Three esters of rhodamine B (1–3) differing in their alkyl chain lengths as well as several rhodamine B amides (4–9) were synthesized in good yields and tested for their cytotoxicity in SRB assays employing several human tumor cell lines. The rhodamine B esters were unselective but showed cytotoxicity of as low as EC₅₀ = 0.15 ± 0.02 µM. The rhodamine B amides were slightly less cytotoxic but showed good selectivity against MCF-7 and A2780 tumor cell lines. Especially a morpholinyl derivative 4 was ~20 time more cytotoxic for MCF-7 than for nonmalignant NIH 3T3 cells.

中文翻译：

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罗丹明B的酯和酰胺衍生物对不同的人类肿瘤细胞系产生细胞毒性作用

若丹明B（三个酯1 - 3在它们的烷基链长度以及若干若丹明B色酰胺（不同）4 - 9）以良好的收率合成和它们在使用几种人肿瘤细胞系SRB测定的细胞毒性测试。罗丹明B酯是非选择性的，但显示出低至EC ₅₀  = 0.15±0.02 µM的细胞毒性。罗丹明B酰胺的细胞毒性略低，但对MCF-7和A2780肿瘤细胞系表现出良好的选择性。特别是吗啉基衍生物4对MCF-7的细胞毒性比对非恶性NIH 3T3细胞高20倍。