的亲和力较低,但它是比母体化合物更好的aldehyde oxidase底物。相反,11-氯、2,7-二溴和2-甲氧基类似物quindoline不容易被氧化。在体外,发现cryptolepine-11-one对P. falciparum无活性,这可能意味着cryptolepine作为抗疟药物的有效性可能会受到肝脏aldehyde oxidase代谢为无活性代谢物的影响。
cryptolepine和2-氟cryptolepine是aldehyde oxidase的底物。这可能对cryptolepine类似物作为抗疟疾药物的设计和开发产生影响。