Isatin (2,3-Indolinedione) is an endogenous MAO inhibitor.

MAO-A:58 μM, MAO:15 μM, MAO-B:14 μM

Isatin诱导MCF-7细胞发生凋亡。Bcl-2表达降低，且Bcl-2与Bax的比率显著下降。Isatin处理后，线粒体跨膜电位显著降低，细胞色素c释放到胞质中的水平提高。同时，激活caspase-9和-3，随后导致一种caspase-3底物ICAD的降解。Isatin及其类似物抑制包括结肠HT29、乳腺MCF-7、肺A549和黑色素瘤UACC903细胞在内的某些癌细胞的增殖，是微管聚合和Akt路径的双重抑制剂[4]。

Isatin是一种内源性吲哚，其在压力下水平增加，能够抑制单胺氧化酶（MAO）B，且在大鼠的帕金森病模型中可改善运动迟缓并提高纹状体多巴胺水平。Isatin在大鼠脑及其他组织中具有独特而非连续的分布，脑中的最高浓度见于海马和小脑。在啮齿动物模型中，Isatin已被证实能引发一系列剂量依赖性的生理和生物作用，例如焦虑和镇定效应、记忆功能障碍以及抑制食物和水摄入。值得注意的是，Isatin可以轻易穿过血脑屏障，因此，100 mg/kg的腹腔剂量能在大鼠脑中产生约120 μM的浓度。这个浓度会随着重复注射而进一步增加[2]。

Cell viability was estimated by a colorimetric method, which is based on the ability of cellular dehydrogenases of viable cells to reduce MTT from a yellow watersoluble dye to a dark blue insoluble formazan product. SHSY5Y cells were seeded in 96-well plates at 4×104 cells/well/(100 ml) and allowed to attach. The cells were then treated with isatin and returned to the incubator for 24 or 48 h. MTT 25 μl (5 mg/ml) was added to all wells and allowed to incubate in the dark at 37℃ for 2 h followed by cell lysis. The plates were read with an OPTImax microplate reader at wavelength of 562 nm. Controls included untreated cells and medium alone, with all MTT assays performed in triplicate.(Only for Reference)